TABLE OF CONTENTS. SECTION 1 INTRODUCTION 1.1 Background Purpose and Scope

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2 TABLE OF CONTENTS EXECUTIVE SUMMARY... Page ES-1 SECTION 1 INTRODUCTION 1.1 Background Purpose and Scope SECTION 2 BASIS OF DESIGN 2.1 Existing Discharge Permit Plant Capacity Evaluation per TCEQ Requirements Data Gathering and Analysis Design Criteria Design Flows Loadings SECTION 3 PRELIMINARY DESIGN 3.1 Intake Structure Alternatives Cost Analysis Grit Removal Alternatives Cost Analysis Aeration Basins Rehabilitation Required Air Flow Basin No Basins Nos. 2 and Basins Nos. 4 and Aeration System Replacement Recommendations Blower Alternatives Blower Cost Analysis Air Piping Filtration System UV System Actuated Slide Gates Electrical Equipment Intake Structure Actuated Slide Gates Blowers UV System Recommended Improvements Klotz Associates Project No March 2012 TOC-1 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

3 SECTION 4 COST ESTIMATES 4.1 Construction Cost SECTION 5 PHASED APPROACH TO IMPLEMENTING BLACKHAWK WWTP REHABILITATION 5.1 Construction Packages 1 and Construction Packages 3 and Klotz Associates Project No March 2012 TOC-2 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

4 LIST OF FIGURES Figure 1-1 Figure 3-1 Figure 3-2 Figure 3-3 Figure 3-4 Figure 3-5 Figure 3-6 Figure 3-7 Figure 3-8 Existing Process Flow Diagram Site Layout Existing Influent Structure Modifications Plan Hydraulic Profile Aeration Basin No.1 Fine Bubble Diffusers Plan and Section Aeration Basins No. 2 & 3 Fine Bubble Diffusers Plan Aeration Basins 4 & 5 Fine Bubble Diffusers Plan UV Disinfection System Plan Proposed Process Flow Diagram Klotz Associates Project No March 2012 TOC-3 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

5 LIST OF TABLES Table 2-1 Plant Capacity Evaluation per TCEQ Requirements Table 2-2 Flow Data Summary January July 2011 Table 2-3 Plant Raw Influent Grab Sampling Data Table 2-4 Plant Raw Influent 24 hours Composite Sampling Data Table 3-1 Intake Structure Construction Cost Comparison Table 3-2 Annual Energy Costs for Grit Removal Operation for Alternative 1 Table 3-3 Net Present Worth Analysis of Grit Removal Alternatives Table 3-4 Present Net Value Comparison of Fine Bubble vs Coarse Bubble in Aeration Basin 1 Table 3-5 Present Net Value Comparison of Fine Bubble vs Existing Surface Aeration in in Aeration Basins 2 and 3 Table 3-6 Present Net Value Comparison of Fine Bubble vs Coarse Bubble in Aeration Basins 4 and 5 Table 3-7 Annual Energy Costs for Blower Operation for Alternatives 1, 2, and 3 Table 3-8 Net Present Worth Analysis of Blowers Replacement Table 3-9 Filter Rehabilitation vs Filter Retrofit with AquaDiamond System (Aqua- Aerobics Systems, Inc.) Table 4-1 Engineer s Opinion of Probable Cost Original Scope Table 4-2 Engineer s Opinion of Probable Cost Including Alternatives Table 4-3 Engineer s Opinion of Probable Cost Packages 1 and 2 Table 4-4 Engineer s Opinion of Probable Cost Packages 3-1, 3-2 and 3-3 Table 4-5 Engineer s Opinion of Probable Cost Package 4 Klotz Associates Project No March 2012 TOC-4 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

6 APPENDICES Appendix A Appendix B Appendix C Appendix D Appendix E Appendix F Appendix G Appendix H TPDES Permit Influent Structure Structural Evaluation Report Grit Removal System References Required Air Flow Calculations Existing Aeration Blowers System Curves Air Headloss Calculations Jestec Field Services, Inc. Field Report Delta Structural Technology Proposal Klotz Associates Project No March 2012 TOC-5 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

7 EXECUTIVE SUMMARY Background The Blackhawk Wastewater Treatment Plant (WWTP) is owned and operated by the Gulf Coast Waste Disposal Authority (GCA). The Blackhawk WWTP treats wastewater from the City of Friendswood, Municipal Utility District 55, Baybrook MUD I, and part of the City of Houston. The existing Plant utilizes conventional wastewater treatment technology consisting of complete mix aeration tanks followed by secondary clarifiers, traveling bridge tertiary filters, and UV disinfection. Process solids treatment consists of gravity thickening followed by aerobic digestion and dewatering of solids by a belt filter press. The existing process flow diagram is shown on Figure 1-1. The Site layout is shown on Figure 3-1. The Plant operates under the TPDES permit No.WQ issued on November 25, 2008 with the expiration date of September 1, 2013 (see Appendix A). In May 2010 Klotz Associates completed a Rehabilitation Study including evaluation and construction cost estimate of the recommended plant improvements. In September 2011 Klotz Associates completed first draft of this Preliminary Engineering Report (PER). In November 2011 Klotz Associates had the PER review meeting with the GCA administrative, engineering, and operations personnel. GCA requested Klotz Associates to evaluate additional rehabilitation alternatives. This PER summarizes the 2010 findings and evaluates additional design alternatives for rehabilitation and replacement at the request of GCA. Klotz Associates Project No March 2012 ES-1 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

8 Statement of the Problem In general, most of the Blackhawk WWTP equipment has reached the end of their intended design life. While some equipment has been replaced or rebuilt over the years, the majority of the plant equipment and structures were installed during 1977 original construction and the 1984 upgrade. Because of its age, condition, and energy usage some of the process equipment and structures should be given top priority for replacement and/or rehabilitation. Project Base Solution As part of the 2010 Klotz Associates rehabilitation study the following improvements were recommended: Install two mechanical bar screens with associated washer/compactor, conveyor and controls as shown on Figure 3-2. Replace the existing medium bubble diffusers with fine bubble diffusers including associated piping and controls in aeration basins Nos. 1, 4 and 5 as shown on Figures Nos. 3-4 and 3-5. Remove the existing surface aerators and install a fine bubble diffuser aeration system with associated air piping, control valves, and fitting in aeration basins Nos. 2 and 3 as shown on Figure No Rehabilitate the 1977 Infilco Degremont ABW traveling bridge filters. Replace the 1993 Trojan UV disinfection system as shown on Figure 3-7. Replace the existing multistage 75 HP blowers installed in 1984 with new multistage centrifugal blower similar to the existing blowers 1, 2, and 3. Replacement and/or modifications of electrical, control, and SCADA equipment associated with rehabilitation/replacement work described above. Klotz Associates Project No March 2012 ES-2 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

9 Additional items for possible replacement/rehabilitation were identified during a July 2011 meeting with the GCA administrative and operations personnel: Evaluate feasibility of installation of a grit chamber between the proposed mechanical screens and the existing aeration basins to mitigate possible maintenance issues associated with clogging of proposed fine bubble diffusers. Perform a structural analysis with recommendation for repair or replacement of the existing intake structure. Install electrical actuators on the existing isolation slide gates at the clarifiers splitter structure, and UV channel. Based on life cycle cost analysis, evaluate the replacement of the three existing multistage centrifugal blowers with new variable speed single stage turbo blowers with associated automatic controls and instrumentation. Also, the following additional items were identified and evaluated by Klotz Associates for possible inclusion in the final design of the project: Install dissolved oxygen (DO) meters in the existing aeration tanks for more efficient process control and operation especially in conjunction with proposed variable speed blowers. Install air flow meters at the blowers discharge manifold piping for monitoring and control of air flow distribution between the aeration tanks. Replace the existing isolation slide gates at the intake structure with rectangular or trapezoidal weir gates. Weir gates will be custom fabricated with different weir crest length to allow tank volume proportional influent flow distribution between the aeration tanks. Install flow sensor/transmitter at the intake structure for monitoring of influent flow to the aeration tanks. Klotz Associates Project No March 2012 ES-3 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

10 The proposed modifications are shown on Figure 3-8. Locations of proposed modifications are shown Figure 3-1. The following additional items were identified for evaluation during a November 2011 meeting with GCA personnel: Perform additional structural evaluation of the existing structure, and provide a detailed itemized rehabilitation cost evaluation and determine the expected service life of the structure. Also, provide a life cycle cost analysis of the existing structural rehabilitation versus building a new intake structure. Prepare a revised cost estimate for rehabilitation of the traveling bridge filter in lieu of replacement. Also, perform an analysis of available methodologies for procurement and construction of new equipment as a stand-alone project. Prepare an analysis of available methodologies for procurement and construction of new equipment as a stand-alone project. A cost estimate for the rehabilitation of the UV system will be prepared. Provide a life cycle cost analysis of each of the aerations basins individually as standalone projects: basin 1 rehabilitation, basins Nos. 2 and 3 rehabilitation, and basins Nos. 4 and 5 rehabilitation All rehabilitation options will include life cycle analysis including annual maintenance costs for diffusers, annual grit removal and an estimated service life of 20 years. Evaluate an additional alternative for aeration blower rehabilitation: keep the existing air piping layout of all blowers discharging into a common manifold with control valves for flow distribution to individual basins. Flow to each individual basin will be controlled by the motorized automatically controlled valve. Klotz Associates Project No March 2012 ES-4 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

11 Evaluation of Alternative Solutions Intake Structure Alternatives Two potential alternatives were developed for the intake structure as follows: Alternative 1: This alternative includes replacement of the existing intake structure with a new intake structure. The new intake structure will include a flow splitter box equipped with flow proportional weir gates and new mechanical bar screens with associated washer/compactor, conveyor and controls. This new intake structure will be constructed to the north of the existing structure as shown on Figure 3-1. Additional work includes new piping and fittings for tie-in to the existing force mains and flow distribution between aeration tanks. Alternative 2: This alternative includes rehabilitation of the existing intake structure to accommodate proposed mechanical bar screens with associated washer/compactor, conveyor and controls. Rehabilitation will include cleaning the walls and chipping away loose concrete down to a solid concrete core. Any remaining reinforcing steel will need to be cleaned and have any rust removed. A new layer of steel reinforcing bars would have to be drilled or groove cut epoxied into the wall to replace damaged and missing bars, and the concrete would have to be replaced with expansive high strength epoxy cement that could fill all of the voids created by the damaged concrete. The repaired structure would then have to be relined with a new corrosion resistant liner that would prevent further damage (refer to Appendix B of the PER for Influent Structure evaluation report). The existing slide gates at the intake structure flow splitter box would be replaced with flow proportional weir gates. Flow sensors/transmitter would be installed for monitoring and control of influent flow distribution between aeration tanks. Incidental work will include Klotz Associates Project No March 2012 ES-5 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

12 installation of temporary by-pass piping for diversion of the external and internal pump stations flows. Cost evaluation of intake structure alternatives is presented in Table 3-1. Grit Removal Alternatives Two alternatives were developed for grit removal at the Blackhawk WWTP. Alternative 1: This alternative includes construction of a new grit chamber between the mechanical bar screens and aeration tanks. Considering head loss through the proposed grit chamber and discharge weir, this alternative cannot be used with the existing intake structure because of insufficient hydraulic head to overcome additional grit chamber head losses at the two-hour peak flow of MGD as shown on Figure 3-3. Annual energy costs for a new grit chamber are summarized in Table 3-2. Alternative 2: Perform regular drainage and grit removal from the aeration tanks in lieu of a grit removal system. Summary of cost analysis of grit removal alternatives is presented in Table 3-3. Aeration system rehabilitation alternatives: This additional aeration system evaluation was done in response to the November 2011 meeting with the GCA personnel. Each basin or pair of basins was evaluated individually. Basin No. 1 Alternative 1: Replacement of the existing medium bubble diffusers with fine bubble diffusers. Alternative 2: Replacement of the existing medium bubble diffusers with combination of new coarse bubble diffusers and a submersible mixer. Klotz Associates Project No March 2012 ES-6 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

13 Basins No. 2 and 3 Alternative 1: Replacement of the existing surface aerators and medium bubble diffusers with fine bubble diffusers. Alternative 2: No change to existing surface aerators and medium bubble diffusers. Basins No. 4 and 5 Alternative 1: Replacement of the existing medium bubble diffusers with fine bubble diffusers. Alternative 2: Replacement of the existing medium bubble diffusers with new coarse bubble diffusers. Aeration Blowers Alternatives Three potential alternatives for aeration blowers were developed. Alternative 1: This alternative includes replacement of three existing multistage 250 HP blowers and two 75 HP blowers with new variable speed single stage turbo blowers with associated automatic controls and instrumentation. There will be four new blowers based on the TCEQ blower redundancy criterion. Each aeration tank will have a dedicated blower and air header. Blower speed will be controlled based on measured dissolved oxygen concentration in each tank transmitted from DO sensor/transmitter. The blowers discharge piping will be designed to allow use of the standby blower with any of the aeration tanks. Alternative 2: This alternative is based on the fact that three existing 250 HP multistage blowers have sufficient aeration capacity for all three aeration tanks based on the permitted flow without redundancy. The 75 HP multistage centrifugal blowers installed in 1984 do not have sufficient capacity for either one of the five aeration basins, and at least one of the blowers has to be replaced with the new blower to meet TCEQ redundancy criterion. The Klotz Associates Project No March 2012 ES-7 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

14 250 HP blowers were rebuilt in Additional equipment in Alternative 2 includes an automatically controlled blower intake valve for each blower (new and existing) with associated control panel and instrumentation. Each aeration tank will have a dedicated blower and air header similar to Alternative 1. Blower intake valve position will be controlled based on measured dissolved oxygen concentration in each tank transmitted from DO sensor/transmitter. The blowers discharge piping will be designed to allow use of the standby blower with any of the aeration tanks. Alternative 3: This alternative is similar to alternative 2 but with a different air piping layout: three existing blowers and one new multistage blower are connected to a common manifold with motor-operated valves (MOV) to direct the required air flow to each basin based on the pre-set pressure as measured by a pressure transducer. Annual energy cost for each alternative is summarized in Table 3-7. In addition, a cost analysis of the blower alternatives is presented in Table 3-8. Recommended Project Intake Structure Alternatives Klotz Associates recommends Alternative 1: construction of a new intake structure. The construction cost of the new intake structure is approximately 5 % ($48,000) higher than rehabilitation of the existing structure as presented in Table 3-1. The service life of a new structure is expected to be approximately 50 years but the projected lifespan of the rehabilitated structure is uncertain. Retrofitting the existing Intake Structure with new mechanical screens and appurtenances would require modifications for necessary access to the equipment for operations and maintenance. In addition, the new structure will accommodate addition of the grit removal system in the future. The elevation of the existing Klotz Associates Project No March 2012 ES-8 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

