Tiffin Water Treatment Plant. Comprehensive Facility Plan (Audit)

Transcription

1 2014 HDR Architecture, HDR, HDR, Inc., all all rights reserved.

2 Tiffin Water Treatment Plant Comprehensive Facility Plan (Audit) May 2016 Jim Welty Aqua Ohio Jill Marie P.E. Rich Atoulikian P.E. Glenn Dostal P.E. HDR 2014 HDR, all rights reserved.

3 Agenda What is an Audit? Why are Audits Conducted? How are Audits Conducted? Application at the Tiffin WTP: o Facility Overview o Findings and Recommendations o Capital Planning o Key Considerations

4 What is an Audit? Comprehensive Review of the WTP: o Facility Inventory and Data Collection o Condition Assessment: Performance Condition Reliability and Redundancy o Develop Project Descriptions and Cost Estimates o Prioritize Projects o Develop Capital Improvements Program Conducted on a rotating 4 5 year basis

5 What is an Audit? Key Considerations: o Performance: Water Quality Current and Future Water Demands Current and Future Regulations Approved Capacity Analysis o Condition Assessment o Reliability and Redundancy Reliability Redundancy Condition Assessment Water Quality Comprehensive Facility Plan Approved Capacity Analysis Future Regulations Current Water Demands Future Water Demands Current Regulations

6 Why are Audits Conducted? Capturing Key Knowledge Develop Capital Improvements Plan Operation Optimization Training New Employees Succession Planning

7 How are Audits Conducted? Interview Plant Personnel o Management o Plant Operations Staff Review Historic Plant Data Visual Inspection of Plant Additional Quantitative Analysis, as needed

8 How are Audits Conducted? Five Levels of Inspection Level 5 Destructive Forensic Testing Level 4 Non-destructive Forensic Testing Level 3 Performance Testing Tiffin Level 2 Observation Level 1 Age

9 How are Audits Conducted? Single Team Approach Process Structural Mechanical Electrical I&C and SCADA

10 How are Audits Conducted? ASMEC Form Example

11 How are Audits Conducted? Process Form Example

12 How are Audits Conducted? Aqua Standard Electrical and I&C Forms

13 How are Audits Conducted? Condition Assessment Ratings

14 How are Audits Conducted? Reliability Risk Assessment Ratings

15 How are Audits Conducted? Performance Assessment Ratings

16 Condition Assessment Decision Tree

17 Condition Assessment Framework A well-defined asset inventory will facilitate project prioritization

18 Example Tiffin WTP

19 Facility Overview General Combined Surface and Groundwater Sources o Sandusky River o 4 wells Average Daily Production Rate = 1.8 MGD Sole source of water for City of Tiffin (no interconnections)

20 Facility Overview - Treatment Process Conventional Treatment: o Coagulation o Flocculation o Sedimentation o Multi-media filtration including GAC o Disinfection o Fluoridation o Finished Water Storage (with aeration system) Sodium Hypochlorite Primary and Secondary Disinfection Applied Pre-Settling, Post-Settling (Intermediate), and Post-Filtration Poly-Aluminum Chloride (PACL) Coagulant Aid (Polymer) Powdered Activated Carbon (PAC) Coagulation To facilitate floc formation and algae removal in the Settling Basins during warmer months Taste and Odor Control Hydrofluosilicic Acid (Fluoride) For dental care, as required by Ohio Code

21 Facility Overview Settling Basin #1 Raw and Finished Water Pumps Sludge/Drain Pump Station Backwash Transfer Tank Filters 1-3 Mixing Tank Settling Basin #2 Filtered Water Transfer Pumps Wash Water Storage Tank Surface Water Intake Well Mill Race

22 Facility Overview Lagoon #2 Finished Water Clearwell Dried Sludge stockpile Lagoon #1 Head Gate & Screen Intake Structure

23 Historical Water Demands

24 Water Quality Challenges Surface Water: o Turbidity 10 NTU to 2,500 NTU Up to 7,000 NTU on occasion o Algae Issues o High Nitrate Levels Groundwater: o High Strontium Levels Typical blend ratio: o 65% (surface) to 35% (groundwater) o Temperature adjustment

25 Key Existing SDWA Regulations Surface Water Treatment Rule (SWTR) Lead and Copper Rule and Revisions Total Coliform Rule (TCR) Interim Enhanced Surface Water Treatment Rule (IESWTR) Stage 1 Disinfection Byproducts Rule (Stage 1 DBPR) Filter Backwash Recycling Rule Radionuclide Rule Arsenic Rule Stage 2 Disinfection Byproducts Rule (Stage 2 DBPR) Long-Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR)

26 Raw Water Turbidity

27 Settled and Filtered Water Turbidity

28 TTHM - LRAA

29 HAA - LRAA

30 Key Future Regulations Strontium Perchlorate Long-Term Lead and Copper Rule (LT-LCR) Revisions Carcinogenic VOCs (cvocs) Hexavalent Chromium Nitrosamines Chlorate

31 Flocculation (Mixing Tank) - Capacity Component Number of Units Description Design Criteria Required / Recommended Component Capacity (MGD) Flow Basis of Component (Capacity/Ratio) Equivalent Max-Day Capacity (MGD) Flocculation (Mixing Tank) 1 28' dia. X 14' swd Volume = MG Detention time 30 minutes Recommended 3.10 MGD - - Center feed radial flow tank

