MacDonnell Heights Town Center. Poughkeepsie Corporate Center Wastewater Treatment Plant. DRAFT Existing Conditions Report. MHTC Development, LLC

Transcription

1 MacDonnell Heights Town Center Town of Poughkeepsie, Dutchess County, New York Poughkeepsie Corporate Center Wastewater Treatment Plant DRAFT Existing Conditions Report Prepared for: MHTC Development, LLC 199 West Road, Suite 101 Pleasant Valley, NY Prepared by: Delaware Engineering, D.P.C. 28 Madison Avenue Extension Albany, New York February 2017

2 MacDonnell Heights Town Center DRAFT Existing Conditions Report - PCC WWTP TABLE OF CONTENTS Section Page 1.0 INTRODUCTION Facility Overview and History Flood Zone Regulatory and Design Standards EXISTING WWTP HYDRAULIC AND ORGANIC LOADING Existing Loading and SPDES Permit EXISTING WASTEWATER SYSTEM EVALUATION Evaluation Approach Main Influent Pump Station and Preliminary Treatment Biological Treatment Process Secondary Clarification Return Activated Sludge Effluent Filtration Disinfection Sludge Holding Unit Process Capacity Summary 7 TABLES Table 2.1 Historical Influent Loading 2 Table 2.2 SPDES Permit Limits WWTP Discharge 2 Table 3.1 Existing Facility Capacity Summary 7 FIGURES Figure 1 Figure 2 Location Map Flood Zone Map APPENDICES Appendix A Poughkeepsie Corporate Center WWTP SPDES Permit # NY Delaware Engineering, D.P.C. i

3 MacDonnell Heights Town Center DRAFT Existing Conditions Report - PCC WWTP 1.0 INTRODUCTION 1.1 Facility Overview and History The Poughkeepsie Corporate Center Wastewater Treatment Plant (PCC WWTP) is located in the Town of Poughkeepsie at 900 Dutchess Turnpike (U.S. Route 44). A Location Map is included as Figure 1. The PCC WWTP was constructed in the 1960s with a permitted capacity of 20,000 gallons per day (gpd) and provides sewer service to the Poughkeepsie Business Park. The facility discharges to the Wappingers Creek and is regulated via State Pollutant Discharge Elimination System (SPDES) Permit # NY Currently, the flow to the facility is significantly less than the permitted capacity of the system. While permitted for 20,000 gpd, the facility treats approximately 2,900 gpd. As a result of the low flows to the system only a portion of the facility is utilized. The purpose of this report is to determine the actual capacity and evaluate the existing conditions at the PCC Wastewater Treatment Plant. 1.2 Flood Zone The PCC WWTP site is located within the 100 Year Flood Zone AE according to FEMA Flood Insurance Rate Map (FIRM) Number 36027C0378E for the Towns of La Grange and Poughkeepsie, effective May 2, The Base Flood Elevation at the WWTP is approximately 167 referenced to the North American Vertical Datum 1988 (NAVD88). Figure 2 shows the FEMA Digital FIRM layers including the Floodway, Flood Zones and Base Flood Elevations, 2 foot contours created from NYS 1 meter DEMs, and 2013 NYS orthoimagery of the site area. The PCC wastewater facilities where designed and constructed to accommodate the 100 year flood. The finished floor elevation is approximately 175 at the wastewater treatment plant and approximately 171 at the pump station. 1.3 Regulatory and Design Standards This Engineering Report is prepared in conformance with the following standards: Recommended Standards for Wastewater Facilities, Great Lakes-Upper Mississippi River Board of State Public Health & Environmental Managers, 2014, (commonly referred to as Ten States Standards) TR-16 Guides for the Design of Wastewater Treatment Work, New England Interstate Water Pollution Control Commission, 2016, (referred to as TR16) New York State Design Standards for Intermediate Sized Wastewater Treatment Systems, NYS Department of Environmental Conservation, 2014, (referred to as NYS2014) Wastewater Engineering Treatment and Resource Recovery, 5 th Edition, Metcalf & Eddy / EACOM, 2014, (referred to as Metcalf & Eddy) Delaware Engineering, D.P.C. 1

4 MacDonnell Heights Town Center DRAFT Existing Conditions Report - PCC WWTP 2.0 EXISTING WWTP HYDRAULIC AND ORGANIC LOADING 2.1 Existing Loading and SPDES Permit SPDES Permit # NY provides discharge limits for three distinct outfalls. The WWTP is regulated via Outfall #001. Outfalls #002 and #003 are related to cooling water, softener backwash, etc. from specific processes within other facilities in the business park. These outfalls are unrelated to the functioning of the WWTP and this report focuses solely on Outfall #001. Table 2.1 lists the influent loading characteristics for the PCC WWTP which were used in the evaluation of the existing facility. These loading characteristic are based on a combination of the influent testing results along with typical medium strength wastewater in accordance with Table 3-18 of Metcalf & Eddy and are as follows: Table 2.1 Historical Influent Loading Parameter Historical Influent Concentration Current Annual Average Daily Flow (ADF) 2,900 gpd ( ) BOD mg/l (2014 data) TSS 380 mg/l (2014 data) NH3 (as N) 20 mg/l M&E Medium Strength TN (as N) 35 mg/l M&E Medium Strength Total Phosphorous (as P) 5.6 mg/l M&E Medium Strength Table 2.2 lists the existing PCC WWTP effluent limits for Outfall #001 as required by the SPDES Permit. Table 2.2 SPDES Permit Limits WWTP Discharge Parameter Limit Flow (30 day arithmetic mean) 20,000 gpd ph (range) Dissolved Oxygen (daily minimum) 4.0 mg/l CBOD 5 (30 day arithmetic mean) 12 mg/l, 2.3 lbs/day Suspended Solids - TSS (30 day arithmetic mean) 30 mg/l, 6.3 lbs/day Suspended Solids - TSS (7 day arithmetic mean) 45 mg/l & 9.4 lbs/day Dissolved Oxygen (daily minimum) 4.0 mg/l Solids, Settleable (daily maximum) 0.1 ml/l Coliform, Fecal (30 day geometric mean) Required May 15 to October / 100 ml Coliform, Fecal (7 day geometric mean) Required May 15 to October / 100 ml Chlorine Residual Required May 15 to October mg/l Delaware Engineering, D.P.C. 2