15 intake structure does not have sufficient hydraulic head for grit chamber installation based on the 2-hour peak flow. Grit Removal Alternatives Klotz Associates recommends Alternative 2: manual grit removal. The recommendation is based on the Present Net Value (PNV) life cycle cost analysis of two alternatives as presented in Table 3-3. A grit removal system costs more than manual grit removal from the aeration basins, however the grit removal system has the advantage of reducing wear on plant equipment such as the return activated sludge pumps and the waste activated sludge pumps. Grit removal system can be installed at a later date as a stand-alone construction project. The new intake structure will be designed to allow future addition of the grit removal system without any structural modifications of the intake structure. Aeration Blowers Alternatives Klotz Associates recommends Alternative 1: replacement of three existing 250 HP blowers and one 75 HP blowers with four variable speed turbo blowers. The recommendation is based on the PNV life cycle cost analysis of two alternatives as presented in Table 3-8. The alternative has a simple payback of approximately 8 years. Estimated Construction Costs Klotz Associates prepared the preliminary construction cost estimates for items identified during the 2010 Klotz Associates rehabilitation study as well as additional items identified during the July 2011 meeting with the GCA personnel. Several items were included in the cost estimates that are not in scope, but were deemed important enough to include in the project such as installation of DO meters in aeration tanks, weir gates in the intake structure, and air flow meters on the blower discharge piping. All cost estimates include 20% contingency. The construction cost estimate of the project is as follows: Klotz Associates Project No March 2012 ES-9 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

16 Description Estimated Cost of Construction Original Scope of Work $4,796,000 Scope of Work including recommended Alternatives $6,447,000 Detailed cost estimates are included in Tables 4-1 and 4-2 of the PER. The recommended alternative cost estimate includes new intake structure (excluding grit chamber) and replacement of all existing multistage centrifugal blowers with single stage variable speed blowers. The project can be split into the following construction packages: Top Priority Items Package No. 1: Intake structure replacement with a total construction cost of $1,098,000. Package No. 2 is UV system replacement and travelling bridge rehabilitation with a total construction cost of $2,160,000. See Table 4-3 for a cost estimate summary. Note that Package 1-B to Rehabilitate Existing Intake Structure is approximately the same cost as building a new intake structure. Second Priority Items Package No. 3: Aeration tanks aeration system replacement stand-alone projects (Table 4-4) are as follows: Package No. 3-1 Aeration Basin No. 1 construction cost: $585,000 Package No. 3-2 Aeration Basins Nos. 2 and 3 construction cost: $817,000 Package No. 3-3 Aeration Basins Nos. 4 and 5: $389,000 Total construction cost for Package 3: $1,7891,000. Package No. 4 Blowers replacement including new control system and instrumentation with a total construction cost of $1,446,000. See Table 4-5 for a cost estimate summary. Packages Nos. 3 and 4 can be combined into a single package with a total cost of $3,237,000. Klotz Associates Project No March 2012 ES-10 Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

17 SECTION 1 INTRODUCTION 1.1 Background The original Blackhawk Wastewater Treatment Plant (WWTP) was constructed in The original facilities consisted of head works (decommissioned during 1984 upgrade), circular clarification unit (currently aeration tank No.1), two aeration basins with surface aerators (currently aeration tanks Nos. 2 and 3), final clarifiers (currently aerobic digester), gravity filters, chlorine contact basin (subsequently retrofitted into UV disinfection system), outfall structure, and gravity sludge thickener with associated thickened sludge pumps. In 1984 the plant was upgraded with the construction of two additional aeration tanks (aeration basins Nos. 4 and 5) equipped with medium bubble diffused aeration system and associated multistage centrifugal blowers. In addition, the original circular clarification treatment unit was retrofitted into an aeration tank with coarse bubble diffused aeration system (aeration tank No. 1). Other upgrades included the addition of two circular secondary clarifiers with associated Return Activated Sludge Pumps (RAS) and a new solids treatment facility. The new solids treatment facility consisted of a four section aerobic digester (retrofitted secondary clarifiers) with associated blowers and aeration system, digested sludge pumps, and a solids process building housing two Belt Filter Presses (BFP). In 1993 the most recent upgrade project was completed. The 1993 project included construction of three additional Aqua Aerobics traveling bridge filters, retrofit of the previously constructed chlorine contact chamber into dual channel UV disinfection system equipped with Trojan UV 3000 Classic System, and construction of the hydro-pneumatic tank. All the existing structures and equipment, excluding the 1977 Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

18 head works structure, are still in operation. The Existing Process Flow Diagram is shown on Figure 1-1. In general, most of the Blackhawk WWTP equipment has reached the end of its intended design life. While some equipment has been replaced or rebuilt over the years, the majority of the plant equipment and structures is original from the 1977 and 1984 construction. Because of its age, condition, and energy usage some of the process equipment and structures should be given top priority for replacement and/or rehabilitation. Rehabilitation or replacement of the intake structure, aeration system, filters and ultraviolet (UV) disinfection system are the high priority unit processes. The comminutor in the influent channel is not functioning. The intake structure receives turbulent flows that lead to gas stripping and has deteriorated the concrete. Another priority renovation is to replace the aging and inefficient mechanical and bubble aerators in the aeration basins. The automatic backwash traveling bridge sand filters have outlived their intended life and require rehabilitation (see Appendix G). The UV disinfection system needs expansion and renovation; currently it operates at full capacity with no redundancy. GCA requested that as part of the PER, the alternatives reviewed should, where possible, incorporate innovative approaches that may offer cost reducing solutions, especially electrical savings. 1.2 Purpose and Scope This PER describes the evaluation and recommendations for replacement and/or rehabilitation of specific items of process equipment at the Blackhawk WWTP. The purpose of the PER is to: Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

19 Identify viable rehabilitation or replacement alternatives by performing a review of the current plant drawings, conducting site visits, interviewing GCA personnel and reviewing equipment options with various equipment vendors. Identify viable energy and cost savings alternatives. Develop preliminary designs for the project. Develop preliminary construction cost estimates. As part of the 2010 Klotz Associates rehabilitation study, the following improvements were identified: Install two mechanical bar screens with associated washer/compactor, conveyor and controls as shown on Figure 3-2. Replace the existing medium bubble diffusers with fine bubble diffusers including associated piping and controls in aeration basins Nos. 1, 4 and 5 as shown on Figure Nos. 3-4 and 3-5. Remove the existing surface aerators and install a fine bubble aeration system with associated air piping, control valves, and fittings in aeration basins Nos. 2 and 3 as shown on Figure No Rehabilitate the 1977 Infilco Degremont ABW traveling bridge filters. Replace the 1993 Trojan UV disinfection system as shown on Figure 3-7. Replace the existing multistage 75 HP blowers installed in 1984 with a new multistage centrifugal blower similar to the existing blowers 1, 2, and 3. Replacement and/or modifications of electrical, control, and SCADA equipment associated with rehabilitation/replacement work described above. Additional items for possible replacement/rehabilitation were identified during a July 2011 meeting with the GCA personnel: Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

20 Evaluate feasibility of installation of a grit chamber between the proposed mechanical screens and the existing aeration basins to mitigate possible maintenance issues associated with clogging of proposed fine bubble diffusers. Perform structural analysis and provide a recommendation for repair or replacement of the existing intake structure. Install electrical actuators on the existing isolation slide gates at the clarifiers splitter structure, and UV channel. Based on life cycle cost analysis, evaluate the replacement of the three existing multistage centrifugal blowers with new variable speed single stage turbo blowers and associated automatic controls and instrumentation. Also, the following additional items were identified and evaluated by Klotz Associates for possible inclusion in the final design of the project: Install DO meters in the existing aeration tanks for more efficient process control and operation especially in conjunction with proposed variable speed blowers. Install air flow meters at the blowers discharge manifold piping for monitoring and control of air flow distribution between the aeration tanks. Replace the existing isolation slide gate at the intake structure with adjustable weir gates. Weir gates will allow tank volume proportional flow distribution between the aeration tanks. Install flow sensors/transmitters at the intake structure weir gates for monitoring and control of influent flow to the aeration tanks. The following additional items were identified for evaluation during a November 2011 meeting with GCA personnel: Perform additional structural evaluation of the existing structure, provide an itemized rehabilitation cost evaluation and determine the expected service life of Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

21 the structure. Also, provide a life cycle cost analysis of the existing structural rehabilitation versus building a new intake structure. Prepare a revised cost estimate for rehabilitation of the traveling bridge filter in lieu of replacement. Also, an analysis of available methodologies for procurement and construction of new equipment as a stand-alone project will be performed. Prepare an analysis of available methodologies for procurement and construction of new equipment as a stand-alone project. A cost estimate for the rehabilitation of the UV system will be prepared. Provide a life cycle cost analysis of each of the basins individually as stand-alone projects. All options including fine bubble aeration will include annual maintenance costs for the diffusers, annual grit removal and an estimated service life of 20 years. A description of the evaluation of items from the November 2011 meeting and its conclusions can be found in Section 4. Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

22 SECTION 2 BASIS OF DESIGN 2.1 Existing Discharge Permit The current discharge permit for the Blackhawk WWTP plant is permit number WQ It became effective November 28, 2009 and expires September 1, The permit allows discharge into Clear Creek Tidal in Segment No of the San Jacinto-Brazos Coastal Basin. The annual average flow of effluent shall not exceed 9.25 million gallons per day (MGD); nor shall the average discharge during any two-hour period (2-hour peak) exceed 19,270 gallons per minute (GPM), or 27.6 MGD. Permitted effluent discharge limits for Average Daily Flow are as follows: CBOD 5 daily average TSS daily average Ammonia Nitrogen daily average Enterococci Bacteria daily average 5 mg/l 12 mg/l 2 mg/l 35 colonies per 100 ml A copy of the permit is included in Appendix A. 2.2 Plant Capacity Evaluation per TCEQ Requirements The Blackhawk WWTP was evaluated for compliance with current TCEQ design requirements for Wastewater Treatment Facilities (Chapter 217). The summary of the evaluation is presented in Table 2-1. Because the existing aeration tanks have different volumes, their required capacity was evaluated individually. Based on the permitted average annual flow of 9.25 MGD and BOD 5 of 281 mg/l the existing Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

23 aeration tanks have 89 % of their required capacity per TCEQ design requirements. However, considering that actual Annual Average Flow (AAF) to the Plant is approximately 60% of its permitted AAF, the Blackhawk WWTP has sufficient aeration capacity. As shown in Table 2-1, the secondary clarifiers have some additional capacity. 2.3 Data Gathering and Analysis GCA provided Adobe PDFs of plant drawings, a copy of the TCEQ discharge permit, plant flow, Ammonia-Nitrogen, TSS and BOD 5 sampling data, power bills and equipment information. Klotz Associates contacted equipment vendors and obtained drawings, cut sheets, information and cost data for new equipment proposed for the site. 2.4 Design Criteria Design Flows A summary of flows for is presented in Table 2-2. Flows for the Blackhawk WWTP are summarized below: Annual Average Daily Flow (AAF) 5.53 MGD Maximum Monthly Average Flow (MMAF) 6.75 MGD Maximum Daily Flow (MDF) MGD Peak Flow (PF) 19,167 GPM MDF/AAF 2.96 PF/AAF 5.0 MMAF/ADF 1.22 Permit ADF 9.25 MGD Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

24 Permit 2-Hour Peak 19,270 GPM Loadings The Plant Raw Influent Grab Sampling Data for ammonia, BOD 5, and Total Suspended Solids (TSS) are presented in Table 2-3. Grab samples are collected from the intake structure that also receives in-plant return flows as shown on Figure 1-1. The in-plant return flow may cause occasional spikes in influent parameters, especially BOD 5. To verify consistency of the data the plant personnel collected and analyzed 24 hour composite sampling data of the raw samples as presented in Table 2-4. Comparison of the 2.5 years of the annual average of grab sampling data with the 24 hours composite sampling data revealed close correlation of the data. The higher BOD 5 and ammonia data were used in preliminary design calculations. The design BOD 5 loading is 286 mg/l. This value is the average daily BOD 5 from plant records during the period January 2009 through June 2010 plus one standard deviation. The addition of one standard deviation is consistent with TCEQ standard design criteria. The design ammonia-nitrogen loading is 30.5 mg/l. This value is the average of daily ammonia-nitrogen readings recorded from January through December The addition of one standard deviation is consistent with TCEQ standard design criteria. Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

25 SECTION 3 PRELIMINARY DESIGN 3.1 Intake Structure Alternatives Paul Engineering, Inc., under subcontract to Klotz Associates, completed a structural evaluation of the Blackhawk WWTP influent intake structure. Based on a site inspection on August 4, 2011 and structural analysis, Paul Engineering determined that extensive corrosion to the vertical reinforcing steel at the water line compromises the structure s structural integrity. Specifically, the structure is not able to resist the required lateral loads if one chamber is filled with water and the adjacent chamber is empty. Paul Engineering recommends (1) that the structure be replaced or (2) that the intake structure s walls be rehabilitated to ensure structural integrity (refer to Appendix B for Influent Structure evaluation report). Paul Engineering conducted an additional evaluation of the existing intake structure on December 21, 2012 in order to provide an itemized rehabilitation cost evaluation (see Appendix H). Alternative 1 includes replacement of the existing intake structure with a new structure including new flow proportional weir gates, and new mechanical bar screens with associated washer/compactor, conveyor and controls. The new structure will be constructed to the north of the existing intake structure alternative as shown on Figure 3-1. The existing force mains and process piping will be re-routed to the proposed intake structure. Required modifications to the existing intake structure per Alternative 2 would include the following: Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

26 Clean existing structure to remove all sewage and existing coatings and liners down to clean concrete. Remove loose material by chipping the old loose damaged concrete out until a solid concrete core is found; Clean exposed reinforcing steel, removing any rust; Install a new layer of steel reinforcing bars where required, either by drilling into existing concrete or groove cut epoxy the new bars into the wall to replace missing or damaged bars, place fiberglass patch over all repaired concrete areas to seal and tie all damaged concrete to existing concrete. Replace concrete with expansive high strength epoxy cement that could fill all the voids created by the damaged concrete; Reline structure with a corrosion-resistant coating to prevent further corrosion. Construct additional platform adjacent to the structure as shown on Figure 3-2 to house bar screens and compactor control panels The intake structure will be bypassed during work inside of the structure since repairs cannot be done on any walls with wastewater in place in an adjacent chamber. Related work to Alternative 2 would include installation of temporary by-pass piping for diversion of the external and internal pump stations flows. The diversion would require that the influent pipes be diverted directly into the aeration basins. The 24- inch force main can be diverted at the old headworks structure and directed to one of the aeration basins. Refer to Appendix H for detailed description and cost estimate of concrete repair work. Both alternatives would benefit from the installation of downward opening weir gates at the intake structure effluent channels. The gates would allow proportional flow distribution between aeration tanks. Both alternatives will also be coated with 100% solids epoxy appropriate for wastewater service which has a design life of 50 years. Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