32 Sedimentation - Capacity Component Number of Units Description Design Criteria Required / Recommended Component Capacity (MGD) Flow Basis of Component (Capacity/Ratio) Equivalent Max-Day Capacity (MGD) Sedimentation 2 Settling Basin #1: L = 79.50', W = SWD = 11.50') Volume = MG Settling Basin #2: Dia = 75 SWD = 11' Volume = MG HDT 4 hours Required 1.83 MGD max day 1.0 WOR 20,000 gpd/ft Required Not Applicable Surface Loading Rate 0.5 gpm/ft MGD Recommended 2.56 MGD - - HDT 4 hours Required 2.18 MGD max day 1.0 WOR 20,000 gpd/ft Required Not Applicable Surface Loading Rate 0.5 gpm/ft MGD Recommended 3.18 MGD - - Sedimentation Total: 4.01 MGD Settling Basin #1 End feed rectangular basin with submerged discharge orifice cones at opposite end. Settling Basin #2 Peripheral feed spiral flow basin with discharge point located at the center of the tank.

33 Filters - Capacity Component Number of Units Description Design Criteria Required / Recommended Component Capacity (MGD) Flow Basis of Component (Capacity/Ratio) Equivalent Max-Day Capacity (MGD) Filters 3 Filters #1 and #2: 22' x 12' each Area = 264 ft 2 each Filter #3: 21'-10" x 12'-2" Area = 266 ft 2 Total Filter Area = 794 ft 2 Max-Day (with largest unit out-of-service); Filtration Rate less than or equal to 4 gpm/ft 2 Required 3.04 MGD max day MGD 160 hours run time between backwashes. Less than 24 hours without pre-chlorination. Free chlorine residual in the settling basins and to the filter tops are kept as low as possible to address algae issue, but minimize formation of DBPs.

34 Clearwell - Capacity Component Number of Units Description Design Criteria Required / Recommended Component Capacity (MGD) Flow Basis of Component (Capacity/Ratio) Equivalent Max-Day Capacity (MGD) Cleawell 1 (with 2 cells) Cell #1: ' swd Cell #2: ' swd Total: ' swd Max CT req'd for 0.5-log Giardia inactivation = 41 mg/l x min Required MGD peak hour treatment MGD Assumptions: Max CT value = 41 mg/l-min: min Cl 2 = 1.64 mg/l, max ph > 8 min temperature = 5 deg-c

35 Recommendations Source Water: Major Component Recommendation Priority Groundwater Wells Retain services of a Hydrogeologist to study well production rate trends to understand the reliability of the capacity of the existing wells. Install additional production well. 1 Conduct SWIP and MPA testing to determine whether or not the well sources are actually under the influence of surface water. 1 1 Based upon the results of the SWIP and MPA testing, consider a contingency plan which involves placing infrastructure to allow supply of well water directly to either the Filters or the Clearwell for additional reliability. 2

36 Recommendations Mixing Tank: Major Component Mixing Tank Recommendation Repair all moderate to severe deterioration along the concrete foundation at the base of the tank and minor tank corrosion. Consider replacing existing tank and adding a second tank. Priority 1 1-2

37 Recommendations Settling Basins: Major Component Recommendation Priority Replace wooden baffles with FRP. 2 Settling Basin #1 Settling Basin #2 Complete all necessary repair work recommended in May 2011 Tank Inspection Report. Replace WEDA sludge removal system. Complete all necessary repair work recommended in May 2011 Tank Inspection Report. Install a baffle with scum removal trough to facilitate removal of floating material. Replace WEDA sludge removal system

38 Recommendations Filters and Filtered Water Transfer Pumps: Major Component Filtered Water Transfer Pumps Recommendation Install a third pump to increase redundancy capacity and improve reliability. Replace two existing pumps prior to reaching the end of their useful life. Priority 1 2

39 Recommendations Clearwell and Finished Water: Major Component Recommendation Priority Finished Water Clearwell Aeration System High Service Pumping Monitor and Repair minor damage caused by wildlife to the protective structural panel façade of the clearwell tank. Continue Operation - Change out Pump #13 to a vertical arrangement similar to Pumps #15, #16, and #17. Equip Pumps #13 and #16 with a VFD

40 Other Process Recommendations Process Concern Strontium Removal Algae Speciation Algae control and DBP reduction Recommendation Possible Cation Exchange System. Perform treatment technology analysis to confirm the best treatment option for strontium. Purchase testing equipment and complete algae speciation to determine the impact that potential algae toxin regulations may have at this facility (complete each season). Conduct additional studies to evaluate the alternatives of chlorine dioxide or dissolved air flotation for algae control. Chlorine dioxide as a pre-oxidant would also help reduce DBP formation. Priority 2 1 1

41 Recommendations Structural: o Repair and seal cracks, repair spalled concrete, address areas with minor corrosion. o Analyze buckled bracing at retaining walls along the Mill Race Channel. o Flood Panel - Flood Log - stop gate system for all at risk doors.

42 Recommendations Electrical: o Single point failures that could result in prolonged interruption of the WTP operation. (Active and standby pumps connected to same MCC) o Critical facilities have back-up power supply. (Aeration System and Wells) Mechanical (HVAC): o Proper ventilation in accordance with code requirements.

43 Capital Planning

44 Key Considerations Plan your attack Take experienced team o Code issues are a big factor Meet with plant staff to obtain history, records, and reports Team up with applicable owner discipline during site visit Take pictures, take more pictures Summarize results and complete estimate ASAP Plan for the future Develop initial project priorities, then review, adjust and finalize with Owner

45 Questions