5 MacDonnell Heights Town Center DRAFT Existing Conditions Report - PCC WWTP 3.0 EXISTING WASTEWATER SYSTEM EVALUATION 3.1 Evaluation Approach An evaluation of each unit process utilized by the PCC WWTP was conducted utilizing the hydraulic loadings, a detailed review of operating data for influent organic loadings and knowledge of the SPDES discharge parameters. This review establishes and rates the actual capacity of each existing unit process under which SPDES compliance can consistently be achieved. The capacity of each unit process was evaluated based on Maximum Monthly Daily Flow (MMDF), Average Annual Daily Flow (ADF), Peak Day Flow (PDF), Peak Hourly Flow (PHF) and total organic loading. In accordance with current regulatory standards and good engineering practice each unit process is limited by specific hydraulic and/or organic design standards. The overall plant capacity is then rated as the capacity of the unit process with the most restrictive design capacity. The current SPDES permit flow limit is based on the daily average flow which for the purposes of this report is viewed as the ADF or annual average flow. The following unit processes were evaluated and the existing condition of each process is discussed below: 1. Main Influent Pump Station and Preliminary Treatment 2. Biological Treatment Process 3. Secondary Clarification 4. Return Activated Sludge 5. Effluent Filtration 6. Disinfection 7. Sludge Holding 3.2 Main Influent Pump Station and Preliminary Treatment All wastewater generated within the Poughkeepsie Business Park is collected at the influent pump station where the sewage receives preliminary treatment via a sewage grinder. The pump station then transfers the wastewater to the WWTP for treatment. To grind the sewage and reduce the solids size within the flow stream the pump station is equipped with a comminutor (grinder) with a reported peak hourly flow capacity of 315 gpm. Note that the characteristics of wastewater has evolved since the commissioning of the facility. The use of disposable wipes has become increasingly common and these wipes are introduced into wastewater systems with increasing frequency. Comminutors have shown to be relatively ineffective with these wipes. The main influent pump station is equipped with two submersible sanitary sewage pumps. Each pump is reportedly rated for 120 gpm at 42 Total Dynamic Head (TDH). The pump station Delaware Engineering, D.P.C. 3

6 MacDonnell Heights Town Center DRAFT Existing Conditions Report - PCC WWTP transfers wastewater directly to the aeration basins in the WWTP via a 4 cast iron forcemain. Regulatory standards require that the PHF of the pump station be carried with the largest pump out of service. With a peak factor of 4, the main influent pump station is rated for a PHF of 173,000 gpd and an ADF of 43,200 gpd. 3.3 Biological Treatment Process The PCC WWTP utilizes an activated sludge process known as extended aeration for the removal of BOD and TSS (organic matter) from the wastewater. This process involves mixing influent wastewater with micro-organisms well suited to biologically degrade the organic material in an oxygen rich environment. A simplified explanation of this process involves the microorganisms breaking down the organic matter by converting a portion of the organic matter (commonly referred to as BOD) into additional micro-organisms while also oxidizing a portion into carbon dioxide and water. The mixture of raw wastewater and micro-organisms is referred to as mixed liquor and the micro-organisms are referred to as activated sludge. The PCC WWTP is equipped with two aeration basins which are designed to operate in a parallel fashion. Aeration is provided within each basin via a surface aerator which transfers atmospheric oxygen into the mixed liquor. After biological treatment within the aeration basins, the mixed liquor flows to the secondary clarifiers where the activated sludge is separated from the treated water via gravity settling. Each aeration basin is approximately by and operates with a 10 side water depth and 24 of freeboard. Each basin has a working volume of 18,850 gallons and the system has a total aeration volume of 37,700 gallons. When following regulatory standards for an extended aeration activated sludge system, the organic (BOD) loading cannot exceed 15 lbs/day/1,000 ft 3 under the ADF condition. Following this standard, the aeration basin process is rated for 76 lbs BOD/day. With an influent BOD of 290 mg/l, the aeration basin system is rated for an ADF flow of 31,000 gpd. The PHF is not considered in the sizing of the aeration tanks. The design plans for the facility indicate each aeration basin is equipped with 3 horsepower surface aerators. However, the system currently has a 2 horsepower mechanical aerator installed in one of the aeration basins with the other basin offline and the mechanical aerator removed. When new, the mechanical aerators were rated to provide up to 2 lbs O2/hour (2 lbs O2/hp/hr Ten State Standards) to the mixed liquor. Therefore, with both systems in service, the PCC WWTP has an aeration capacity of 96 lbs O2/day. When considering the current influent BOD loading of 290 mg/l and TN loading of 35 mg/l, the aerators limit the rated MMDF of the facility to 19,300 gpd. With the single aerator in service, the system is rated for a MMDF of 9,650 gpd. The upper portions of the concrete walls show deterioration to levels which require concrete repairs/replacement. The floor and lower portions of the wall, which would have traditionally been protected with process water, appear to be in satisfactory condition and require very little repairs. Delaware Engineering, D.P.C. 4

7 MacDonnell Heights Town Center DRAFT Existing Conditions Report - PCC WWTP The steel components of the tank are corroded and require patching and/or replacement to extend the life of these systems. The system has only one functional aeration basin, with the aerator removed from the off-line aeration basin. The aerator on the functioning basins is in satisfactory condition. 3.4 Secondary Clarification The PCC WWTP provides solids separation (activated sludge and treated water) utilizing two x 11-5 secondary clarifiers. The clarifiers operate with approximately a 10 sidewater depth and a 24 of freeboard. The clarifiers accept mixed liquor from the aeration basins and decrease the velocity to a level that allows the activated sludge to settle to the bottom. The treated water discharges via an overflow weir on the top of the tank while the activated sludge settles into one of four sludge hoppers at the bottom of the clarifier. The settled sludge is then returned to the aeration basins for mixing with the organics in the raw wastewater. The activated sludge that is returned to the aeration basin is referred to as return activated sludge or RAS. As noted above, the activated sludge process converts organics in the wastewater to micro-organisms. To maintain a steady state condition of activated sludge in the system, a portion of the activated sludge settled within the secondary clarifier is wasted to the sludge holding tank. This sludge is referred to as waste activated sludge or WAS. Current regulatory standards require that secondary clarifiers following an extended aeration system not exceed a surface overflow rate at the PHF of 1,000 gpd/ ft 2 while also limiting the solids loading to 35 lbs/day/ ft 2. In terms of the clarifier surface area, the 270 ft 2 of total clarifier area is rated for a PHF of 270,000 gpd. When considering the system operating at the rated BOD loading of 76 lbs/day, an influent BOD concentration of 290 mg/l, a food:mass ratio of 0.15 and the RAS operating 150% of the ADF, the secondary clarifiers are limited to a PHF of 129,000 gpd to ensure the solids loading does not exceed 35 lbs/day/ ft 2. The clarifier capacity is limited based on the solids loading is rated for a PHF of 86,000 gpd. Similar to the aeration basins, the upper portions of the concrete walls show deterioration to levels which require concrete repairs/replacement. The floor and lower portions of the wall, which would have traditionally been protected with process water, appear to be in satisfactory condition and require very little repairs. The steel components of the tank are corroded and require patching and/or replacement to extend the life of these systems. The system has only one functional secondary clarifier, with the equipment removed from the off-line clarifier. 3.5 Return Activated Sludge The PCC WWTP is equipped with two return activated sludge (RAS) pumps which return activated sludge from the secondary clarifier to the aeration basins. Each pump is reportedly rated for 40 gpm at 20 TDH. Regulatory standards require RAS pumps to be capable of operating at all flow rates between 50% and 150% of the design ADF, with the system capable of returning up Delaware Engineering, D.P.C. 5