27 A new concrete structure would have a design life of 50 years but the projected lifespan of a rehabilitated structure is uncertain. The existing intake structure modifications to accommodate new mechanical bar screens are shown on Figure 3-2. A new intake structure will have a similar layout Cost Analysis The construction costs of the two intake structure alternatives are shown in Table 3-1. The construction cost of a new intake structure is estimated to be approximately $1,098,000 or approximately 5% more than the rehabilitation of the existing structure. The service life of a new structure is expected to be approximately 50 years but the projected lifespan of a rehabilitated structure is uncertain. Retrofitting the existing Intake Structure with new mechanical screens and appurtenances would also require modifications for necessary access to the equipment for operations and maintenance. 3.2 Grit Removal Alternatives If grit is not removed efficiently prior to aeration basins and other downstream treatment units, it can accumulate throughout the plant and effectively reduce available capacity of aeration tanks. If grit covers diffusers, oxygen transfer efficiencies will be reduced, limiting treatment performance and increasing energy consumption. Two alternatives were evaluated for grit removal. The first alternative includes construction of a grit chamber between the mechanical bar screens and aeration tanks. In today s market, there are two major types of grit removal systems: vortex grit chambers (including forced hydraulic vortex and vortex settlers), and aerated grit Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

28 chambers. Vortex type grit chambers generally offer better performance than conventional aerated chambers. Cost data for vortex type grit chambers were used for this study. A grit chamber cannot be used with the existing intake structure because of insufficient hydraulic head to overcome additional grit chamber head losses at the two-hour peak flow of MGD as illustrated in the Hydraulic Profile (Figure 3-3). According to information provided by grit chamber manufacturers, grit chambers have a guaranteed removal efficiency of 95% for 140 mesh (105 microns) grit, the equivalent to powder-fine sand. Klotz Associates contacted several references provided by Smith & Loveless, one of several vortex type grit chamber manufacturers. All contacted references indicated removal from 1.0 to 2.0 cubic yards of grit per week per MGD capacity (see Appendix C for grit removal system references information). The second alternative includes not installing a grit removal system but having aeration basins cleaned periodically. Manually cleaning basins can be difficult due to the matrix of piping on the tank floor. One option for manual grit removal is to leave enough water mixed with the grit so that the grit can be removed by a vactor truck. Another option involves lifting the diffusers off the floor. Fine bubble diffuser systems can be designed to allow mechanical lifting of the diffusers and piping. To achieve this, a swivel joint in the header piping is used as a hinge. This allows a front-end loader (bobcat) to access the basin floor and easily remove grit Cost Analysis The cost of constructing a new grit removal system is estimated to be approximately $550,000, including a 20% contingency. The present net worth of each alternative was calculated to determine the most cost effective approach for managing grit over Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

29 the 20-year life cycle of the facility. The capital cost and operations and maintenance (O&M) cost of Alternative 1 was compared to the life cycle cost of O&M over the life cycle of Alternative 2. Annual energy costs for Alternative 1 are estimated to be $5,000 as shown in Table 3-2. Table 3-3 shows the Present Net Worth Analysis of each of the grit removal alternatives. For purposes of this analysis, it was assumed that grit would be removed from aeration basins every other year at a cost of $62,200. This cost was obtained from a vendor providing this service using a vactor truck. As shown in Table 3-3, the net present worth of Alternative 2 is approximately $151,000 less than Alternative 1 over a 20-year life cycle. While a grit removal system costs more than regular grit removal from the aeration basins, the grit removal system has an advantage of reducing wear on plant equipment such as the return and waste activated sludge pumps. A grit removal system can be installed in the future as a stand-alone construction project if a new intake structure is constructed. 3.3 Aeration Basins Rehabilitation: The existing diffusers in aeration basins 1, 4 and 5 are fixed header medium bubble diffusers. Basins 2 and 3 utilize a combination of mechanical aerators and diffusers. GCA characterizes the existing diffusers in aeration basins 2 and 3 as medium bubble aeration. The EPA classifies coarse bubble as having a bubble diameter of 6 10 mm and fine bubble as having a bubble diameter of 2 5 mm. The diffusers in place at the Plant are no longer manufactured and so the actual bubble diameter is not known, but is likely similar to today s coarse bubble diffusers Required Air Flow Required Air Flow (RAF) calculations for actual and permit conditions were performed based on the TCEQ 217 requirements (see Appendix D for air flow Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

30 calculations). Required air flow (RAF) for fine and coarse bubble diffusers at various plant flow conditions is summarized as follows: Fine Bubble Diffusers SCFM Coarse Bubble Diffusers SCFM Basin No. 1: RAF at 5.5 MGD (actual AAF): 2,473 2,998 RAF at 9.25 MGD (permit AAF): 4,095 5,521 Basins Nos. 2 and 3: RAF at 5.5 MGD (actual AAF): 3,457 6,091 RAF at 9.25 MGD (permit AAF): 5,815 10,244 Basins Nos. 4 and 5: RAF at 5.5 MGD (actual AAF): 2,279 3,281 RAF at 9.25 MGD (permit AAF): 3,833 5, Basin No. 1 The diffusers in Basin 1 are more than 27 years old and many are inoperable. As a result, the basin has dead zones that do not receive the required oxygen. All the diffusers need to be replaced with either coarse or fine bubble diffusers. Alternative 1: Install Fine Bubble Diffusers Installing fine bubble diffusers will require filling in the conical base of the existing basin and constructing a concrete slab over the fill in order that the diffusers be installed on a flat surface. Fine bubble membranes require maintenance. Maintenance for fine bubble aeration includes draining the basin, scrubbing membranes by hand with a soft brush and removal of grit by vactor truck. Membrane manufacturers recommend cleaning membranes once a year to prevent any reduction in membrane oxygen transfer efficiency. In addition, after approximately 10 years of service, the membrane disks may need to be replaced. Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

31 Alternative 2: Install Coarse Bubble Diffusers Coarse bubble diffusers do not require filling in the tank conical section. This installation would also require a mixer because the coarse bubble diffusers cannot provide sufficient aeration in the center of the basin. As shown in Table 3-4, the net present worth of Alternative 1 is approximately $1,000,000 less than Alternative 2 over a 20-year life cycle. Fine bubble diffusers save 34% in annual Operation and Maintenance cost compared to coarse bubble aerators. Construction cost for Alternative 1 is $350,000 and the construction cost for Alternative 2 is $320, Basins No. 2 and 3 Basins 2 and 3 are being evaluated for fine bubble aeration compared to the existing mechanical and medium bubble aeration. The two alternatives are described below. Alternative 1: Install Fine Bubble Diffusers Renovating these two basins for fine bubble aeration requires installing fine bubble membranes and associated air piping at the bottom of the tank and demolishing the existing surface aerators and their concrete pedestals. In addition, in order to meet air requirements, the 12-inch air header must be replaced with a 16-inch air header. Again, maintenance cost for fine bubble aeration assumes that the basin is drained, membranes are scrubbed by hand with a soft brush and 2-inches of grit are removed by vactor truck. Membrane manufacturers recommend cleaning membranes once a year to prevent any reduction in membrane oxygen transfer efficiency. In addition, after approximately 10 years of service, the membrane disks may need to be replaced. Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

32 Alternative 2: Existing Aeration System Basins 2 and 3 are currently aerated with four 60 HP mechanical surface aerators, augmented by medium bubble aerators. The aerators and diffusers are approximately 30 years old. Based on discussions with Plant operators, the coarse bubble diffusers are only used during high BOD loading events. As shown in Table 3-5, the net present worth of Alternative 1 is more expensive than Alternative 2 because Alternative 2 has no capital cost. The mixers and their motors have exceeded their design life and can fail at any time. The basin has no redundancy if one of the mixers is inoperable. If the surface aerators are not replaced, Basins 2 and 3 do not have reliable aeration Basins No. 4 and 5 Basins 4 and 5 are currently aerated with medium bubble diffusers. The diffusers are more than 27 years old and many are inoperable as reported by Plant operators. All the diffusers need to be replaced with either coarse or fine bubble diffusers. Alternative 1: Install Fine Bubble Diffusers Alternative 1 includes replacing all medium bubble diffusers with fine bubble membrane diffusers and associated piping. Fine bubble aeration must consider maintenance costs. Maintenance cost for fine bubble aeration assumes that the basin is drained, membranes are scrubbed by hand with a soft brush and 2-inches of grit are removed by vactor truck. Membrane manufacturers recommend cleaning membranes once a year to prevent any reduction in membrane oxygen transfer efficiency. In Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

33 addition, after approximately 10 years of service, the membrane disks may need to be replaced. Alternative 2: Install Coarse Bubble Diffusers Alternative 2 involves replacing all existing diffusers with new fixed header coarse bubble diffusers including all submerged piping. Drop leg diffusers are not feasible in this basin because either a mixer or a new bridge with diffusers would be required to mix the interior of the basin. The existing air header provides sufficient air flow for either fine or coarse bubble service option. As shown in Table 3-6, the net present worth of Alternative 1 is approximately $420,000 less than Alternative 1 over a 20-year life cycle. Fine bubble aerators save 17% in annual Operation and Maintenance cost compared to coarse bubble aerators. The construction cost of Alternative 1 is $158,000 and the construction cost of Alternative 2 is $245, Aeration System Replacement Recommendations Based on the PNV cost analysis, Klotz Associates recommends all three basins be retrofitted with fine bubble aeration systems. Fine bubble diffusers transfer oxygen more efficiently than either the existing mechanical aerators or coarse bubble diffusers thereby reducing required blower capacity and energy use. The proposed layout of fine bubble diffusers for Aeration basins No. 1, 2, 3, 4 and 5 is shown on Figures 3-4, 3-5, and 3-6 respectively. Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

34 3.3.6 Blower Alternatives The blowers provide mixing and oxygen transfer for the activated sludge treatment process in the aeration basins. Three blower configuration alternatives were evaluated: Alternative 1 Alternative 1 includes replacement of the three existing 250 HP multistage blowers and two 75 HP blowers with four variable speed single stage turbo blowers with associated automatic controls and instrumentation. There would be one blower dedicated for each basin set with one additional blower for standby service for a total of four blowers. Separate headers for each basin permit each blower to use only the energy needed to aerate the basin, optimizing energy use. The standby blower can be used with any of the aeration tanks by constructing a common air distribution manifold with isolation valves. The blowers will each have a variable frequency drive (VFD) controlled by DO concentration in each basin measured by a DO probe. The blowers speed (and resulting power usage) will adjust based on the DO input signal from each individual basin. Alternative 2 Alternative 2 is based on the fact that the three existing 250 HP multistage blowers have sufficient aeration capacity for all five aeration basins based on the permitted flow without redundancy (see Appendix E for existing blowers curve and Appendix F for blower air headloss calculations). Considering that the 250 HP blowers were rebuilt in and have an expected design life of approximately 10 years, replacing or rebuilding these three blowers can be postponed until 2018, and another rebuild or replacement of the 250 HP blowers can be postponed until The 75 Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

35 HP blowers installed in 1984 do not have sufficient capacity for either one of the five aeration basins, and at least one blower must be replaced to meet TCEQ redundancy criterion. It is proposed that the two 75 HP blowers be replaced with a single multistage centrifugal blower comparable to the existing 250 HP blowers. Similar to Alternative 1, there would be one blower dedicated for each basin set with one additional blower for standby service for a total of four blowers. The standby blower can be used with any of the aeration tanks by constructing common air distribution manifold with isolation valves. Separate headers for each basin permit each blower to use only the energy needed to aerate the basin, optimizing energy use. Additional equipment in Alternative 2 includes DO control loops that automatically modulate blower intake valves for each blower (new and existing). Alternative 3 Alternative 3 involves connecting all three existing multi-stage centrifugal blowers and a new blower to the existing common manifold similar to the existing layout. Air flow to each basin can be controlled by either custom-fabricated orifice plates or by pressure sensors installed at each individual basin. The orifice plate throttles flow to the shallower basins to even flow distribution. The pressure sensors signal valves to close in order to evenly distribute air flow. Neither option offers energy savings because the blowers have to operate at full power to meet the air demands of the deepest basin while the outlets to the shallower basins are throttled. In order to realize energy savings from blowers, the basins with similar side-water depths will require their own header. The existing air headers for basins 1, 4 and 5 are correctly sized for either fine bubble or coarse bubble service. The air header for basins 2 and 3 will have to be replaced in order to provide sufficient air flow for fine bubble aeration. Switching to turbo blowers can further optimize energy savings because the blowers can vary air flow based on DO sensor readings. Table 3-7 Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

36 demonstrates that 45% power savings can be achieved using only the power needed to aerate each individual basin instead of running blowers at full power all the time in a single header configuration. Klotz Associates recommends individual headers for each basin depth in order to save money on energy Blower Cost Analysis The estimated construction cost for Alternative 1, replacement of existing blowers with new single stage centrifugal blowers, is summarized as follows: 250 HP Blowers $875,380 Remove existing 75 HP and 250 HP blowers $2,500 Control Panel for Blowers $44,275 Feeder Addition From MCC #1 $158,125 New MCC $94,875 New Precast Concrete MCC Building $64,400 Blower VFD Relocation (4 Units) $59,800 Subtotal $1,299,355 20% Contingency $259,871 Total Construction Cost $1,559,000 The estimated construction cost for Alternative 2, replacement of the existing 75 HP blowers with a new 250 HP multi-stage blower, similar to the existing 250 HP blowers is summarized as follows: Centrifugal Blower HP $112,413 Actuated Butterfly Valve $68,770 Control Panel for Blowers $26,450 Modifications to Existing MCC-2 $50,600 Subtotal $258,233 20% Contingency $51,647 Total Construction Cost $310,000 Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

37 A present worth analysis of each blower alternative was performed to determine the most cost effective alternative over a 20 year life cycle for the project. Table 3-7 shows the estimated annual energy cost of each blower alternative. As shown in Table 3-7, energy costs for the single stage turbo blowers is estimated to be approximately $170,000 per year less than Alternative 2. Taking into account this annual energy savings and the capital cost of each alternative, the Present Net Worth over a 20 year project life cycle was calculated, as shown in Table 3-8. As shown in Table 3-8, the Present Net Worth of Alternative 1 is $ 1,000,000 less expensive than Alternative 2, and is $3,600,000 less expensive than Alternative 3 over the 20 year life cycle of the project. This equates to a simple payback of approximately 8 years for Alternative Air Piping The existing 12-inch air piping connecting the blowers to Aeration Basins 2 and 3 was installed in 1984 for augmenting the surface aerators with diffusers receiving air from 75 HP blowers. The 12-inch line will generate excessive air head loss if utilized for the required air flow. The 12-inch piping must be replaced with 16-inch piping in order to install fine bubble aeration. The existing 18-inch air piping connecting blowers to Aeration Basins 4 and 5 and the existing 16-inch air piping connecting blowers to Aeration Basin 1 have sufficient capacity for the required air flow. 3.4 Filtration System Alternative 1 The existing Infilco Degremont Traveling Bridge Sand Filters were a part of the original plant construction and have exceeded their useful design life. Jestec Field Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

38 Services, Inc. conducted a field investigation of the filters to determine the scope of rehabilitation. The report is included in Appendix G. Filter rehabilitation will include replacing the filter media, upgrading the underdrain system, replacing backwash carriage components, replacing washwater launder troughs and mounting brackets, replacing festoon system cable and trolleys, sandblasting and repainting backwash carriage frame and sandblasting and painting carriage rails. Renovating the filters as a separate project will cost $692,000. A new carriage and carriage rails would cost an additional $100,000. See detailed cost estimate in Table 4-3. Alternative 2 Cloth media filters were evaluated as a possible filter replacement. Two AquaDiamond filters can be installed in the existing concrete basins and provide 14 MGD per filter, meeting 2-hour peak flow. Installing two new AquaDiamond Filters would cost $1,888,000 versus $554,000 for rehabilitating two of the existing media filters. The other media filters would have to remain in place to meet TCEQ redundancy requirements. Installing a third AquaDiamond filter in five years would cost approximately $974,000, meeting TCEQ redundancy requirements and allowing the remaining media filters to be removed. The total cost to retrofit three basins over 5 years with AquaDiamond filters is $2,862,000. Table 3-9 compares rehabilitating the existing media filters (Alternative 1) to retrofitting three basins with new AquaDiamond cloth media filters (Alternative 2). Over a 20 year life-cycle that includes operations and maintenance costs, the net present value of the two Alternatives are approximately equal (see Table 3-9). While the cloth media filters provide increased flow, improved filtration performance, reduced backwash and reduced maintenance, the current project budget makes the AquaDiamond filters cost prohibitive. Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

39 3.5 UV System The current system was designed to meet a disinfection standard of 200 fecal coliform per 100 ml based on a 30 day geometric mean with 10 mg/l TSS and the design UV dose to meet this was 22,000 µw/cm 2. The current discharge permit requirement is 35 enterococci per 100 ml on a 30 day geometric mean, and a maximum of 89 enterococci for any grab sample. Design criteria require a UV dose of 40,000 µw/cm 2 with a 10 mg/l TSS in order to ensure proper disinfection. The current system contains 1,104 lamps and is sufficient to meet the more stringent disinfection standard; however, the current system does not provide any system redundancy as required by TCEQ design criteria. It is recommended that the existing Trojan UV3000 Classic System be replaced with a Trojan UV 3000 Plus System. The following design values are recommended: Peak design flow of MGD UV transmittance: 65% minimum Total TSS: 12 mg/l Disinfection limit: 89 enterococci per 100 ml Design Dose: 39,260 µws/cm 2, bioassay validated Include self-cleaning feature Realize energy efficiencies The new UV system, with higher wattage bulbs, will treat the ADF with a single channel and peak 2-hour flow with two channels. The third channel can be standby capacity or used for future plant expansion. Layout of the proposed UV system is shown on Figure 3-7. Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

40 By replacing the existing UV system with the Trojan UV 3000 Plus, the new system will require the following: Total Number of Banks: 4 Number of Modules per Bank: 13 Number of Lamps per Module: 6 Total Number of UV Lamps: 312 (1,109 are currently used) Maximum Power Draw: 78 KW The estimated cost of a Trojan UV 3000 Plus system is approximately $1,000,000. If the UV upgrade were bid as a separate project, the project cost is estimated at $1,456,000. See Table 4-3 for a cost breakdown. 3.6 Actuated Slide Gates To improve plant operability, actuators will be installed at two locations. The two influent gates on the UV system and the two gates inside the clarifier splitter box will all be retrofitted with actuators. The actuators will be local-control with the option of connecting to the existing SCADA system. 3.7 Electrical Equipment Each of the facility upgrades that are proposed for the Blackhawk Wastewater Treatment Plant includes an electrical/instrumentation/control (EIC) cost factor. Provided below is a summarized description of each of these EIC factors: Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

41 3.7.1 Intake Structure With the installation of a new intake facility there will be a requirement to provide new power, control and instrumentation wiring to gate actuators, lighting, receptacles, screening equipment and potentially a new grit chamber. These interconnections will be made through the motor control center that is mounted in the Blower Room Actuated Slide Gates The gates installed in the existing flow splitting diversion structure are presently operated manually. Electric motor actuators will be added to these gates to assist the operators in making manual changes to the position of these gates Blowers Regardless of approach that is ultimately chosen for the renovation of the basin aeration system there will be a requirement for a considerable amount of demolition effort for the aeration equipment that will be replaced both at the aeration basins and within the Blower Room. With Aeration Alternative 1 there will be a requirement to install a new MCC2A for the new high speed aeration blower approach. There are multiple reasons for reaching this conclusion. The existing MCC2 is dated, it is in only a moderately good state of repair and the ampacity rating of the unit is marginal for the revised loads. From a constructability perspective it will also be beneficial to make this revision. It will be virtually impossible to make the Aeration Alternate 1 revisions unless a new MCC is installed. Lengthy disruptions in the aeration capabilities of the plant will occur unless there is an alternate source of MCC power available. Due to these constraints and also the lack of useable space within the Blower Room for a third Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

42 motor control center it is recommended that a new precast concrete building be constructed adjacent to the Blower Room to house the proposed MCC2A. A higher ampacity feeder from MCC 1 will also be required to power the proposed MCC2A and related electrical equipment. Spare conduits were installed during the electrical rehabilitation project that was completed some ten years ago to facilitate powering this new MCC. With Aeration Alternatives 2 and 3 we will be able to make modifications to the existing MCC2 to handle the revisions involved with the change from the two (2) existing 75 horsepower multi-stage centrifugal blowers to the one (1) 250 horsepower multi-stage centrifugal blower. With the recommendation for the use of various forms of high speed single stage aeration blowers in Aeration Alternative 1 there will be an involved use of variable frequency drives. The principal manufacturers of this type of equipment have designed their blowers to integrally house the associated variable frequency drives inside the blower enclosure. Some vendors include specially designed cooling systems to keep the VFDs cool. In light of the high degree of sophistication of VFDs and the extremely high air temperatures that these units can be subjected to while considering only the ambient temperate of the entering air it is recommended that these VFDs be relocated from the blower enclosures to the new electrical building. This will significantly enhance the life expectancy of these drives. Both of the aeration blower alternates will require a considerable amount of attention to the installation of conduit and wiring relating to the instrumentation, control valves, VFD relocations and power wiring. Typically the aeration blower alternates will each involve a locally mounted control panel furnished by the vendor. This panel will act as the centralized point of monitoring and control for the blowers that are installed. Regardless of the alternate Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

43 selected there will be a need for modifications to the existing SCADA system. These modifications will include updates to the system input/output (I/O) point count and the process graphics UV System The existing Trojan UV system operates at 208 volt, 3 phase. This operational voltage is provides through a locally mounted step down transformer (480 volt, 3 phase to 208 volt, 3 phase). The proposed Trojan UV system operates at 480 volt, 3 phase. Modifications will be made to the EIC area in this area to permit the existing UV system to continue in operation while the new UV system is installed thereby permitting the overall plant disinfection capabilities to continue during the construction phase. Motorized gate actuators will be installed on the inlet gates of the involved channels to assist the new control center and facility operators in gaining operational efficiency. The anticipated electrical load of the proposed UV disinfection system is virtually the same as the existing UV system. The existing emergency generator will therefore be capable of handling the UV system modifications of this project. 3.8 Recommended Improvements Klotz Associates recommends the following improvements to be incorporated in the final design: Intake Structure Construct a new intake structure with new mechanical bar screens including washer and conveyor, and control panel. Install effluent weir gates for volume proportional flow distribution between aeration tanks. The capital cost of the new Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

44 intake structure is approximately 5% higher than rehabilitation of the existing structure. The intake structure cost comparison is presented in Table 3-1. Diffusers Replace existing medium bubble aeration system and surface aerators with fine bubble diffused aeration system in all five basins. Blowers Replace three existing 250 HP blowers and two 75 HP blowers with four variable speed turbo blowers with associated piping, control and electrical modifications. The recommendation is based on the Present Net Value (PNV) life cycle cost analysis of two alternatives as presented in Table 3-8. The alternative has a simple payback of approximately 8 years. Filters: Refurbish the 1977 Infilco Degremont ABW traveling bridge filters based upon a field service report issued by Jack Jessop on October 20, UV System: Replace existing UV system with the Trojan UV 3000 Plus System or equivalent system by another. Actuated Slide Gates: Install electrical actuators on the existing isolation slide gates at the clarifier splitter structure and UV channel. The flow schematic for the recommended improvements is shown in Figure 3-8. Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

45 SECTION 4 COST ESTIMATES 4.1 Construction Cost Klotz Associates, Inc. prepared the opinions of probable construction cost for items identified during the 2010 Rehabilitation Study as well as additional items identified in July 2011 with GCA staff. The construction cost opinions were developed using historical bid data, estimated quantities, manufacturer s quotes, and contractor s estimates. All cost opinions include a 20% contingency. The summary of the opinions of cost are as follows: Description Option 1 - Original Scope of Work (2010 Study) Option 2 - Scope of Work including July 2011 Additional Items Estimated Cost of Construction $4,796,000 $6,447,000 The opinion of probable cost of the Original Scope of Work is presented in Table 4-1, and the cost opinion of the Original Scope of Work with additional items is presented in Table 4-2. Each of the options represents a comprehensive approach to rehabilitation of the Blackhawk Plant. Items included in each option are listed in Section 1.2 of this report. The major cost differences between the two options is the addition of new high efficiency single stage blowers and related electrical upgrades to further maximize energy efficiencies resulting in significant energy cost savings over the life of the project. As described in detail in Section 3 of this report, capital costs for fine bubble and coarse bubble diffuser systems are essentially equal. Replacing the existing multi-stage centrifugal blowers with single-stage centrifugal blowers results in a simple payback of approximately 8 years as a result of energy savings. Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

46 In November 2011, GCA requested Klotz Associates look at additional, less capital intensive alternatives for rehabilitation of the Blackhawk Plant, prioritizing needed improvements and analyzing the costs of individual stand-alone projects. Construction cost estimates for these stand-alone projects are shown in Tables 4-3, 4-4 and 4-5. Top Priority Items Package No. 1: Intake structure replacement with a total construction cost of $1,098,000. Package No. 2 is UV system replacement and traveling bridge filter rehabilitation with a total construction cost of $2,160,000. See Table 4-3 for a cost estimate summary. Note that Package 1-B to Rehabilitate Existing Intake Structure is approximately the same cost as building a new intake structure. Second Priority Items Package No. 3: Aeration tanks aeration system replacement stand-alone projects (Table 4-4) are as follows: - Package No. 3-1 Aeration Basin No. 1 construction cost: $585,000 - Package No. 3-2 Aeration Basins Nos. 2 and 3 construction cost: $817,000 - Package No. 3-3 Aeration Basins Nos. 4 and 5: $389,000 - Total construction cost for Package 3: $1,7891,000. Package No. 4 Blowers replacement including new control system and instrumentation with a total construction cost of $1,446,000. See Table 4-5 for a cost estimate summary. Packages Nos. 3 and 4 can be combined into a single package with a total cost of $3,237,000. Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

47 SECTION 5 PHASED APPROACH TO IMPLEMENTING BLACKHAWK WWTP REHABILITATION 5.1 Construction Packages 1 and 2 Due to potential budgetary constraints, the GCA wishes to consider a phased approach to improvements to Blackhawk WWTP. Construction packages 1 and 2 are high priority improvements required in the near term to ensure reliability of the Blackhawk WWTP. Construction Package 1 includes constructing a new intake structure with two mechanical bar screens including washer, conveyor, and control panel. Work also includes installing effluent weirs for volume proportional flow distribution between aeration tanks. The total construction cost for Construction Package 1 is $1,098,000. Construction Package 2 includes replacing the UV system and rehabilitating the traveling bridge filter. The UV system will be upgraded from Trojan UV 3000 to Trojan UV 3000 Plus. Filter rehabilitation will include replacing the filter media, upgrading the underdrain system, replacing backwash carriage components, replacing washwater launder troughs and mounting brackets, replacing festoon system cable and trolleys, sandblasting and repainting backwash carriage frame and sandblasting and painting carriage rails. The total construction cost for Construction Package 2 is $2,160,000. See Table 4-3 for a cost estimate summary. 5.2 Construction Packages 3 and 4 Construction Package 3 encompasses aeration tank system replacement which includes removing mechanical aerators and coarse bubble diffusers and replacing Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

48 them with fine bubble aeration systems in all five basins. Work also includes filling in the conical base of Basin 1, adding a blower to meet air requirements for Basins 2 and 3, adding new air piping to Basins 2 and 3, installing all related instrumentation and SCADA modifications. A cost estimate is presented in Table 4-4 and is summarized as follows: Package 3-1 Aeration Basin No. 1: $585,000 Package 3-2 Aeration Basins Nos. 2 and 3: $817,000 Package 3-3 Aeration Basins Nos. 4 and 5: $389,000 The total construction cost of Package 3 is $1,791,000. Construction Package No. 4 includes replacing the centrifugal blowers with singlestage turbo blowers including variable frequency drives, installing a new control and instrumentation system and constructing a new precast concrete MCC building for a total construction cost of $1,446,000. See Table 4-5 for a cost estimate summary. Packages 3 and 4 can be combined into a single package with a total cost of $3,237,000. Construction Packages 3 and 4 will be constructed at a later date. Klotz Associates Project No March Gulf Coast Waste Disposal Authority Blackhawk WWTP PER

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58 Table 2-1 Plant Capacity Evaluation per TCEQ Requirements Treatment Unit TCEQ Regulations Required Capacity Actual Capacity Percent of Required Organic loading for conventional activated sludge process with nitrification when reactor % temperature exceed 15 C (lbs of BOD5/day/1,000 cf) Aeration basin must have a minimum freeboard at peak flow of (inches) Aeration Basin % Aeration Basins 2 and % Aeration Basins 4 and % Clarifier Clarifier Clarifier Clarifier Clarifier Weir loading must not exceed (gpd per linear feet of weir at peak flow) Clarifier minimum side water depth (SWD) in feet Clarifier must have a minimum freeboard at peak flow of (inches) Maximum clarifier overflow rates at 2-hr peak flow (gpd/sf) Minimum clarifier detention time at 2-hr peak flow (hours) 30,000 21, % % % % % Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authroity Blackhawk WWTP Rehabilitation Study

59 Table 2-2 Flow Data Summary January July 2011 Annual Average Flow (AAF) Max. Monthly Average Flow (MMAF) Max. Daily Flow (MDF) Peak Flow (PF) MGD MGD MGD GPM , , , , , ,167 Average ,167 Permit Design Flow 9.25 N/A N/A 19,270 MDF/AAF PF/AAF MMAF/AAF Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation Study