8 MacDonnell Heights Town Center DRAFT Existing Conditions Report - PCC WWTP to 150% of the facility s ADF flow with the largest pump out of service. With each pump rated capable of pumping at 57,600 gpd, the RAS system is rated for a plant ADF flow of 38,400 gpd. In addition to returning a portion of the activated sludge to the aeration basins, the RAS pumps are also utilized to waste a portion of the activated sludge to the solids processing system. 3.6 Effluent Filtration The extended aeration process utilized at the PCC WWTP will produce treated water with BOD and TSS of less than 30 mg/l. To achieve the required effluent limits of 12 mg/l BOD, the facility filters the secondary clarifier effluent utilizing a dosing system and two intermittent sand filters. The dosing system consists of a 20-1 x 8-6 dosing chamber which contains an alternating 5 siphon. The design dose is approximately 2,700 gallons per dose. The facility is equipped with two 40 x 40 intermittent sand filters. Regulatory standards for this type of sand filter vary. TR16 standards limit the peak hydraulic flow of this type of filter to 6.0 gpm/ft 2 with the largest filter out of service, while NYS2014 design standards limit the peak hydraulic flow to 10.0 gpm/ft 2 with the largest filter out of service. The filters therefore have a total PHF capacity ranging from 9,600-16,000 gpd with a unit out of service. 3.7 Disinfection The PCC WWTP provides disinfection of the wastewater by utilizing one 20-1 x 8-6 chlorine contact tank. The chlorine contact tank operates with approximately a 1-10 sidewater depth and provides a total volume of 2,340 gallons. Regulatory standards require a minimum of 15 minutes of contact time when operating under a PHF condition. With 2,340 gallons of contact tank, the contact tanks are rated for a PHF of 224,640 gpd. 3.8 Sludge Holding An activated sludge process such as the extended aeration process utilized at the PCC WWTP generates excess sludge which must be removed from the process. Table 12-7 of Metcalf & Eddy provides for a typical sludge yield from a medium strength wastewater in an extended aeration activated sludge system to be 0.8 lbs/dry solids/1,000 gallons. The PCC WWTP removes excess sludge (excess micro-organisms generated with the biodegradation of organic matter) utilizing one of the RAS pumps to divert a portion of the activated sludge to the sludge holding tank. The facility is equipped with one sludge holding tank, that is 12 long by 7-10 wide with an operating range up to 10-9 in depth, providing 7,550 gallons of capacity. Regulatory standards for sludge holding tanks are limited. This sizing review is based on a 30 day storage capacity. Assuming the sludge is thickened to 1.5% via gravity settling and decanting, the sludge holding tank has a total solids holding capacity of 945 lbs. Following Metcalf & Eddy Table Delaware Engineering, D.P.C. 6

9 MacDonnell Heights Town Center DRAFT Existing Conditions Report - PCC WWTP 3-18, medium strength wastewater from an extended aeration system will generate 0.8 lbs of waste activated sludge per 1,000 gallons of influent, which equates to an ADF rating of 39,400 gpd. 3.9 Unit Process Capacity Summary Table 3.1 presents a summary of the capacity of the existing PCC WWTP. Main Influent Pump Station Table 3.1 Existing Facility Capacity Summary Number of Pumps 2 Capacity / Pump Capacity ADF Capacity PHF (one pump in service) Aeration Basins Number of Units 2 Volume Each Total Volume Aeration System Tank Capacity ADF SBR Tank Capacity PHF Mechanical Aerators Capacity / Aerator Total Aerator Capacity (2 units in service) Aeration System Capacity ADF Aeration System Capacity MMDF Aeration System Capacity - PHF Secondary Clarifiers Number of Units gpm 43,200 gpd 173,000 gpd 18,850 gallons 37,700 gallons 31,000 gpd (influent BOD concentrations less than 290 mg/l will increase this rating) NA 2 (1 per tank) 48 lbs O2 / day 96 lbs O2 / day 16,080 gpd (influent BOD concentrations less than 290 mg/l will increase this rating) 19,300 gpd (influent BOD concentrations less than 290 mg/l will increase this rating) NA Clarifier Depth (ft) 10 ft Clarifier Surface Area Each (ft 2 ) 135 ft 2 Total Surface Area (ft 2 ) 270 ft 2 Clarifier Capacity ADF NA Clarifier Capacity MMDF NA Clarifier Capacity PHF 129,000 gpd (limited by solids loading influent BOD concentrations less than 290 mg/l increase this rating) Return Activated Sludge Pumps Number of Units 2 Capacity/Pump (gpm) 40 gpm Delaware Engineering, D.P.C. 7

10 MacDonnell Heights Town Center DRAFT Existing Conditions Report - PCC WWTP RAS Capacity ADF (gpd) 38,400 gpd RAS Capacity MMDF (gpd) NA RAS Capacity PHF (gpd) NA Effluent Filters Number of Units 2 Filter Area - Each 1,600 ft 2 Filter Area with largest unit out of service 1,600 ft 2 Filter Capacity - ADF NA Filter Capacity - MMDF NA Filter Capacity PHF 9,600-16,000 gpd Chlorine Contact Tanks Number of Units 1 Volume per Unit 2,340 gallons Total Capacity Disinfection - ADF NA Total Capacity Disinfection - MMDF NA Total Capacity Disinfection - PHF 224,640 gpd Solids Handling Sludge Holding Tank Number of Units 1 Sludge Holding Tank Volume 7,550gallons Sludge Holding Tank Capacity ADF 39,400 gpd Sludge Holding Tank Capacity MMDF NA Sludge Holding Tank Capacity PHF NA As noted above, the Poughkeepsie Corporate Center WWTP in its current configuration is severely limited by the size of the intermittent sand filters. These filters limit the peak hourly flow (PHF) to a maximum of 16,000 gpd. Upgrading the intermittent filters would result in the facility, with all equipment operational, being rated to accept and treat an annual average day flow (ADF) of 16,080 gpd, a maximum monthly daily flow (MMDF or maximum 30 day average flow) of 19,300 gpd and peak hourly flow (PHF) of 129,000 gpd. The system currently operates with one aeration basin and one secondary clarifier. The process equipment in the off-line aeration basin and clarifier is removed or inoperable. As a result, in its current condition the facility is rated for an ADF of 8,040 gpd, a MMDF of 9,650 and a PHF of 16,000 gpd. Delaware Engineering, D.P.C. 8

11 MacDonnell Heights Town Center DRAFT Existing Conditions Report - PCC WWTP FIGURES Delaware Engineering, D.P.C.

12 Pump Station "S ^_ PCC WWTP Figure 1 Poughkeepsie Corporate Center WWTP - Location Map Town of Poughkeepsie, Dutchess County SPDES Permit: NY Ü2,000 1, ,000 Feet Prepared by: Delaware Engineering DPC, February 2017 Sources: NYSDOT 7.5' Digital Raster Quads: AA47 Pleasant Valley and AA48 Poughkeepsie

13 Tu rnp ike 168 Du tch es s 7' 6 1 ' 1 Bre tt P lac e ' 67 Pump Station FF Elev ~171' PCC WWTP FF Elev ~175' 167' R mo d oa Floodway 100 Year Flood Zone 500 Year Flood Zone 16 Old Degarmo Road r ga De Legend 5' Base Flood Elevation Figure 2 Poughkeepsie Corporate Center WWTP - Flood Zones Town of Poughkeepsie, Dutchess County SPDES Permit: NY Ü Feet Prepared by: Delaware Engineering DPC, February 2017 Sources: FEMA Dutchess County DFIRM 2012 NYS Digital Ortho Imagery Spring ' contours created from NYS 1 meter DEMs

14 MacDonnell Heights Town Center DRAFT Existing Conditions Report - PCC WWTP APPENDIX A Poughkeepsie Corporate Center SPDES Permit # NY Delaware Engineering, D.P.C.

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32 MacDonnell Heights Town Center Town of Poughkeepsie, Dutchess County, New York Poughkeepsie Corporate Center Wastewater Treatment Plant DRAFT Environmental Impact Statement Facility Plan Prepared for: MHTC Development, LLC 199 West Road, Suite 101 Pleasant Valley, NY Prepared by: Delaware Engineering, D.P.C. 28 Madison Avenue Extension Albany, New York May 2017

33 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP TABLE OF CONTENTS Section Page 1.0 INTRODUCTION Existing Facility Overview and History Flood Zone Regulatory and Design Standards EXISTING WWTP HYDRAULIC AND ORGANIC LOADING Existing Loading and SPDES Permit EXISTING WASTEWATER SYSTEM EVALUATION Evaluation Approach Main Influent Pump Station and Preliminary Treatment Biological Treatment Process Secondary Clarification Return Activated Sludge Effluent Filtration Disinfection Sludge Holding Unit Process Capacity Summary WASTEWATER TREATMENT PLANT UPGRADE Design Treatment Process Overview Hydraulic Loading, Solids Loadings and Anticipated SPDES Permit UPGRADE PLAN Hydraulic and Organic Load Capacity Upgraded Treatment Facility WWTP Main Influent Pump Station Headworks - Influent Screening and Flow Equalization Biological Treatment Phosphorous Removal Sanitary Disinfection and Post-Aeration Post-Aeration Sludge Handling Facilities WWTP Discharge Phasing Plan CONSTRUCTION OPERATIONS OPERATION AND MAINTENANCE 16 Delaware Engineering, D.P.C. i

34 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP TABLES Table 2.1 Historical Influent Loading 3 Table 2.2 SPDES Permit Limits WWTP Discharge 3 Table 3.1 Existing Facility Capacity Summary 8 Table 4.1 Design Hydraulic Loading MacDonnell Heights Town Center 11 Table 4.2 Design Hydraulic Loading PCC WWTP 12 Table 4.3 PCC WWTP Design Flows 12 Table 4.4 Design Influent Organic Loading 12 Table 4.5 Draft / Anticipated SPDES Permit Limits 13 Table 5.1 PCC WWTP Design Capacity 14 Figure 1 Figure 2 Figure PR-1 FIGURES Location Map Flood Zone Map Process Schematic Existing System APPENDICES Appendix A Poughkeepsie Corporate Center WWTP SPDES Permit # NY Appendix B Poughkeepsie Corporate Center WWTP Draft SPDES Permit Limits Exhibit A EXHIBITS Design Guidelines for Wastewater Facilities, Maryland Department of the Environment - Engineering and Capital Projects Program, 2013 Delaware Engineering, D.P.C. ii

35 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP 1.0 INTRODUCTION 1.1 Existing Facility Overview and History The existing Poughkeepsie Corporate Center Wastewater Treatment Plant (PCC WWTP) is located in the Town of Poughkeepsie at 900 Dutchess Turnpike (U.S. Route 44). A Location Map is included as Figure 1. The PCC WWTP was constructed in the 1960s with a permitted capacity of 20,000 gallons per day (gpd) and provides sewer service to the Poughkeepsie Business Park. The facility discharges to the Wappingers Creek and is regulated via State Pollutant Discharge Elimination System (SPDES) Permit # NY with is attached as Appendix A. Currently, the flow to the facility is significantly less than the permitted capacity of the system. While permitted for 20,000 gpd, the facility treats approximately 2,900 gpd. As a result of the low flows to the system only a portion of the facility is utilized. The MacDonnell Heights Town Center project intends to upgrade the PCC WWTP and utilize this facility to provide the required wastewater treatment for the Town Center project. 1.2 Flood Zone The PCC WWTP site is located within the 100 Year Flood Zone AE according to FEMA Flood Insurance Rate Map (FIRM) Number 36027C0378E for the Towns of La Grange and Poughkeepsie, effective May 2, The Base Flood Elevation at the WWTP is approximately 167 referenced to the North American Vertical Datum 1988 (NAVD88). Figure 2 shows the FEMA Digital FIRM layers including the Floodway, Flood Zones and Base Flood Elevations, 2 foot contours created from NYS 1 meter DEMs, and 2013 NYS orthoimagery of the site area. The PCC wastewater facilities where designed and constructed to withstand a 100 year flood event with no physical damage. The finished floor elevation is approximately 175 at the wastewater treatment plant and approximately 171 at the pump station. The treatment capabilities of the facility could be reduced as the chlorine contact tank would surcharge and the effluent filters would approach a surcharge condition (sand elevation ~ ) during a 100 year flood event. Regulatory standards require that the facility be protected from physical damage during a 100 year event. The existing PCC WWTP meets these requirements and any future improvements must be designed to ensure the facility is protected from damage during a 100 year flood event. 1.3 Regulatory and Design Standards This Engineering Report is prepared in conformance with the following standards: Recommended Standards for Wastewater Facilities, Great Lakes-Upper Mississippi River Board of State Public Health & Environmental Managers, 2014, (commonly referred to as Ten States Standards) Delaware Engineering, D.P.C. 1

36 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP TR-16 Guides for the Design of Wastewater Treatment Work, New England Interstate Water Pollution Control Commission, 2016, (referred to as TR16) New York State Design Standards for Intermediate Sized Wastewater Treatment Systems, NYS Department of Environmental Conservation, 2014, (referred to as DEC2014) Wastewater Engineering Treatment and Resource Recovery, 5 th Edition, Metcalf & Eddy / EACOM, 2014 (referred to as M&E 2014) Wastewater Engineering Treatment, Disposal and Reuse, 3 rd Edition, Metcalf & Eddy, Inc., 1991 (referred to as M&E 1991) Design Guidelines for Wastewater Facilities, Maryland Department of the Environment, Engineering and Capital Projects Program, 2013 (referred to as Maryland2013) Delaware Engineering, D.P.C. 2