60 Table 2-3 Plant Raw Influent Grab Sampling Data Summary of Raw Influent Data Annual Average Daily Concentration Standard Deviation Annual Average Daily Concentration plus one standard deviation Influent BOD (1) 182 mg/l 105 mg/l 286 mg/l Ammonia-Nitrogen (2) 27 mg/l 3.3 mg/l 31 mg/l Total Suspended Solids (3) 192 mg/l 84.9 mg/l 277 mg/l Notes: (1) Grab samples data collected from Jan 2009 to June 2011 (2) Grab samples data from Jan 2010 to June 2011 (3) Grab samples data collected from Jan 2010 to Dec 2010 Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

61 Table 2-4 Plant Raw Influent 24-hour Composite Sampling Data Date Ammonia BOD 5 TSS 8/24/ mg/l 268 mg/l 288 mg/l 8/25/ mg/l 156 mg/l 180 mg/l 8/26/ mg/l 288 mg/l 316 mg/l 8/29/ mg/l 248 mg/l 296 mg/l 8/30/ mg/l 112 mg/l 276 mg/l 8/31/ mg/l 187 mg/l 157 mg/l 9/1/ mg/l 199 mg/l 174 mg/l 9/2/ mg/l 202 mg/l Average 25.9 mg/l 208 mg/l 236 mg/l Standard Deviation 4.1 mg/l 63 mg/l 64 mg/l Average+ Standard Deviation 30.1 mg/l 272 mg/l 300 mg/l Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

62 Table 3-1 Intake Structure Construction Cost Comparison Alternative 1: New Intake Structure Alternative 2: Intake Structure Rehabilitation 1 General Requirements $40,000 1 General Requirements $30,000 2 Concrete for New Intake Structure $150,000 2 Repair Concrete on Headworks Structure * $192,484 4 Concrete for Flow Splitterbox $9,600 3 Grating and Platform $2,484 5 Grating and Platform $2,484 4 Weir Gates $40,392 6 Mechanical Bar Screen $244,663 5 Mechanical Bar Screen $276,575 7 Enclosure $26,450 6 Enclosure $26,450 8 Washer/Compactor and Shaftless Auger Conveyor $99,188 7 Washer/Compactor and Shaftless Auger Conveyor $99, " DIP to Basin 1 $16,632 8 Wall Liner - 100% Solids Epoxy $81, " DIP to Basins 2, 3, 4 & 5 and influent sump $47,628 9 Diversion Pumping $50, " push-on DIP to redirect force main to new intake $10, Pulsar Flow Meter $4, " push-on DIP to redirect force main to new intake $7, Headworks/ Bar Screen Electrical Work $41, " Tee $23,040 Subtotal $845, " Tee $3,550 20% Contingency $169, " Tee $1,426 Total Construction Cost $1,015, Wall Liner - 100% Solids Epoxy $81, Weir Gates $40, Diversion Pumps and Piping $10,000 *See Appendix H 19 Slide Gates $53, Headworks/ Bar Screen Electrical Work $41, Pulsar Flow Meter $4,140 Subtotal 20% Contingency Total Construction Cost $914,321 $182,864 $1,098,000 Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

63 Table 3-2 Annual Energy Costs for Grit Removal Operation for Alternative 1 Power cost $0.10 (1) Equipment Rated HP Voltage Amps Power Factor Kw Hrs Cost per day Annual Energy Costs Alternative 1 Grit Mixer (1) $6.1 $2,300 Grit Washer (1) $1.4 $600 Grit Pump Total (1) $6.3 $2,300 $5,000 Notes: (1) Information provided by GCA Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

64 Table 3-3 Net Present Worth Analysis of Grit Removal Alternatives Inflation rate 3.50% Life span 20 ALTERNATIVE 1 Equipment Capital Cost ALTERNATIVE 2 $528,114 $0 Annual Energy Annual O & M Total Annual Costs Costs Costs Total Annual Costs (1) $528,114 Annual Expense $5,000 $1,600 $6,600 $62,200 Net Present Value (2) $601,000 $450,000 Notes: (1) Annual cost of grit removal using vactor truck (2) = (1+ ) k = inflation rate j = year in which expense occurs n = number of years Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

65 Table 3-4 Present Net Value Comparison of Fine Bubble vs Coarse Bubble Aeration in Aeration Basin 1 Alternative 1: Fine Bubble Diffusers Total Cost Alternative 2: Coarse Bubble Diffusers Total Cost Mechanical Equipment Mechanical Equipment Fine Bubble Diffusers $210,833 Coarse Bubble Diffusers $295,000 Basin Modifications $139,000 Mixer - 20 HP $25,000 Total Capital Cost $350,000 Total Capital Cost $320,000 Operations and Maintenance Operations and Maintenance Annual Maintenance Cost (3) $12,190 Annual Maintenance Cost $1,000 Annual Power Cost $134,330 Annual Power Cost $196,049 Total O&M Cost $147,000 Total O&M Cost $198,000 Lifespan of Equipment (years) (3) 20 Lifespan of Equipment (years) 20 Inflation Rate 3.5% Inflation Rate 3.5% Net Present Value of Maintenance $191,000 Net Present Value of Maintenance $15,000 Net Present Value of Power Cost $1,910,000 Net Present Value of Power Cost $2,787,000 Total Present Net Value including Capital Cost, Power Cost and Maintenance Cost $2,101,000 Total Present Net Value including Capital Cost, Power Cost and Maintenance Cost $3,122,000 (1) Net Present Value Formula: = (1+ ) k = inflation rate j = year in which expense occurs n = number of years (2) Power cost evaluated based on multi-stage centrifugal blowers with intake air valve controls and dedicated headers to each aeration basin. (3) A cost of $24,500 is included in year 10 for membrane replacement. Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

66 Table 3-5 Present Net Value Comparison of Fine Bubble vs Existing Surface Aerators in Aeration Basins 2 and 3 Alternative 1: Fine Bubble Diffusers Total Cost Alternative 2: Coarse Bubble Diffusers Total Cost Mechanical Equipment Mechanical Equipment Fine Bubble Diffusers $210,833 Existing Surface Aerators and Coarse Bubble Diffusers Capital Cost $0 16-inch DIP air header $93,600 Total Capital Cost $305,000 Operations and Maintenance Operations and Maintenance Annual Maintenance Cost (5) $19,442 Annual Maintenance Cost $10,000 Annual Power Cost $110,062 Annual Power Cost for Mechanical Aerators (3) $117,566 Total O&M Cost $130,000 Total O&M Cost $128,000 Lifespan of Equipment (years) (5) 20 Lifespan of Equipment (years) (4) 20 Inflation Rate 3.5% Inflation Rate 3.5% Net Present Value of O&M $306,000 Net Present Value of O&M $143,000 Net Present Value of Power Cost $1,565,000 Net Present Value of Mechanical Aerator Power Cost (3) $1,671,000 Total Present Net Value including Capital Cost, Power Cost and Maintenance Cost $2,270,000 Total Present Net Value including Capital Cost, Power Cost and Maintenance Cost $1,814,000 (1) Net Present Value Formula: = (1+ ) k = inflation rate j = year in which expense occurs n = number of years (2) Power cost evaluated based on multi-stage centrifugal blowers with intake air valve controls and dedicated headers to each aeration basin. (3) The power cost of coarse bubble diffusers was excluded because it is assumed they are not used on a regular basis, but only as needed. (4) Mixers and motors are beyond their design life; there is no presumption of reliability going forward. (5) A cost of $40,960 is included in year 10 for membrane replacement. Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

67 Table 3-6 Present Net Value Comparison of Fine Bubble vs Coarse Bubble Diffusers in Aeration Basins 4 and 5 Alternative 1: Fine Bubble Diffusers Total Cost Alternative 2: Coarse Bubble Diffusers Total Cost Mechanical Equipment Mechanical Equipment Fine Bubble Diffusers Capital Cost $158,000 Coarse Bubble Diffusers Capital Cost $245,000 Operations and Maintenance Operations and Maintenance Annual Maintenance Cost (3) $12,486 Annual Maintenance Cost $1,000 Annual Power Cost $130,699 Annual Power Cost $167,005 Total O&M Cost $144,000 Total O&M Cost $168,000 Lifespan of Equipment (years) (3) 20 Lifespan of Equipment (years) 20 Inflation Rate 3.5% Inflation Rate 3.5% Net Present Value of Maintenance $198,000 Net Present Value of Maintenance $15,000 Net Present Value of Power Cost $1,858,000 Net Present Value of Power Cost $2,374,000 Total Present Net Value including Capital Cost, Power Cost and Maintenance Cost $2,214,000 Total Present Net Value including Capital Cost, Power Cost and Maintenance Cost $2,634,000 (1) Net Present Value Formula: = (1+ ) k = inflation rate j = year in which expense occurs n = number of years (2) Power cost evaluated based on multi-stage centrifugal blowers with intake air valve controls and dedicated headers to each aeration basin. (3) A cost of $28,224 is included in year 10 for membrane replacement. Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

68 Table 3-7 Annual Energy Costs for Blower Operation for Alternatives 1, 2 and 3 Power cost $0.10 (1) Rated HP Voltage HP Motor Efficiency Kw Hrs Cost Annual Energy Costs Equipment Alternative 1 High Speed Turbo Blower (Basin 1) (2) 24 $126.2 $46,078 High Speed Turbo Blower (Basins 2 and 3) (2) 24 $227.3 $82,957 High Speed Turbo Blower (Basins 4 and 5) (2) 24 $224.6 $81,994 Total $211,028 Alternative 2 Existing Aeration Blower #1 (Basin 1) (3) $ ,330 Existing Aeration Blower #2 (Basins 4 & 5) (3) $ ,699 New Multi-Stage Centrifugal Blower (Basins 2 and 3) Total (3) $ ,062 $375,091 Alternative 3 Fine Bubble Aeration Basin 1 Power Cost (3) (4) 24 $497.3 $181,527 Fine Bubble Aeration Basins 2 and 3 Power Cost (3) (4) 24 $497.3 $181,527 Fine Bubble Aeration Basin 4 and 5 Power Cost (3) (4) 24 $497.3 $181,527 $544,580 Annual Energy Savings for a Dedicated Air Header 45% Notes: (1) Information provided by GCA (2) Wire to Air Power@ Design Conditions provided by High Speed Turbo Blower Manufacturer (3) Information provided by manufacturer (4) HP x = KW Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

69 Table 3-8 Net Present Worth Analysis of Blowers Replacement Inflation rate 3.50% Life span 20 Rebuilt cost of existing blowers $98,068 (3) Alternative 1 Equipment Capital Cost $1,559,000 YAnnual Energy Costs Annual O & M Costs (3) Total Annual Costs $1,559,000 $211,028 Net Present Value (4) $1,600 $212,628 $4,427,000 Year Net Present Value (4) Annual Energy Costs Annual O & M Costs Exist. Blowers (1) Alternative 2 Annual O & M Costs New Blowers (2) Total Annual O & M Costs Equipment Capital Cost Rebuilt Costs Exist Blowers (3) $310,000 Total Annual Costs 0 $310,000 1 $375,091 $4,304 $1,000 $5,304 $9,807 $390,202 $5,469,000 Year Net Present Value (4) Annual Energy Costs Annual O & M Costs Exist. Blowers (1) Alternative 3 Annual O & M Costs New Blowers (2) Total Annual O & M Costs Equipment Capital Cost Rebuilt Costs Exist Blowers (3) $310,000 Total Annual Costs 0 $310,000 1 $544,580 $4,304 $1,000 $5,304 $9,807 $559,691 $7,986,000 Notes: (1) Calculated based on the information provided by GCA: average annual maintenance costs during (2) Manufacturer's information (3) Rebuilt costs adjusted for inflation (4) = (1+ ) k = inflation rate j = year in which expense occurs n = number of years Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

70 Table 3-9 Engineer's Opinion of Probable Construction Cost for Infilco Degremont ABW Filter Renovation Alternative 1: Rehabilitate ABW Media Filters Units Quantity Total Unit Price Total Cost Alternative 2: Install AquaDiamond Filters Units Quantity Total Unit Price Total Cost Mechanical Equipment Mechanical Equipment Rehabilitate 2 ABW Filters LS 1 $553,380 $553,380 Install 2 AquaDiamond Filters in Existing Basins LS 1 $2,611,570 $2,612,000 Rehabilitate 3 ABW Filters in 5 Years (assume 3.5% inflation) LS 1 $1,026,161 $1,026,161 Replace piping, demolish splitter box and raise weirs LS 1 $250,000 $250,000 Total Capital Cost $1,580,000 Total Capital Cost $2,862,000 Operations and Maintenance (2) Operations and Maintenance (2) Annual Maintenance Cost Yr 1 $4,725 $4,725 Annual Maintenance Cost Yr 1 $1,032 $1,032 Annual Power Cost Yr 1 $14,858 $14,858 Annual Power Cost Yr 1 $2,717 $2,717 Lifespan of Equipment (years) 20 Lifespan of Equipment (years) 20 Inflation Rate 3.5% Inflation Rate 3.5% Net Present Value of O&M $426,000 Net Present Value of O&M $161,000 Net Present Value of Power Cost $212,000 Net Present Value of Power Cost $39,000 Total Present Net Value including Capital Cost, Power Cost and Maintenance Cost $3,244,000 Total Present Net Value including Capital Cost, Power Cost and Maintenance Cost $3,062,000 (1) Net Present Value Formula: = (1+ ) k = inflation rate j = year in which expense occurs n = number of years (2) Power and maintenance cost provided by Aqua Aerobics. Assumes 0.11 KW-hr. Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation Study

71 Table 4-1 Engineer's Opinion of Probable Cost - Original Scope Description Units Quantity Total Unit Price General Requirements Total Line Item Price 1 Other General Requirements (5% of Total Cost) LS 1 $250,000 $250,000 Demolition $250,000 1 Demolish Mechanical Aerators LS 1 $25,000 $25,000 2 Demolish concrete aerator supports LS 1 $25,000 $25,000 3 Remove existing 75HP blowers EA 2 $500 $1,000 4 Demolish Aeration Basin 1 walls LS 1 $10,000 $10,000 Concrete $61, " slab in Basin 1 CY 279 $500 $139,500 Total Cost of Concrete Intake Structure Rehabilitation 1 $139,500 Repair and Line Concrete on Headworks Structure including Wall Liner LS 1 $192,484 $192,484 2 Grating SF 200 $12 $2,484 3 Weir Gates EA 3 $13,464 $40,392 4 Wall Liner - 100% Solids Epoxy SF 4, $14 $61,920 5 Flow by-pass piping and pumps MO 2 $26,400 $52,800 Mechanical Upgrades $350,080 1 Mechanical Bar Screen EA 2 $122,331 $244,663 2 Enclosure EA 2 $13,225 $26,450 3 Washer/Compactor and Shaftless Auger Conveyor EA 1 $99,188 $99,188 4 Centrifugal Blower HP EA 1 $112,413 $112,413 5 Actuated Butterfly Valve EA 4 $17,193 $68,770 6 Control Panel for Blowers EA 1 $26,450 $26,450 7 Fine Bubble Diffusers LS 1 $581,900 $581, " DIP (flanged) for air from Blowers to Basins 2 and 3 LF 170 $380 $64, " DIP (push-on) for air from Blowers to Basins 2 and 3 LF 200 $144 $28, Refurbish Infilco Degremont Media Filters LS 1 $553,380 $553, Replace Trojan UV System LS 1 $1,016,606 $1,016, Electric Actuators EA 2 $7,935 $15,870 Electrical and Instrumentation Total Cost for General Requirements Total Cost for Intake Structure Rehabilitation Total Cost for Mechanical Items $2,838,953 1 UV System Modifications (w/o Gate Actuators) LS 1 $63,250 $63,250 2 Diversion Structure Gates (w/o Actuators) LS 1 $50,600 $50,600 3 Electrical Demolition For Aeration Basins LS 1 $31,625 $31,625 4 Headworks / Bar Screen / Grit Chamber LS 1 $41,745 $41,745 5 Modifications to Existing MCC-2 LS 1 $50,600 $50,600 6 SCADA Modifications LS 1 $50,600 $50,600 7 Pulsar Flow Meters EA 2 $2,070 $4,140 8 Air Flow Meters EA 3 $3,680 $11,040 9 Dissolved Oxygen Sensors LS 1 $14,375 $14,375 Total Cost for Electrical Subtotal 20% Contingency Total construction cost $317,975 $3,957,508 $791,502 $4,750,000 Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation Study

72 Table 4-2 Engineer's Opinion of Probable Construction Cost - Including Alternatives General Requirements Units Quantity Total Unit Price Total Line Item Price 1 Other General Requirements (5% of Total Cost) LS 1 $347,500 $347,500 Demolition $347,500 1 Demolish Mechanical Aerators LS 1 $50,000 $50,000 2 Demolish concrete aerator supports LS 1 $25,000 $25,000 3 Remove existing 75HP and 250 HP blowers EA 5 $500 $2,500 4 Demolish walls in Aeration Basin 1 LS 1 $10,000 $10,000 Concrete $87,500 1 Concrete for New Intake Structure CY 250 $600 $150,000 2 Concrete for Flow Splitterbox CY 16 $600 $9, " slab in Basin 1 CY 279 $500 $139,500 New Intake Structure Appurtenances $299,100 1 Grating SF 200 $12 $2, " DIP to Basin 1 LF 75 $222 $16, " DIP to Basins 2, 3, 4 & 5 and influent sump LF 147 $324 $47, " push-on DIP to redirect force main to new intake LF 50 $209 $10, " push-on DIP to redirect force main to new intake LF 50 $144 $7, " Tee EA 2 $11,520 $23, " Tee EA 1 $3,550 $3, " Tee EA 1 $1,426 $1,426 9 Wall Liner - 100% Solids Epoxy SF 4,300 $17 $71, Weir Gates EA 3 $13,464 $40, Slide Gates EA 4 $13,464 $53,856 Mechanical Upgrades Description Total Cost of General Items Total Cost of Demolition Total Cost of Concrete Total Cost of New Intake Structure Appurtenances $277,855 1 Mechanical Bar Screen EA 2 $122,331 $244,663 2 Enclosure EA 2 $13,225 $26,450 3 Washer/Compactor and Shaftless Auger Conveyor EA 1 $99,188 $99, HP Blowers EA 4 $218,845 $875,380 5 Control Panel for Blowers EA 1 $44,275 $44,275 6 Fine Bubble Diffusers LS 1 $632,500 $632, " DIP (flanged) for air from Blowers to Basins 2 & 3 LF 170 $380 $64, " DIP (push-on) for air from Blowers to Basins 2 & 3 LF 200 $144 $28,750 9 Refurbish Infilco Degremont Media Filters LS 1 $553,380 $553, Replace Trojan UV System LS 1 $1,055,091 $1,055, Install Electric Actuators EA 4 $9,522 $38,088 Total Cost of Mechanical Upgrades $3,662,279 Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation Study

73 Table 4-2 Engineer's Opinion of Probable Construction Cost - Including Alternatives Electrical and Instrumentation Description Units Quantity Total Unit Price Total Line Item Price 1 UV System Modifications (w/o Gate Actuators) LS 1 $63,250 $63,250 2 Diversion Structure Gates (w/o Actuators) LS 1 $50,600 $50,600 3 Electrical Demolition For Aeration Basins LS 1 $31,625 $31,625 4 Headworks / Bar Screen / Grit Chamber LS 1 $41,745 $41,745 5 Feeder Addition From MCC #1 LS 1 $158,125 $158,125 6 New MCC LS 1 $94,875 $94,875 7 New Precast Concrete MCC Building LS 1 $64,400 $64,400 8 Blower VFD Relocation (4 Units) LS 1 $59,800 $59,800 9 Aeration Control Component Installation LS 1 $46,000 $46, SCADA Modifications LS 1 $57,500 $57, Pulsar Flow Meters EA 2 $2,070 $4, Air Flow Meters EA 3 $3,680 $11, Dissolved Oxygen Sensors LS 1 $14,375 $14,375 Total Cost for Electrical Subtotal 20% Contingency Total Construction Cost $697,475 $5,371,709 $1,074,342 $6,447,000 Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation Study

74 Table 4-3 Engineer's Opinion of Probable Construction Cost - Packages 1 and 2 Package 1-A: New Intake Structure General Requirements Other General Requirements Diversion Pumping Concrete Concrete for New Intake Structure Concrete for Flow Splitterbox General Requirements Other General Requirements Diversion Pumping Concrete Cost to Rehabilitate Existing Structure New Intake Structure Appurtenances Grating Wall Liner - 100% Solids Epoxy Weir Gates Description New Intake Structure Appurtenances Grating 24" DIP to Basin 1 30" DIP to Basins 2, 3, 4 & 5 and influent sump 20" push-on DIP to redirect force main to new intake 14" push-on DIP to redirect force main to new intake 30" Tee 20" Tee 16" Tee Wall Liner - 100% Solids Epoxy Weir Gates Slide Gates Mechanical, Electrical and Instrumentation Mechanical Bar Screen Enclosure Washer/Compactor and Shaftless Auger Conveyor Headworks / Bar Screen Electrical Work Pulsar Flow Meters Package 1-B: Rehabilitate Existing Intake Structure Description Mechanical, Electrical and Instrumentation Mechanical Bar Screen Enclosure Washer/Compactor and Shaftless Auger Conveyor Headworks / Bar Screen Electrical Work Pulsar Flow Meters Units Quantity Total Unit Price Total Line Item Price LS 1 $40,000 $40,000 MO 1 $20,000 $10,000 Total Cost of General Items $50,000 CY 250 $600 $150,000 CY 16 $600 $9,600 Total Cost of Concrete $159,600 SF 200 $12 $2,484 LF 75 $222 $16,632 LF 147 $324 $47,628 LF 50 $209 $10,440 LF 50 $144 $7,200 EA 2 $11,520 $23,040 EA 1 $3,550 $3,550 EA 1 $1,426 $1,426 SF 4,300 $19 $81,889 EA 3 $13,464 $40,392 EA 4 $13,464 $53,856 Total Cost of New Intake Structure Appurtenances $288,536 EA 2 $122,331 $244,663 EA 2 $13,225 $26,450 EA 1 $99,188 $99,188 LS 1 $41,745 $41,745 EA 2 $2,070 $4,140 Total Cost of Mechanical, Electrical and Instrumentation Subtotal 20% Contingency Total Construction Cost Units Quantity Total Unit Price $416,185 $914,321 $182,864 $1,098,000 Total Line Item Price LS 1 $30,000 $30,000 MO 2.5 $20,000 $50,000 Total Cost of General Items $80,000 LS 1.00 $192,484 $192,484 Total Cost of Concrete $192,484 SF 200 $12 $2,484 SF 4,300 $19.04 $81,889 EA 3 $13,464 $40,392 Total Cost of New Intake Structure Appurtenances $124,765 EA 2 $138,288 $276,575 EA 2 $13,225 $26,450 EA 1 $99,188 $99,188 LS 1 $41,745 $41,745 EA 2 $2,070 $4,140 Total Cost of Mechanical, Electrical and Instrumentation Subtotal 20% Contingency Total Construction Cost $448,098 $845,347 $169,069 $1,015,000 Package 2-1: Rehabilitate Traveling Bridge Filters Description Units Quantity Total Unit Price Total Line Item Price General Requirements 1 General Requirements LS 1 $30,000 $30,000 2 Hauling Debris LS 1 $2,500 $2,500 Total Cost of General Items $32,500 Mechanical Upgrades ABW Filter Renovation: replace filter media, upgrade underdrain system, replace 2 backwash carriage components, replace launder trough and mounting brackets, replace, sandblast and repaint backwash carriage frame and carriage rails. LS 1 $553,380 $553,380 Total Cost of Mechanical Upgrades Subtotal 20% Contingency Total Construction Cost $553,380 $585,880 $117,176 $704,000 Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation Study

75 Table 4-3 Engineer's Opinion of Probable Construction Cost - Packages 1 and 2 Package 2-2: Rehabilitate UV System Description Units Quantity Total Unit Price Total Line Item Price General Requirements 1 Other General Requirements LS 1 $60,000 $60,000 2 Concrete for Channel Retrofit CY 28 $550 $15,400 Total Cost of General Items $75,400 Mechanical Upgrades 3 Replace Trojan UV System LS 1 $1,055,091 $1,055,091 4 Install Electric Actuators EA 2 $9,522 $19,044 Total Cost of Mechanical Upgrades $1,074,135 Electrical and Instrumentation 5 UV System Modifications (w/o Gate Actuators) LS 1 $63,250 $63,250 Total Cost for Electrical Subtotal 20% Contingency Total Construction Cost Total Construction Cost for Package 2 $63,250 $1,212,785 $242,557 $1,456,000 $2,160,000 Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation Study

76 Table 4-4 Engineer's Opinion of Probable Cost - Packages 3-1, 3-2, 3-3 Package 3-1: Aeration Basin 1 Aeration System Replacement Description Units Quantity Total Unit Price Total Line Item Price General Requirements LS 1 $46,500 $46,500 Fine Bubble Diffusers LS 1 $210,834 $210,834 Aeration Control Component installation LS 1 $18,400 $18,400 Demolish walls in Aeration Basin 1 LS 1 $20,000 $20,000 8" slab in Basin 1 CY 300 $500 $150,000 Electrical demolition for aeration basins LS 1 $13,335 $13,335 Air flow meters EA 1 $3,680 $3,680 DO Sensors EA 1 $4,792 $4,792 SCADA Modifications LS 1 $19,933 $19,933 Subtotal 20% Contingency Total $487,474 $97,495 $585,000 Package 3-2: Aeration Basins 2 & 3 Aeration System Replacement Description Units Quantity Total Unit Price Total Line Item Price General Requirements LS 1 $46,500 $46, inch DIP (flanged) for air from blowers LF 170 $546 $92, inch DIP (push-on) for air from blowers LF 200 $207 $41,400 Demolish Mechanical Aerators LS 1 $50,000 $50,000 Demolish Concrete Aerator Supports LS 1 $25,000 $25,000 Fine Bubble Diffusers LS 1 $210,833 $210, HP Turbo Blower EA 1 $218,845 $218,845 Control Panel for Blower EA 1 $56,008 $56,008 Aeration Control Component installation LS 1 $17,633 $17,633 Electrical demolition for aeration basins LS 1 $13,335 $13,335 Air flow meters EA 1 $3,680 $3,680 DO Sensors EA 1 $4,792 $4,792 SCADA Modifications LS 1 $19,933 $19,933 Subtotal 20% Contingency Total $800,822 $16,016 $817,000 Package 3-3: Aeration Basins 4 & 5 Aeration System Replacement Description Units Quantity Total Unit Price Total Line Item Price General Requirements LS 1 $24,500 $24,500 Fine Bubble Diffusers LS 1 $228,800 $228,800 Aeration Control Component installation LS 1 $23,276 $23,276 Electrical demolition for aeration basins LS 1 $13,915 $13,915 Air flow meters EA 1 $4,416 $4,416 DO Sensors EA 1 $5,750 $5,750 SCADA Modifications LS 1 $23,920 $23,920 Subtotal 20% Contingency Total Total Construction Cost for Package 3 $324,577 $64,915 $389,000 $1,791,000 Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

77 Table 4-5 Engineer's Opinion of Probable Construction Cost - Package 4 Package 4: Blower Replacement including Control System & Instrumentation Description Total Line Item Price General Requirements $60,000 Remove Existing 75 HP and 250 HP Blowers $2, HP blowers $686,378 Control Panel for Blowers $46,288 Feeder Addition from MCC #1 $181,844 New MCC $94,875 New Precast Concrete MCC Building $64,400 Blower VFD Relocation (4 units) $68,770 Subtotal 20% Contingency Total $1,205,054 $241,011 $1,446,000 Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

78 APPENDICES

79 Appendix A TPDES Permit

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130 Appendix B Influent Structure Structural Evaluation Report

131 September 8, 2011 PEI Job # Alexander V. Kuzovkov, P.E. Project Manager Klotz and Associates 1160 Dairy Ashford, Suite 500 Houston, Texas Re: Structural evaluation of the Blackhawk WWPP influent structure, in Friendswood. Alex, Paul Engineeringg Inc. has completed the structural evaluation of our observations at the Blackhawk WWP influent structure in Friendswood, Texas. PEI was hired to determine if the existing influent structure was repairable or would need to be replaced. Influent Structure and its description: PEI personnel made a site inspection of the influent structure on August 4, We found that all of the walls had extensive corrosion and deterioration of the concrete along the flow line elevation. Fig s. 1-8 show different t views of the walls showing various locations of corrosion. Fig. 1 Exterior walll in third chamber from stairs. 1

132 From our investigation we determined that the structure was built in 1984 and originally had a 20 mil coal tar epoxy liner on it which now appears to have corroded away. Fig. 2 - View of exterior wall in thirdd chamber from stairs. Fig. 3 View of damage to exterior wall in n first chamber by the stairs. 2

133 Fig. 4 - View of separator wall between second and third chambers. The walls are typically 12 inch wide cast in place concrete with #5 reinforcing bars at 12 inches on center vertically. The horizontal steel wass not shown on the drawings we have but may be #5 at 12 inch centers as well since that is used at other portions of the structure. The horizontal platforms and walkways are also 122 inches thick cast in place concrete and are reinforced with #5 reinforcing steel at 12 inches on center in each direction as well. Description of wall damage observed; The damage that we saw during our investigationn was extensive and complete. All chambers had the same level of corrosion at the same location on the structure. The damage was consistent along the flow level of the plants normal usage. 3