37 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP 2.0 EXISTING WWTP HYDRAULIC AND ORGANIC LOADING 2.1 Existing Loading and SPDES Permit SPDES Permit # NY provides discharge limits for three distinct outfalls. The WWTP is regulated via Outfall #001. Outfalls #002 and #003 are related to cooling water, softener backwash, etc. from specific processes within other facilities in the business park. These outfalls are unrelated to the functioning of the WWTP and this report focuses solely on Outfall #001. Table 2.1 lists the influent loading characteristics for the PCC WWTP which were used in the evaluation of the existing facility. These loading characteristic are based on a combination of the influent testing results along with typical medium strength wastewater in accordance with Table 3-18 of M&E 2014 and are as follows: Parameter Table 2.1 Historical Influent Loading Historical Influent Concentration Current Annual Average Daily Flow (ADF) 2,900 gpd ( ) BOD 5 TSS NH3 (as N) TN (as N) Total Phosphorous (as P) 290 mg/l (2014 data) 380 mg/l (2014 data) 20 mg/l M&E Medium Strength 35 mg/l M&E Medium Strength 5.6 mg/l M&E Medium Strength Table 2.2 lists the existing PCC WWTP effluent limits for Outfall #001 as required by the SPDES Permit. Parameter Flow (30 day arithmetic mean) Table 2.2 SPDES Permit Limits WWTP Discharge Limit 20,000 gpd ph (range) Dissolved Oxygen (daily minimum) CBOD 5 (30 day arithmetic mean) Suspended Solids - TSS (30 day arithmetic mean) 4.0 mg/l 12 mg/l, 2.3 lbs/day 30 mg/l, 6.3 lbs/day Suspended Solids - TSS (7 day arithmetic mean) 45 mg/l & 9.4 lbs/day Dissolved Oxygen (daily minimum) Solids, Settleable (daily maximum) Coliform, Fecal (30 day geometric mean) Required May 15 to October 15 Coliform, Fecal (7 day geometric mean) Required May 15 to October 15 Chlorine Residual Required May 15 to October mg/l 0.1 ml/l 200 / 100 ml 400 / 100 ml mg/l Delaware Engineering, D.P.C. 3

38 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP 3.0 EXISTING WASTEWATER SYSTEM EVALUATION 3.1 Evaluation Approach An evaluation of each unit process utilized by the PCC WWTP was conducted using the hydraulic loadings, a detailed review of operating data for influent organic loadings and knowledge of the SPDES discharge parameters. This review establishes and rates the actual capacity of each existing unit process under which SPDES compliance can consistently be achieved. The capacity of each unit process was evaluated based on Average Annual Daily Flow (ADF), Maximum Monthly Daily Flow (MMDF), Peak Hourly Flow (PHF) and total organic loading. In accordance with current regulatory standards and good engineering practice each unit process is limited by specific hydraulic and/or organic design standards. The overall plant capacity is then rated as the capacity of the unit process with the most restrictive design capacity. The current SPDES permit flow limit is based on the maximum monthly daily flow. The flow fluctuation design factors utilized in this evaluation are as follows: Flow Fluctuation Design Factors Multiples of the ADF Flow: 1. Maximum Monthly Daily Flow: 1.2 X ADF (Table 2-8 of M&E 1991) 2. Peak Hourly Flow (no flow equalization): 4.0 X ADF (Ten States Standards) A Process Schematic of the existing system is included as Figure PR-1. The following unit processes were evaluated and the existing condition of each process is discussed below: 1. Main Influent Pump Station and Preliminary Treatment 2. Biological Treatment Process 3. Secondary Clarification 4. Return Activated Sludge 5. Effluent Filtration 6. Disinfection 7. Sludge Holding 3.2 Main Influent Pump Station and Preliminary Treatment All wastewater generated within the Poughkeepsie Business Park is collected at the influent pump station where the sewage receives preliminary treatment via a sewage grinder. The pump station then transfers the wastewater to the WWTP for treatment. To grind the sewage and reduce the solids size within the flow stream the pump station is equipped with a comminutor (grinder) with a reported peak hourly flow capacity of 315 gpm. Note that the characteristics of wastewater has evolved since the commissioning of the facility. The use of disposable wipes has become increasingly common and these wipes are introduced into Delaware Engineering, D.P.C. 4

39 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP wastewater systems with increasing frequency. Comminutors have been shown to be relatively ineffective with these wipes. The main influent pump station is equipped with two submersible sanitary sewage pumps. Each pump is reportedly rated for 120 gpm at 42 Total Dynamic Head (TDH). The pump station transfers wastewater directly to the aeration basins in the WWTP via a 4 cast iron forcemain. Regulatory standards require that the PHF of the pump station be carried with the largest pump out of service. The main influent pump station is rated for a PHF of 173,000 gpd and an associated ADF of 43,200 gpd. 3.3 Biological Treatment Process The PCC WWTP utilizes an activated sludge process known as extended aeration for the removal of BOD and TSS (organic matter) from the wastewater. This process involves mixing influent wastewater with micro-organisms well suited to biologically degrade the organic material in an oxygen rich environment. A simplified explanation of this process involves the microorganisms breaking down the organic matter by converting a portion of the organic matter (commonly referred to as BOD) into additional micro-organisms while also oxidizing a portion into carbon dioxide and water. The mixture of raw wastewater and micro-organisms is referred to as mixed liquor and the micro-organisms are referred to as activated sludge. The PCC WWTP is equipped with two aeration basins which are designed to operate in a parallel fashion. Aeration is provided within each basin via a surface aerator which transfers atmospheric oxygen into the mixed liquor. After biological treatment within the aeration basins, the mixed liquor flows to the secondary clarifiers where the activated sludge is separated from the treated water via gravity settling. Each aeration basin is approximately by and operates with a 10 side water depth and 24 of freeboard. Each basin has a working volume of 18,850 gallons and the system has a total aeration volume of 37,700 gallons. When following regulatory standards for an extended aeration activated sludge system, the organic (BOD) loading cannot exceed 15 lbs/day/1,000 ft 3 under the ADF condition. Following this standard, the aeration basin process is rated for 76 lbs BOD/day. With an influent BOD of 290 mg/l, each aeration basin is rated for an ADF flow of 15,500 gpd. The combination of both aeration results in the aeration basin system being rated for an ADF flow of 31,000 gpd. The PHF is not considered in the sizing of the aeration tanks. The design plans for the facility indicate each aeration basin is equipped with 3 horsepower surface aerators. However, the system currently has a 2 horsepower mechanical aerator installed in one of the aeration basins with the other basin offline and the mechanical aerator removed. Following Ten State Standards, each mechanical aerator is rated to provide up to 4 lbs O2/hour (2 lbs O2/hp/hr) in clean water (SOR). With the system operating with a dissolved oxygen concentration of 2 mg/l, an alpha of 0.85 and a beta of 0.9 (alpha and beta are correction factors which reflect Delaware Engineering, D.P.C. 5

40 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP the oxygen transfer into wastewater versus clean water), each aerator is capable of transferring 2.4 lbs O2/hr into the aeration basin. Therefore, with both systems in service the PCC WWTP has an aeration capacity of 115 lbs O2/day. When considering the current influent BOD loading of 290 mg/l and TN loading of 35 mg/l, the aerators limit the rated MMDF of the facility to 23,140 gpd. With the single aeration basin in service, the system is rated for a MMDF of 11,570 gpd. The upper portions of the concrete walls show deterioration to extents that require concrete repairs/replacement. The floor and lower portions of the wall, which would have traditionally been protected with process water, appear to be in satisfactory condition and require very little repairs. The steel components of the tank are corroded and require patching and/or replacement to extend the life of these systems. The system has only one functional aeration basin, with the aerator removed from the off-line aeration basin. The aerator on the functioning basins is in satisfactory condition. 3.4 Secondary Clarification The PCC WWTP provides solids separation (activated sludge and treated water) utilizing two x 11-5 secondary clarifiers. The clarifiers operate with approximately 10 of sidewater depth and a 24 of freeboard. The clarifiers accept mixed liquor from the aeration basins and decrease the velocity to a level that allows the activated sludge to settle to the bottom. The treated water discharges via an overflow weir on the top of the tank while the activated sludge settles into one of four sludge hoppers at the bottom of the clarifier. The settled sludge is then returned to the aeration basins for mixing with the organics in the raw wastewater. The activated sludge that is returned to the aeration basin is referred to as return activated sludge or RAS. As noted above, the activated sludge process converts organics in the wastewater to micro-organisms. To maintain a steady state condition of activated sludge in the system, a portion of the activated sludge settled within the secondary clarifier is wasted to the sludge holding tank. This sludge is referred to as waste activated sludge or WAS. Current regulatory standards require that secondary clarifiers following an extended aeration system not exceed a surface overflow rate at the PHF of 1,000 gpd/ ft 2 while also limiting the solids loading to 35 lbs/day/ ft 2. In terms of the clarifier surface area, each clarifier has 135 ft 2 of clarifier area and an associated PHF of 135,000 gpd. Both clarifiers in service provide a PHF rating of 270,000 gpd. When considering the system operating at the rated BOD loading of 76 lbs/day, an influent BOD concentration of 290 mg/l, a food:mass ratio of 0.15 and the RAS operating 150% of the ADF, each secondary clarifiers is limited to a PHF of 64,500 gpd to ensure the solids loading does not exceed 35 lbs/day/ ft 2. The total clarifier capacity (both clarifiers in service) is limited based on the solids loading is rated for a PHF of 129,000 gpd. Similar to the aeration basins, the upper portions of the concrete walls show deterioration to extents that require concrete repairs/replacement. The floor and lower portions of the wall, which would have traditionally been protected with process water, appear to be in satisfactory condition and Delaware Engineering, D.P.C. 6

41 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP require very little repairs. The steel components of the tank are corroded and require patching and/or replacement to extend the life of these systems. 3.5 Return Activated Sludge The PCC WWTP is equipped with two return activated sludge (RAS) pumps which return activated sludge from the secondary clarifier to the aeration basins. Each pump is reportedly rated for 40 gpm at 20 TDH. Regulatory standards require RAS pumps to be capable of operating at all flow rates between 50% and 150% of the design ADF, with the system capable of returning up to 150% of the facility s ADF flow with the largest pump out of service. With each pump rated capable of pumping at 57,600 gpd, the RAS system is rated for a plant ADF flow of 38,400 gpd. In addition to returning a portion of the activated sludge to the aeration basins, the RAS pumps are also utilized to waste a portion of the activated sludge to the solids processing system. 3.6 Effluent Filtration The extended aeration process utilized at the PCC WWTP will produce treated water with BOD and TSS of less than 30 mg/l. To achieve the required effluent limits of 12 mg/l BOD, the facility filters the secondary clarifier effluent utilizing a dosing system and two intermittent sand filters. The dosing system consists of a 20-1 x 8-6 dosing chamber which contains an alternating 5 siphon. The design dose is approximately 2,700 gallons per dose. The facility is equipped with two 40 x 40 intermittent sand filters. Regulatory standards limit the peak hydraulic flow to 10.0 gpm/ft 2 with the largest filter out of service. The filters therefore have a total PHF capacity of 16,000 gpd with a unit out of service. 3.7 Disinfection The PCC WWTP provides disinfection of the wastewater by utilizing one 20-1 x 8-6 chlorine contact tank. The chlorine contact tank operates with approximately a 1-10 sidewater depth and provides a total volume of 2,340 gallons. Regulatory standards require a minimum of 15 minutes of contact time when operating under a PHF condition. With 2,340 gallons of contact tank, the contact tanks are rated for a PHF of 224,640 gpd. 3.8 Sludge Holding An activated sludge process such as the extended aeration process utilized at the PCC WWTP generates excess sludge which must be removed from the process. Table 13-7 of M&E 2014 provides for a typical sludge yield from a medium strength wastewater in an extended aeration activated sludge system to be 0.8 lbs/dry solids/1,000 gallons. The PCC WWTP removes excess sludge (excess micro-organisms generated with the biodegradation of organic matter) utilizing one Delaware Engineering, D.P.C. 7

42 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP of the RAS pumps to divert a portion of the activated sludge to the sludge holding tank. The facility is equipped with one sludge holding tank that is 12 long by 7-10 wide with an operating range up to 10-9 in depth, providing 7,550 gallons of capacity. Regulatory standards for sludge holding tanks are limited. This sizing review is based on a 30 day storage capacity. Assuming the sludge is thickened to 1.5% via gravity settling and decanting, the sludge holding tank has a total solids holding capacity of 945 lbs. Following Table 13-7 of M&E 2014, medium strength wastewater from an extended aeration system will generate 0.8 lbs of waste activated sludge per 1,000 gallons of influent, which equates to an ADF rating of 39,400 gpd. 3.9 Unit Process Capacity Summary Table 3.1 presents a summary of the capacity of the existing PCC WWTP. Table 3.1 Existing Facility Capacity Summary Main Influent Pump Station Number of Pumps 2 Capacity / Pump 120 gpm Capacity ADF 43,200 gpd Capacity PHF (one pump in service) 173,000 gpd Aeration Basins Number of Units 2 Volume Each 18,850 gallons Total Volume 37,700 gallons Aeration System Tank Capacity ADF 31,000 gpd (influent BOD concentrations less than 290 mg/l will increase this rating) Aeration Tank Capacity PHF NA Mechanical Aerators 2 (1 per tank) Capacity / Aerator 58 lbs O 2 / day Total Aerator Capacity (2 units in service) 115 lbs O 2 / day Aeration System Capacity ADF 19,280 gpd (influent BOD concentrations less than 290 mg/l will increase this rating) Aeration System Capacity MMDF 23,140 gpd (influent BOD concentrations less than 290 mg/l will increase this rating) Aeration System Capacity - PHF NA Secondary Clarifiers Number of Units 2 Clarifier Depth (ft) 10 ft Clarifier Surface Area Each (ft 2 ) 135 ft 2 Total Surface Area (ft 2 ) 270 ft 2 Delaware Engineering, D.P.C. 8

43 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP Clarifier Capacity ADF Clarifier Capacity MMDF Clarifier Capacity PHF Return Activated Sludge Pumps Number of Units 2 Capacity/Pump (gpm) RAS Capacity ADF (gpd) RAS Capacity MMDF (gpd) RAS Capacity PHF (gpd) Effluent Filters Number of Units 2 NA NA 129,000 gpd (limited by solids loading influent BOD concentrations less than 290 mg/l increase this rating) 40 gpm 38,400 gpd NA NA Filter Area - Each 1,600 ft 2 Filter Area with largest unit out of service 1,600 ft 2 Filter Capacity - ADF Filter Capacity - MMDF Filter Capacity PHF Chlorine Contact Tanks Number of Units 1 Volume per Unit Total Capacity Disinfection - ADF Total Capacity Disinfection - MMDF Total Capacity Disinfection - PHF Solids Handling Sludge Holding Tank Number of Units 1 Sludge Holding Tank Volume Sludge Holding Tank Capacity ADF Sludge Holding Tank Capacity MMDF Sludge Holding Tank Capacity PHF NA NA 16,000 gpd 2,340 gallons NA NA 224,640 gpd 7,550 gallons 39,400 gpd NA NA As noted above, the PCC WWTP in its current configuration is severely limited by the size of the intermittent sand filters. These filters limit the peak hourly flow (PHF) to 16,000 gpd. Upgrading the intermittent filters would result in the facility, with all equipment operational, being rated to accept and treat an annual average day flow (ADF) of 19,280 gpd, a maximum monthly daily flow (MMDF or maximum 30 day average flow) of 23,140 gpd and peak hourly flow (PHF) of 129,000 gpd. The system currently operates with one aeration basin and one secondary clarifier. The process equipment in the off-line aeration basin and clarifier is removed or inoperable. As a result, the facility in its current condition is rated for an ADF of 9,640 gpd, a MMDF of 11,570 gpd and a PHF of 16,000 gpd. Delaware Engineering, D.P.C. 9