134 Fig. 5 View of separator wall between first and second chambers. The damage always appeared to be approximately three inchess into the structure. The reinforcing steel was not present in any of the walls we observed althoughh the level of damage extendedd into the wall deep enough that it would seem that the reinforcing steel would be present. The concrete is deteriorated enough that it could easy be chipped out and removed and a much deeper intrusionn would be needed to get to solid concrete. At locations in the structure where the water flow would come to a vertical element that protruded into the water flow the damage was even more severe. Figure s 4 and 5 show examples of walll / column vertical elements that have severe damage to them. At these locations the damage has removed enough concretee to simulate a large bite out of the wall system and no vertical or corner bar can be seen. Typical cover for reinforced cast in place walls is two inches, even if increased for waste water structures to three inches we feel that some exposed reinforcing bars should be seen. 4

135 Fig. 6 View of separator wall between second and third chambers. Figure s 6 and 7 show furtherr examples of damage too the walls which show how deep the damage is into the structure. All of the damage we have seen appears to be at a minimumm of two inches into the structure. Fig. 7 End of separator wall. 5

136 If the reinforcing steel is located at a 3 three inch cover, the corrosion levels we see here would indicate that those bars also severely corroded. Fig. 8 Shows an example of cracks in exterior walls around the structure. Fig. 9 Shows an example of wall cracks at lower portion off the wall along where construction joints may be located. 6

137 Walking around the structure there are also cracks onn all sides which could be cracks along the construction joints of the structure. The walls appear to have two horizontal cracks along them at about eight feet highh and aroundd 18 feet high. If these cracks are at construction joints, they joints do not follow the supplied plans since they show a single construction joint around 12 feet high. If the damage is at estimated three inch level and since the interior separator walls are 12 inches thick that would mean the interiorr walls have half of theirr original thickness removed or corroded. These walls would also have missing or damaged reinforcing steel bars on both sides of the walls. Structural wall analysis; The vertical loads on these walls are minimal and include their self-weight and the weight of the platforms and equipment that sits on them. They must also support the lateral loads of the water that is pushing on them, and sometimes support a deep wall beam thatt runs over an opening. For the vertical loads on a typical interiorr wall, it must support the walls self-weight and the equipment loads. From using the drawings in thee appendix we have estimated the equipment weight at 2,000 lbs. The weight will be distributed over 5 feet in width of wall on each side of an opening. So an interior wall will supportt two halves of the weight whichh would be 400 lb/ft total. The damage observed was approximately 1o feet below the top of the structure so at that location it will support 1o feet of wall at 150lb/ft. So a typical vertical load will support 1,500 lb/ft of wall self-weight and 400 lb/ft of equipment. If the wall was only 6 inches wide there that would be a pressuree of 26 psi whichh is well below the allowable for the concrete, soo the wall iss fine for these vertical loads. For the horizontal loads the structure willl have problems resisting the required lateral forces if it is only six inches wide and has no verticall reinforcement. We believe that the walls in their current condition cannot be relied on too support their code required forces. With no vertical bars and such a small cross section the walls are too badly damaged to work for the required wall bending moments if waterr was in one chamber and not the next chamber. We believe that the wall should have some structurall modifications to ensuree better performance or be replaced. These modifications at the least will be to remove the structure from service and have the walls thoroughly cleaned and removed from any corrosive chemicals and any old sealants. The walls will then need to have all of the loose material removed by chipping the old loose damaged concrete out until a solid concrete core is found. Any remaining reinforcing steel will need to be cleaned and have any rust removed. A new layer of steel reinforcing bars would have to be drilled or groove cut epoxied into the wall to replace the damaged and missing bars, the concrete 7

138 would have to be replaced with expansive hard strength epoxy cement that could fill all of the voids created by the damaged concrete. The repaired structure would then have to be relined with a new corrosion resistant liner that would preventt further damage at that point of the wall. After having some discussions with repair contractors we believee that a repair estimate to remove the damaged concrete, epoxy install the new reinforcing bars, and replace the missing concrete with epoxy cement would cost approximately $300,000. This number does not include any costs to bypass the structure, cleaning the walls, or any corrosive resistant liner. Conclusions and limitations; Based on the information we have about the structural propertiess of the walls, we believee that this structure should be replaced with a new structure. The repairs required to make the walls structural sound would be very costly and time extensive. The new reinforcing steel and epoxy concrete would have to support 50 % of all of the vertical loads and 100% of the water pressure lateral loads. The exterior walls also have cracks as well as several cracks in the walkway platforms. The structure is at leastt 27 years old and to expend the time and money to renovate the structure might not be worth it for that old of a structure. We have based our conclusions only on the data presented here in this report. I hope that this answers all of the questions concerning this retaining wall and we will be glad to meet and go over these comments and help you determine any possible repair and modifications that will be needed to insure a welll performing wall, or any additional studies needed to complete a detailed evaluation of the wall. Sincerely, Dennis Paul PE President 8

139 Appendix C Grit Removal System References

140 Grit Removal References Harris Co MUD 368 Roy Lackey, Year Installed: Hr Peak: 5.1 MGD No. of Units: 1 Quantity of Grit Removed: 2.5 CY/Week Type of Aeration: fine bubble Do you drain aeration basin to remove grit? Not yet although he expects there will eventually be some. Maintenance Issues: No Overall Satisfaction: Yes Satisfied with Smith and Loveless: Yes City of Rosenburg John Maresh, Year Installed: Hr Peak: gpm No. of Units: 1 Quantity of Grit Removed: CY/Week Type of Aeration: fine bubble Do you drain aeration basin to remove grit? No Maintenance Issues: There were problems right after installation that took a while to resolve; the system kept losing prime. It was finally fixed and they haven t had a problem since. They also recently had to replace mechanical seals. Overall Satisfaction: Yes Satisfied with Smith and Loveless: Yes

141 City of Pasadena Greg Jalowy, Year Installed: 2004 ADF and 2-Hr Peak: 5.7 to 7 MGD; MGD No. of Units: 2 Quantity of Grit Removed: 2-3 cy per week Type of Aeration: mechanical aerators Do you drain aeration basin to remove grit: yes due to return from racetrack; not much due to influent Maintenance Issues: no Overall Satisfaction: positive Satisfied with Smith and Loveless: positive City of Lake Jackson David Ellis, Year Installed: 2004 ADF and 2-Hr Peak: 3.2 MGD 19 MGD No. of Units: 1 Quantity of Grit Removed: 3.5 CY per week Type of Aeration: fine bubble Do you drain aeration basin to remove grit? Every 5 years Maintenance Issues: not really had to replace a seal Overall Satisfaction: positive Satisfied with Smith and Loveless: positive

142 Appendix D Required Air Flow Calculations

143 Appendix D Required Air Flow Calculations for Fine Bubble Diffusers 5.5 MGD Basins 2 and 3 Total Basin 1 Total Basins 4 and 5 Total Influent CBOD 5 (mg/l) - ADF 286 Influent CBOD 5 (mg/l) - ADF 286 Influent CBOD 5 (mg/l) - ADF 286 Influent NH 3 -N (mg/l) - ADF 30.5 Influent NH 3 -N (mg/l) - ADF 30.5 Influent NH 3 -N (mg/l) - ADF % of total flow 20% of total flow 33% of total flow Average Daily Flow (MGD) 2.58 Average Daily Flow (MGD) 1.10 Average Daily Flow (MGD) 1.84 Average Daily Influent BOD 5 (lbs/day) 6,148 Average Daily Influent BOD 5 (lbs/day) 2,624 Average Daily Influent BOD 5 (lbs/day) 4,387 Actual Oxygen Requirement (lbs O 2 /lbs BOD 5 ) ( ) Actual Oxygen Requirement (lbs O 2 /lbs BOD 5 ) 1.66 Actual Oxygen Requirement (lbs O 2 /lbs BOD 5 ) 1.66 Average (lb O 2 /day) 10,201 Average (lb O 2 /day) 4,353 Average (lb O 2 /day) 7,279 Fine Bubble Aeration Fine Bubble Aeration Fine Bubble Aeration Airflow Rate Correction Factor 0.99 See Table F5 in TAC Airflow Rate Correction Factor 1.65 Airflow Rate Correction Factor 0.91 Diffuser depth, ft 12.5 Diffuser depth, ft 9.3 Diffuser depth, ft 15 CWOTE 0.26 mfg provided CWOTE 0.26 CWOTE 0.26 Fine bubble diffuser multiplication factor 0.45 See (b) (2) (B) (i) Fine bubble diffuser multiplication factor 0.45 Fine bubble diffuser multiplication factor 0.45 WOTE WOTE WOTE Required Air Flow (RAF) (SCFM) 3,457 ( ) ( ) Required Air Flow (RAF) (SCFM) 2,473 Required Air Flow (RAF) (SCFM) 2,279 = Check mixing requirements (SCFM per SF) 0.18 * Check (SCFM per SF) 0.22 Check (SCFM per SF) 0.20 *TCEQ requires greater than or equal to 0.12scfm/sf for fine bubble diffusers Basins 2 and 3 266,490 CF Basin 1 111,966 CF Basins 4 and 5 190,163 CF Basins 2 and 3 19,740 SF Basin 1 11, SF Basins 4 and 5 11,645 SF Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

144 Appendix D Required Air Flow Calculations for Fine Bubble Diffusers 9.25 MGD Basins 2 and 3 Total Basin 1 Total Basins 4 and 5 Total Influent CBOD 5 (mg/l) - ADF 286 Influent CBOD 5 (mg/l) - ADF 286 Influent CBOD 5 (mg/l) - ADF 286 Influent NH 3 -N (mg/l) - ADF 30.5 Influent NH 3 -N (mg/l) - ADF 30.5 Influent NH 3 -N (mg/l) - ADF % of total flow 20% of total flow 33% of total flow Average Daily Flow (MGD) 4.34 Average Daily Flow (MGD) 1.82 Average Daily Flow (MGD) 3.09 Average Daily Influent BOD 5 (lbs/day) 10,340 Average Daily Influent BOD 5 (lbs/day) 4,345 Average Daily Influent BOD 5 (lbs/day) 7,379 Actual Oxygen Requirement (lbs O 2 /lbs BOD 5 ) ( ) Actual Oxygen Requirement (lbs O 2 /lbs BOD 5 ) 1.66 Actual Oxygen Requirement (lbs O 2 /lbs BOD 5 ) 1.66 Average (lb O 2 /day) 17,156 Average (lb O 2 /day) 7,208 Average (lb O 2 /day) 12,242 Fine Bubble Aeration Fine Bubble Aeration Fine Bubble Aeration Airflow Rate Correction Factor 0.99 See Table F5 in TAC Airflow Rate Correction Factor 1.65 Airflow Rate Correction Factor 0.91 Diffuser depth, ft 12.5 Diffuser depth, ft 9.3 Diffuser depth, ft 15 CWOTE 0.26 mfg provided CWOTE 0.26 CWOTE 0.26 Fine bubble diffuser multiplication factor 0.45 See (b) (2) (B) (i) Fine bubble diffuser multiplication factor 0.45 Fine bubble diffuser multiplication factor 0.45 WOTE WOTE WOTE Required Air Flow (RAF) (SCFM) 5,815 ( ) ( Required Air Flow (RAF) (SCFM) 4,095 Required Air Flow (RAF) (SCFM) 3,833 ) = Check mixing requirements (SCFM per SF) 0.29 * Check (SCFM per SF) 0.36 Check (SCFM per SF) 0.33 *TCEQ requires greater than or equal to 0.12scfm/sf for fine bubble diffusers Basins 2 and 3 266,490 CF Basin 1 111,966 CF Basins 4 and 5 190,163 CF Basins 2 and 3 19,740 SF Basin 1 11, SF Basins 4 and 5 11,645 SF Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

145 Appendix D Required Air Flow Calculations for Coarse Bubble Aeration 5.5 MGD Basins 2 and 3 Total Basin 1 Total Basins 4 and 5 Total Influent CBOD 5 (mg/l) - ADF 286 Influent CBOD 5 (mg/l) - ADF 286 Influent CBOD 5 (mg/l) - ADF 286 Influent NH 3 -N (mg/l) - ADF 30.5 Influent NH 3 -N (mg/l) - ADF 30.5 Influent NH 3 -N (mg/l) - ADF % of total flow 26% of total flow 31% of total flow Average Daily Flow (MGD) 2.37 Average Daily Flow (MGD) 1.10 Average Daily Flow (MGD) 1.69 Average Daily Influent BOD 5 (lbs/day) 5,642 Average Daily Influent BOD 5 (lbs/day) 2,624 Average Daily Influent BOD 5 (lbs/day) 4,026 Actual Oxygen Requirement (lbs O 2 /lbs BOD 5 ) ( ) Actual Oxygen Requirement (lbs O 2 /lbs BOD 5 ) 1.66 Actual Oxygen Requirement (lbs O 2 /lbs BOD 5 ) 1.66 Average (lb O 2 /day) 9,360 Average (lb O 2 /day) 4,353 Average (lb O 2 /day) 6,679 Coarse Bubble Aeration Coarse Bubble Aeration Coarse Bubble Aeration Airflow Rate Correction Factor 0.99 Airflow Rate Correction Factor Airflow Rate Correction Factor 0.91 Diffuser Depth, ft Diffuser Depth, ft Diffuser Depth, ft CWOTE 0.09 CWOTE 0.10 CWOTE 0.11 Coarse bubble diffuser multiplication factor 0.65 Coarse bubble diffuser multiplication factor 0.65 Coarse bubble diffuser multiplication factor 0.65 WOTE 0.06 ( ) ( ) WOTE 0.07 WOTE 0.07 = Required Air Flow (RAF) (SCFM) 6,091 Required Air Flow (RAF) (SCFM) 2,998 Required Air Flow (RAF) (SCFM) 3,281 Check mixing requirements (SCFM per SF) 309 * Check mixing requirements (SCFM per SF) 265 * Check mixing requirements (SCFM per SF) 282 *TCEQ requires greater than or equal to 20 scfm/1000 cf for coarse bubble diffusers Basins 2 and 3 266,490 CF Basin 1 163,037 CF Basins 4 and 5 190,163 CF Basins 2 and 3 19,740 SF Basin 1 11, SF Basins 4 and 5 11,645 SF Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