44 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP 4.0 WASTEWATER TREATMENT PLANT UPGRADE 4.1 Design Treatment Process Overview The PCC WWTP will be upgraded to accommodate the wastewater generated by the MacDonnell Heights Town Center. The upgraded facility will be designed to meet treatment objectives required by a modified SPDES permit and will continue to discharge to the Wappingers Creek. 4.2 Hydraulic Loading, Solids Loadings and Anticipated SPDES Permit The MacDonnell Heights Town Center project includes a mixture of residential and commercial uses. To the extent possible, standards in DEC2014 were utilized to determine the design sanitary sewer flow rates for the development. Following the procedures outlined in Method 3 in this standard, historical water use data from similar developments were used to determine the design flow rates from the residential and medical facilities within the development. Typical Hydraulic Loading Rates listed in Table B-3 were utilized to determine design flow rates for proposed uses without readily available and reliable water usage data. In addition, Maryland2013 was referenced to determine appropriate design flows for general commercial uses such as general office, financial and service spaces. This standard was utilized rather than the DEC2014 standard as this standard provides design wastewater generation rates based on gross square footage. DEC2014 projects water usages for these types of spaces on specific components such as number of employees, number of stations, etc. For example, the water usage for the commercial areas designated as Service was viewed as barber shop type service and assigned a water projected water demand of 0.20 gpd/ft 2 in accordance with Maryland2013. DEC2014 projects water usage for a barber shop type service on a per station basis. Given the level of uncertainty regarding the final tenant types, projecting flows bases on a gross square footage is appropriate. This standard provides typical water usage based on gross square footage and is attached as Exhibit A. The design flow rates based on DEC2014 Method 3 using historical water use data are as follows: Residential Apartments (Historical Data - Brookside Meadows Luxury Rental Community, Pleasant Valley NY) Number of Apartments: 302 Total Number of Bedrooms: 545 % Occupied: 98% Bedrooms in Count: 534 (98% of 545) Annual Average Water Usage: 37,180 gpd Annual Average Water Usage / Bedroom: 70 gpd Projected Maximum Monthly Daily Flow (MMDF): 84 gpd (1.2 x ADF based on M&E 1991, Table 2-8) Delaware Engineering, D.P.C. 10

45 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP Design for Facility not to exceed 95% permitted capacity (DEC flow management requirements): 88 gpd Design for MMDF of 90 gpd / bedroom Medical Office Building (Historical Data - Poughkeepsie Medical Office Building) Square Footage: 57,000 ft 2 % Occupied: 100% Annual Average Water Usage: 2,893 gpd Annual Average Water Usage / ft 2 : 0.05 gpd/ft 2 : Projected Maximum Monthly Daily Flow (MMDF): 0.06 gpd/ft 2 (1.2 x ADF based on M&E 1991, Table 2-8) Design for 95% capacity (DEC flow management requirements): gpd/ft 2 Design for MMDF of 0.06 gpd/ft 2 The projected hydraulic loading rates from the MacDonnell Heights Town Center at full buildout is as follows: Table 4.1 Design Hydraulic Loading MacDonnell Heights Town Center Use # of Units Flow/Unit (gpd) Total Flow (gpd on 30 day average basis) Apartments 650 Bedrooms 90 gpd / bedroom* 58,500 Restaurant/Café 469 Seats 28 gpd / seat ** 13,130 General Retail 19,500 ft gpd/ft 2 ** 1,560 Service 11,000 ft gpd/ft 2 *** 2,200 Medical Office 18,000 ft gpd/ft 2 * 1,080 Bank/Financial 3,500 ft gpd/ft 2 *** 140 General Office 18,500 ft gpd/ft 2 *** 1,665 Day Care 80 Children 16 gpd/child** 1,280 Maintenance/Service Building 9,000 ft gpd/ft 2 *** 270 Total Flow Full Buildout 79,825 * DEC 2014 Method 3, Historical Data ** DEC 2014 Table B-3, Typical Per-Unit Hydraulic Loading Rates *** Maryland 2013 Delaware Engineering, D.P.C. 11

46 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP The Poughkeepsie Business Park currently produces 2,900 gpd of wastewater, however the PCC WWTP upgrade project will preserve a total of 12,500 gpd of capacity (current flow plus future demand) for the business park s use. Table 4.2 Design Hydraulic Loading PCC WWTP Source Total Flow (gpd on 30 day average basis) MacDonnell Heights Town Center 79,825 Poughkeepsie Business Park 12,500 Future Growth 2,675 Design Flow 95,000 Table 4.3 PCC WWTP Design Flows Design Flow Average Daily Flow (ADF) (365 day average) Maximum Monthly Daily Flow (Maximum 30 Day Average X ADF) Peak Hourly Flow (4.0 X ADF) Gallons per Day 79,170 95, ,700 Given that the current organic loading data for the existing facility accounts for only 3% of the design flow for an expanded PCC WWTP, the design organic loading is based on more typical strength municipal wastewater. The design organic loading is as follows: Table 4.4 Design Influent Organic Loading Parameter BOD 5 TSS NH3 (as N) TN (as N) Total Phosphorous (as P) Design Influent Concentration 250 mg/l 250 mg/l 35 mg/l 50 mg/l 8 mg/l Delaware Engineering, D.P.C. 12

47 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP Draft NYSDEC SPDES permit limits for the MacDonnell Heights Town Center project are included in Appendix B and are summarized below. Table 4.5 Draft / Anticipated SPDES Permit Limits Parameter Flow (30 day arithmetic mean) Limit 95,000 gpd ph (range) Dissolved Oxygen (daily minimum) BOD 5 (30 day arithmetic mean) Suspended Solids - TSS (30 day arithmetic mean) Nitrogen, Ammonia (as NH 3) (daily maximum summer months) Dissolved Oxygen (daily minimum) Solids, Settleable (daily maximum) Total Phosphorous Coliform, Fecal (30 day geometric mean) Required May 15 to October 15 Coliform, Fecal (7 day geometric mean) Required May 15 to October 15 Temperature 4.0 mg/l 10 mg/l 20 mg/l 2.0 mg/l 4.0 mg/l 0.1 ml/l 0.62 mg/l 200 / 100 ml 400 / 100 ml Monitor Delaware Engineering, D.P.C. 13

48 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP 5.0 UPGRADE PLAN 5.1 Hydraulic and Organic Load Capacity The capacity of each unit process within the upgraded facility will be based on the applicable Average Annual Daily Flow (ADF), Maximum Monthly Daily Flow (MMDF), and/or Peak Hydraulic Flow (PHF). The design flow conditions are represented in Table 5.1. Table 5.1 PCC WWTP Design Capacity Annual Average Daily Flow (ADF) Parameter Maximum Monthly Daily Flow (MMDF) Permitted Flow Peak Hourly Flow (Before Equalization peak hydraulic capacity of pump station and influent screening) Peak Hourly Flow (After Equalization peak hydraulic capacity of equalization, MBR process, disinfection and post-aeration) Flow 79,170 gpd 95,000 gpd 316,700 gpd 142,500 gpd In accordance with current regulatory standards and good engineering practice, each unit process requires a specific hydraulic design standard. The overall plant capacity is then rated as the capacity of the unit process with the most restrictive design capacity. The anticipated SPDES permit that sets the discharge value at 95,000 gpd is anticipated to be based on a 30 day average flow (MMDF). In accordance with Table 2-8 of M&E 1991 the maximum monthly daily flow (maximum 30 day average or MMDF) is 120% larger than the annual average daily flow (ADF). As such, the PCC WWTP is designed for an ADF of 79,170 GPD and an associated MMDF of 95,000 GPD. The permitted flow is anticipated to be based on the MMDF and is 95,000 gpd. 5.2 Upgraded Treatment Facility The following narratives generally describe the illustrated process designs WWTP Main Influent Pump Station All wastewater generated within the existing Poughkeepsie Business Park and the MacDonnell Heights Town Center will be collected at the existing influent pump station. This station will be upgraded with replacement pumps and controls rated for the PHF of the system prior to flow equalization. Delaware Engineering, D.P.C. 14

49 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP Headworks - Influent Screening and Flow Equalization. The PCC WWTP will be equipped with influent screening in accordance with all applicable design standards. Flow equalization will be provided as required Biological Treatment The upgraded PCC WWTP will utilize a biological treatment process for removal of BOD, TSS, and ammonia Phosphorous Removal Filtration is required to achieve the required TSS and BOD removal along with the required total phosphorus limits. NYSDEC has indicated that the total phosphorous limit of the upgraded PCC WWTP will be 0.62 mg/l. It is proposed that this limit will be achieved utilizing sand filtration or an equivalent technology. To achieve the required low phosphorous limits, a metal salt such as polyaluminum chloride (PAC) will be injected at various locations throughout the process Sanitary Disinfection and Post-Aeration The PCC WWTP will be equipped with a disinfection systems in accordance with all applicable design standards Post-Aeration Post-aeration will be added to the facility as required to meet the SPDES permit limit of 4.0 mg/l of dissolved oxygen Sludge Handling Facilities The PCC WWTP will be equipped with sludge handling facilities in accordance with all applicable design standards WWTP Discharge The upgraded PCC WWTP will continue to discharge to the Wappingers Creek via the existing 6 outfall. The existing 6 outfall piping flows as an open channel gravity pipe line and has sufficient capacity for the upgraded facility as follows: Delaware Engineering, D.P.C. 15

50 MacDonnell Heights Town Center DRAFT EIS Facility Plan - PCC WWTP Effluent Piping Capacity Calculations 6 CI Q = 1.49 * A * R^(2/3) * S ^(1/2) / n Manning s Equation n = d/d = 1 A/D^2 = R/D = 0.25 D = 0.5 R = 0.13 A = 0.20 S = 0.01 Q = 0.5 ft^3/sec Q = 219 GPM Phasing Plan Construction of the Town Center Development can commence and buildings can be occupied utilizing the existing WWTP with no changes. The existing facility in its current condition is rated for an ADF of 9,640 gpd. The facility s current ADF loading is 2,900 gpd with up to 6,740 gpd of capacity remaining. The construction of the upgrades will occur in a phased fashion such that capacity is constructed as the development is expanded. 6.0 CONSTRUCTION OPERATIONS A construction sequence will be prepared as part of detailed design. 7.0 OPERATION AND MAINTENANCE An Operations and Maintenance Manual will be prepared and provided to operators during the start-up period. Training on all new equipment will also be provided by equipment manufacturers. Delaware Engineering, D.P.C. 16

51 MacDonnell Heights Town Center DRAFT Facility Plan - PCC WWTP FIGURES Delaware Engineering, D.P.C.

52 Pump Station "S ^_ PCC WWTP Figure 1 Poughkeepsie Corporate Center WWTP - Location Map Town of Poughkeepsie, Dutchess County SPDES Permit: NY Ü2,000 1, ,000 Feet Prepared by: Delaware Engineering DPC, February 2017 Sources: NYSDOT 7.5' Digital Raster Quads: AA47 Pleasant Valley and AA48 Poughkeepsie

53 Tu rnp ike 168 Du tch es s 7' 6 1 ' 1 Bre tt P lac e ' 67 Pump Station FF Elev ~171' PCC WWTP FF Elev ~175' 167' R mo d oa Floodway 100 Year Flood Zone 500 Year Flood Zone 16 Old Degarmo Road r ga De Legend 5' Base Flood Elevation Figure 2 Poughkeepsie Corporate Center WWTP - Flood Zones Town of Poughkeepsie, Dutchess County SPDES Permit: NY Ü Feet Prepared by: Delaware Engineering DPC, February 2017 Sources: FEMA Dutchess County DFIRM 2012 NYS Digital Ortho Imagery Spring ' contours created from NYS 1 meter DEMs

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55 MacDonnell Heights Town Center DRAFT Facility Plan - PCC WWTP APPENDIX A Poughkeepsie Corporate Center SPDES Permit # NY Delaware Engineering, D.P.C.

56 New York State Department of Environmental Conservation Division of Environmental Permits NYSDEC HEADQUARTERS 625 BROADWAY ALBANY, NY (518) SPDES PERMIT RENEWAL 2/14/2017 JAMES HART POUGHEEPSIE BUSINESS PAR 900 DUTCHESS TPE POUGHEEPSIE NY Permittee Name: POUGHEEPSIE BUSINESS PAR LLC Facility Name: POUGHEEPSIE CORP CENTER Ind. Code: 9999 County: DUTCHESS DEC ID: /00001 SPDES No.: NY Permit Effective Date: 4/1/2017 Permit Expiration Date: 3/31/2022 Dear Permittee, The State Pollutant Elimination System (SPDES) permit renewal for the facility referenced above is approved with the new effective and expiration dates. This letter together with the previous valid permit for this facility effective on 04/01/2012 and any subsequent modifications constitute authorization to discharge wastewater in accordance with all terms, conditions and limitations specified in the previously issued permit(s). As a reminder, SPDES permits are renewed at a central location in Albany in order to make the process more efficient. All other concerns with your permit, including applications for permit modification or transfer to a new owner, a name change, and other questions, should be directed to: Regional Permit Administrator NYSDEC Region 3 Headquarters 21 S Putt Corners Rd New Paltz, NY (845) If you have already filed an application for modification of your permit, it will be processed separately by that office If you have questions concerning this permit renewal, please contact LINDY SUE CZUBERNAT at (518) 402- Sincerely, Stuart M. Fox Deputy Chief Permit Administrator cc: RPA RWE BWP BWC File EPA

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