146 Appendix D Required Air Flow Calculations for Coarse Bubble Aeration 9.25 MGD Basins 2 and 3 Total Basin 1 Total Basins 4 and 5 Total Influent CBOD 5 (mg/l) - ADF 286 Influent CBOD 5 (mg/l) - ADF 286 Influent CBOD 5 (mg/l) - ADF 286 Influent NH 3 -N (mg/l) - ADF 30.5 Influent NH 3 -N (mg/l) - ADF 30.5 Influent NH 3 -N (mg/l) - ADF % of total flow 26% of total flow 31% of total flow Average Daily Flow (MGD) 3.98 Average Daily Flow (MGD) 2.43 Average Daily Flow (MGD) 2.84 Average Daily Influent BOD 5 (lbs/day) 9,488 Average Daily Influent BOD 5 (lbs/day) 5,805 Average Daily Influent BOD 5 (lbs/day) 6,771 Actual Oxygen Requirement (lbs O 2 /lbs BOD 5 ) ( ) Actual Oxygen Requirement (lbs O 2 /lbs BOD 5 ) 1.66 Actual Oxygen Requirement (lbs O 2 /lbs BOD 5 ) 1.66 Average (lb O 2 /day) 15,742 Average (lb O 2 /day) 9,631 Average (lb O 2 /day) 11,234 Coarse Bubble Aeration Coarse Bubble Aeration Coarse Bubble Aeration Airflow Rate Correction Factor 0.99 Airflow Rate Correction Factor Airflow Rate Correction Factor 0.91 Diffuser Depth, ft Diffuser Depth, ft Diffuser Depth, ft ( ) ( ) CWOTE 0.09 = CWOTE 0.10 CWOTE 0.11 Coarse bubble diffuser multiplication factor Coarse bubble diffuser multiplication factor 0.65 Coarse bubble diffuser multiplication factor 0.65 WOTE 0.06 WOTE 0.07 WOTE 0.07 Required Air Flow (RAF) (SCFM) 10,244 Required Air Flow (RAF) (SCFM) 5,521 Required Air Flow (RAF) (SCFM) 5,517 Check mixing requirements (SCFM per SF) 519 * Check mixing requirements (SCFM per SF) 488 * Check mixing requirements (SCFM per SF) 474 *TCEQ requires greater than or equal to 20 scfm/1000 cf for coarse bubble diffusers Basins 2 and 3 266,490 CF Basin 1 163,037 CF Basins 4 and 5 190,163 CF Basins 2 and 3 19,740 SF Basin 1 11, SF Basins 4 and 5 11,645 SF Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

147 Appendix E Existing Aeration Blowers Curves

148 AD SO# PSIA SN , PSIG Disch. 100F

149 AD SO# PSIA SN , , PSIG disch. 100F

150 Appendix F Air Headloss Calculations

151 Appendix F Air Headloss Calculations Aeration Basin 1 A. AIR DEMAND CALCULATIONS EQUIPMENT Reference: WEF Manual of Practice No.8, 1991 P. 444 ACFM 4569 cu.ft./min Standard Temperature T s 68 F Standard Temperature T s 528 R Standard Relative Humidity RH s 0.36 Actual Relative Humidity RHa 1.00 Standard pressure P s PSIA Saturated vapor pressure of water at standard temperature PV s PSIA Saturated vapor pressure of water at actual temperature PVa PSIA Correction factor for actual conditions Ta/Ts Actual Pressure Pa PSIA Pb/Pa SCFM 4095 cu.ft./min B. AIR HEAD LOSS CALCULATIONS Reference: Wastewater Engineering by Metcalf & Eddy, Inc., 1991, P. 568 Length of the pipe 200 ft Pipe diameter 16 in Actual air temperature T a 100 F Actual air temperature T a 560 R Elevation 20 ft Barometer Pressure Pb PSIA Blower efficiency assumed 0.8 Blower discharge pressure 5.03 PSIG Temperature rise 55 Air temperature at blower discharge 155 Assumed average air temperature in pipe 160 Viscosity of air 0.02 Reynolds Number 394,053 "e" Value e/d f f+ 10% Air flow rate in the pipe 3696 cu.ft./min Area of the pipe 1.40 Sq.Ft. Velocity in the pipe 2,647 Ft/min 44 Ft/sec Weight of discharge pressure lb/cu.ft. Velocity Head of air in water In of water Air headloss 2.23 In of water Depth of water over diffusers 9.25 ft Head loss through the fittings: a. Check Valve K= In of water b. Elbows (6) K= In of water c. Butterfly valves (2) K= In of water Inlet pressure drop (Manufacturer's data) 0.2 psi Discharge pressure drop (Manufacturer's data) 0.1 psi Head loss over the air diffuser 6 In of water Allowance for clogging 6 In of water Total head loss 5.03 psi Maximum air pressure at the header at the fitting of the diffusion unit, 4.44 psi Provide blower with air flow of: 4100 SCFM 5.1 PSIG Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

152 Appendix F Air Headloss Calculations Aeration Basins 2 and 3 A. AIR DEMAND CALCULATIONS EQUIPMENT Reference: WEF Manual of Practice No.8, 1991 P. 444 ACFM 6488 cu.ft./min Standard Temperature T s 68 F Standard Temperature T s 528 R Standard Relative Humidity RH s 0.36 Actual Relative Humidity RHa 1.00 Standard pressure P s PSIA Saturated vapor pressure of water at standard temperature PV s PSIA Saturated vapor pressure of water at actual temperature PVa PSIA Correction factor for actual conditons Ta/Ts Actual Pressure Pa PSIA Pb/Pa SCFM 5815 cu.ft./min B. AIR HEAD LOSS CALCULATIONS Reference: Wastewater Engineering by Metcalf & Eddy, Inc., 1991, P. 568 Length of the pipe 390 ft Pipe diameter 18 in Actual air temperature T a 100 F Actual air temperature T a 560 R Elevation 20 ft Barometer Pressure Pb PSIA Blower efficiency assumed 0.8 Blower discharge pressure 6.58 PSIG Temperature rise 71 Air temperature at blower discharge 171 Assumed average air temperature in pipe 160 Viscosity of air 0.02 Reynolds Number 497,376 "e" Value e/d f f+ 10% Air flow rate in the pipe 4988 cu.ft./min Area of the pipe 1.77 Sq.Ft. Velocity in the pipe 2,822 Ft/min 47 Ft/sec Weight of discharge pressure lb/cu.ft. Velocity Head of air in water In of water Air headloss 4.74 In of water Depth of water over diffusers 12.5 ft Head loss through the fittings: a. Check Valve K= In of water b. Elbows (6) K= In of water c. Butterfly valves (2) K= In of water Inlet pressure drop (Manufacturer's data) 0.2 psi Discharge pressure drop (Manufacturer's data) 0.1 psi Head loss over the air diffuser 6 In of water Allowance for clogging 6 In of water Total head loss 6.58 psi Maximum air pressure at the header at the fitting of the diffusion unit, 5.84 psi Provide blower with air flow of: 5820 SCFM 6.6 PSIG Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

153 A. AIR DEMAND CALCULATIONS EQUIPMENT Reference: WEF Manual of Practice No.8, 1991 P. 444 Appendix F Air Headloss Calculations Aeration Basins 4 and 5 ACFM 4277 cu.ft./min Standard Temperature T s 68 F Standard Temperature T s 528 R Standard Relative Humidity RH s 0.36 Actual Relative Humidity RHa 1.00 Standard pressure P s PSIA Saturated vapor pressure of water at standard temperature PV s PSIA Saturated vapor pressure of water at actual temperature PVa PSIA Correction factor for actual conditions Ta/Ts Actual Pressure Pa PSIA Pb/Pa SCFM 3833 cu.ft./min B. AIR HEAD LOSS CALCULATIONS Reference: Wastewater Engineering by Metcalf & Eddy, Inc., 1991, P. 568 Length of the pipe 527 ft Pipe diameter 18 in Actual air temperature T a 100 F Actual air temperature T a 560 R Elevation 20 ft Barometer Pressure Pb PSIA Blower efficiency assumed 0.8 Blower discharge pressure 7.57 PSIG Temperature rise 82 Air temperature at blower discharge 182 Assumed average air temperature in pipe 160 Viscosity of air 0.02 Reynolds Number 327,895 "e" Value e/d f f+ 10% Air flow rate in the pipe 3189 cu.ft./min Area of the pipe 1.77 Sq.Ft. Velocity in the pipe 1,805 Ft/min 30 Ft/sec Weight of discharge pressure lb/cu.ft. Velocity Head of air in water In of water Air headloss 2.74 In of water Depth of water over diffusers 15.3 ft Head loss through the fittings: a. Check Valve K= In of water b. Elbows (6) K= In of water c. Butterfly valves (2) K= In of water Inlet pressure drop (Manufacturer's data) 0.2 psi Discharge pressure drop (Manufacturer's data) 0.1 psi Head loss over the air diffuser 6 In of water Allowance for clogging 6 In of water Total head loss 7.57 psi Maximum air pressure at the header at the fitting of the diffusion unit, 7.06 psi Provide blower with air flow of: 3840 SCFM 7.1 PSIG Klotz Associates Project No March 2012 Gulf Coast Waste Disposal Authority Blackhawk WWTP Rehabilitation

154 Appendix G Jestec Field Services, Inc. Field Report

155 Jestec Services, Inc. Field Visit Report By: Jack Jessop CC: Tonya Washington To: Kevin Smith Customer Name: Gulf Coast Waste Disposal Authority Contract #: Date of Visit: October 20, 2009 Location: 3902 West Bay area Boulevard Friendswood, Texas Phone: or Directions: I-45S toward Galveston to the Bay Area Boulevard Exit go west to Hwy sign on right (Blackhawk WWTP) Equipment: (2) ABW Filters 16 X 86, 8 Cells, 16 Dual Media Purpose of Visit: ABW Filter Inspection, Evaluation & Recommendations for rehabilitation. Personnel Contacted: Clyde LeBlanc Ops. Supervisor Gulf Coast Waste Disposal Joseph Terrance, E.I.T Engineer Dannenbaum Engineering Dennis Fishbeck IDI Rep. Hartwell Environmental, Corp. October 20, 2009 Tuesday: Dennis Fishbeck and I arrived at the plant and met with the above listed people to discuss the status of the ABW Filters. Clyde LeBlanc explained that the filters are approximately 15 years old and are experiencing issues regarding the underdrain system and carriage backwashing components. We moved the discussion to the filter area and conducted a detailed inspection of the filters. Clyde had drained filter # 1 in preparation for our inspection and advised that both filter underdrains are in similar condition. Page 1 of 3

156 We spent time inspecting and discussing the filter tanks, backwash components and noted the following conditions: 1. Underdrain System practically all of the fiberglass cell dividers are damaged and broken. Many of the porous plates in the individual cells are dislodged or broken with broken retaining angles. 2. Media The filter sand and anthracite media is missing or low in level in the individual cells. The missing media has either leaked into the underdrain system or has inadvertently been pumped out during backwash. 3. Carriage Rails The stainless steel rail caps are missing and the rails are rusty and corroded. 4. Backwash Carriages The galvanized carriage frames are painted and the paint has deteriorated and is pealing off in large pieces. 5. Carriage Wheels The drive and idler wheels (flanges & tread surface) are worn causing traction issues. 6. Carriage Gearbox - Rusty and corroded but operable. 7. Carriage Handrail worn but functional. 8. Backwash Arm and Tensioning Springs Rusted & corroded 9. Backwash Shoe functional 10. Washwater Hood The fiber glass hood is in good condition. 11. Washwater Discharge Launder Trough The trough is the old style half pipe design and is damaged and weak. 12. Electrical Control Panels The control panels were replaced approximately 6 years ago and are in good condition. 13. Electrical Festoon System The festoon power cables are damaged and spliced and the cable trolleys are broken. 14. Backwash & Washwater Pumps Both pumps have been upgraded to the current design submersible and are performing well. 15. Skimmer Pump The Skimmer pump in not the current design and is severely corroded. After the above listed inspection, we returned to the plant office and discussed the observations and recommended corrective action as follows: Filter Media Replace Underdrain System the underdrain system is in bad condition and should be upgraded to the newest Quickplate design. Backwash Carriage Components - The following components are in need of replacement: a. Carriage Wheels, bearings, shafts, etc. b. Backwash Arm & Tensioning Springs. c. Backwash & Washwater Pump throttle valves and piping. d. Skimmer Pump Replace skimmer pump and mounting bracket. Washwater Launder Troughs Replace trough & mounting brackets Page 2 of 3

157 Festoon System Replace cable and trolleys. Backwash Carriage Frame Sand blast and repaint with epoxy paint system. Carriage Rails Sand blast and paint install new stainless steel rail caps. After our discussion, Joseph Terrance requested that IDI provide a quotation for the Quickplate underdrain system and the listed carriage and tank components listed above. Since the field labor to repaint and replace the carriage components will be a cost factor, Joseph Terrance requested a separate quotation for new factory assembled carriages for comparison. Note: The quoted carriages should include all new components except control panels, deck plates and washwater hood. This ended our visit. Before departing, Joseph Terrance advised that he would like to have the quotation by the end of October, 2009 for budgeting purposes. Page 3 of 3

158 Appendix H Delta Structural Technology Proposal

159 Delta Structural Technology, LLC 3601 N Loop 336 West Conroe, Texas (281) Office (936) Cell January 4, 2012 Paul Engineering, Inc. 626 ½ Barringer Lane, Suite A Webster, TX Attn: Dennis Paul P.E. Re: Blackhawk WWP, Friendswood, TX Thank you for allowing Delta Structural Technology, LLC the opportunity to submit our proposal for the Blackhawk WWP project. The purpose of this repair is to re-establish the capacity of the spalling, delaminating and eroded concrete from corrosion distress. Installation of rebar, surface mounted FRP and top coating to provide confinement and reinforcement for flexure and shear. We have prepared our construction schedule and estimate based on the information received by Dennis Paul and site visit. Due to the technical nature of this type of repair we are using our technical construction team that specializes in this type of work. All of the products required have a very specific temperature and working time. Construction Schedule: Mobilize Secure the construction area, staging Removal of spall and delaminating concrete Replace required rebar Build Forms Crack injection, larger than Repair existing concrete with high strength epoxy repair mortar Install flexural surface mounted FRP Clean area for final inspection We will, gladly, join you and others to discuss and explain the scope of work we are proposing based on the engineers design and recommendations. Pricing for Repair: $192, Concrete Repair, 28 days: $192,484.00

160 Concrete, high strength repair: Sika High Strength Repair Mortar, flow-able Sika High Strength Repair Mortar, hand patch Forming material Labor: 6 man crew, 8 hour day 30 working days estimated Assemble scaffolding. Demo failing or damaged concrete, inspect corroded steel, wire brush clean or replace, hand patch concrete or form and pour prior to epoxy and FRP application. Crack injection when required. Equipment, Supplies, Materials: Abrasive diamond grinding disks, disposable gloves, suits for concrete & epoxy work, drill bits, bondo knives, roller covers & handles, mixing buckets, plastic sheeting, duct tape, industrial scissors, epoxy, fiber re-enforced polymer, Acetone, wire brush cups and hand held, concrete mixer, drills, generators, grinders, hammer drills, scaffolding, trucks, enclosed trailers, onsite office equipment. Exclusions: Cost for bonding or sales tax if required FRP Testing Onsite Inspections by engineer Thank you, Curtis Ardoin Vice President Business Development Delta Structural Technology