July 2014 – Peirce Island WWTF Upgrade Preliminary (30 Percent)

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TABLE OF CONTENTS

Table of Contents ........................................................................................................................................... i Appendices .................................................................................................................................................... i Table of Tables ............................................................................................................................................. ii Table of Figures ............................................................................................................................................ ii 1 Introduction and Purpose ................................................................................................................... 1-1 2 Project Description ............................................................................................................................. 2-1 3 WWTF Flows, Loading and Effluent Limits ........................................................................................ 3-1 4 Solids and Flow Balances .................................................................................................................. 4-1 5 Basic Design Data .............................................................................................................................. 5-1 6 Geotechnical Data Report .................................................................................................................. 6-1 7 Civil Design Summary ........................................................................................................................ 7-1 8 Architectural Preliminary Design Summary ....................................................................................... 8-1 9 Structural Preliminary Design Summary ............................................................................................ 9-1 10 Mechanical Process Design Summary ......................................................................................... 10-1 11 Mechanical - Kruger BAF Design Summary .................................................................................... 11-1 12 Mechanical Chemical Feed Process Design Summary ................................................................ 12-1 13 Mechanical Odor Control Summary .............................................................................................. 13-1 14 Mechanical HVAC Design Summary ............................................................................................ 14-1 15 Mechanical Plumbing Design Summary ....................................................................................... 15-1 16 Mechanical Fire Protection Design Summary ............................................................................... 16-1 17 Electrical Preliminary Design Summary ........................................................................................... 17-1 18 Instrumentation and Control Preliminary Design Summary ............................................................. 18-1 19 Construction Sequencing ................................................................................................................. 19-1 20 Construction Staging and Safety ..................................................................................................... 20-1 21 Projected Construction Drawing List ................................................................................................ 21-1 22 Projected Construction Specification List ......................................................................................... 22-1 23 Nomenclature List ............................................................................................................................ 23-1 24 Permitting Summary ......................................................................................................................... 24-1 25 Preliminary Opinion of Cost ............................................................................................................. 25-1 26 Preliminary Drawings ....................................................................................................................... 26-1

APPENDICES

Appendix A Design Phase 1 Summary Memorandum Table of Contents Appendix B Summary of Proposed Stormwater Best Management Practices Appendix C Hazardous Materials Memorandum Appendix D Computational Fluid Dynamics Analysis Appendix E Revised Permitting Needs Assessment Appendix F Shoreland Tree Inventory Report Appendix G Marsh Elder Survey Report Appendix H NHDHR Letter of Acceptance

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TABLE OF TABLES

Table 1-1. Current Consent Decree Peirce Island WWTF Milestones and Dates ..................................... 1-3 Table 1-2. Proposed Consent Decree Modification Peirce Island WWTF Milestones and Dates ............. 1-4 Table 3-1. Existing Condition Flow Rates to Secondary Treatment .......................................................... 3-1 Table 3-2. Secondary Treatment Process Design Flow Rates .................................................................. 3-2 Table 3-3. WWTF Influent Maximum Design Flow Rates .......................................................................... 3-2 Table 3-4. Projected Year 2032 Design Flows and Loads to Secondary .................................................. 3-3 Table 3-5. Design Effluent Limits ............................................................................................................... 3-3 Table 9-1. Design Live Loads .................................................................................................................... 9-5 Table 9-2. Impact Loads ............................................................................................................................ 9-6 Table 12-1. Typical IO Points ................................................................................................................... 12-4 Table 13-1. Estimates of Air Flow Rates from Odor Sources at Peirce Island WWTF ............................ 13-1 Table 13-2. Odor Sources for Odor Control System No. 1 ...................................................................... 13-2 Table 13-3. Odor Control System No. 1 - Biofilter Preliminary Design Criteria ....................................... 13-3 Table 13-4. Odor Sources for Odor Control System No. 2 ...................................................................... 13-3 Table 13-5. Odor Control System No. 2 Dual Media Adsorber Preliminary Design Criteria ................ 13-4 Table 18-1. PLC Locations....................................................................................................................... 18-1 Table 21-1. Area Designations ................................................................................................................ 21-1 Table 21-2. Discipline Abbreviations ........................................................................................................ 21-1 Table 21-3. Projected Construction Drawing List .................................................................................... 21-1 Table 22-1. Projected Construction Specification List ............................................................................. 22-1 Table 23-1. Building and Room Nomenclature ........................................................................................ 23-1 Table 23-2. System Nomenclature .......................................................................................................... 23-4 Table 24-1. Summary of Permitting Requirements .................................................................................. 24-2 Table 25-1. Preliminary Opinion of Capital Cost ...................................................................................... 25-2

TABLE OF FIGURES

Figure 9-1. Pressure on Foundation Wall Due to a Surface Line Load ..................................................... 9-7 Figure 9-2. Pressure on Foundation Wall Due to a Surface Point Load .................................................... 9-7 Figure 10-1. Bar Screen and Wash Press ............................................................................................... 10-2 Figure 10-2. Grit Pump Examples ............................................................................................................ 10-3 Figure 10-3. Aerzen Delta Blower Generation 5 ...................................................................................... 10-3 Figure 10-4. Examples of Plunger Pumps ............................................................................................... 10-4 Figure 10-5. Thern Portable Davit Crane (left) and ABS XFP Submersible Pump (right) ....................... 10-6 Figure 10-6. Aerzen Hybrid Blower with Twisted Rotor ........................................................................... 10-6 Figure 10-7. ABS Dry Pit Submersible Pumps (left) and Valmatic SurgeBuster Check Valve (right) ..... 10-8 Figure 10-8. Brger Rotary Lobe Pump ................................................................................................... 10-9 Figure 10-9. Vaughan Horizontal Chopper Pump .................................................................................... 10-9 Figure 10-10. Huber Screw Press .......................................................................................................... 10-11 Figure 10-11. Compressors (from right to left) Sullair, Atlas-Copco, Kaeser ........................................ 10-11 Figure 10-12. Grundfos BoosterpaQ Skid (left) S.P. Kinney Automatic Strainer (right) ........................ 10-12 Figure 12-1. Watson Marlow 520 and 620 Tubing Pumps ...................................................................... 12-4 Figure 13-1. Example Biofilter Media ....................................................................................................... 13-2 Figure 18-1. Simplistic View of Process Control ...................................................................................... 18-2 Figure 18-2. Feedback Control Block Diagram ........................................................................................ 18-3 Figure 18-3. Control System Diagram ..................................................................................................... 18-3

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1 INTRODUCTION AND PURPOSE

1.1 Project Background

The City of Portsmouth has been issued a Consent Decree by the US Environmental Protection Agency (EPA) to upgrade the existing Peirce Island Wastewater Treatment Facility (WWTF) to provide secondary treatment. In response to the requirements of the Consent Decree, the City completed a Draft Wastewater Master Plan and Long Term Control Plan Update (WWMP/LTCP Update). The Draft WWMP/LTCP Update was developed to address the requirements of the Consent Decree while also taking into consideration the long term needs of the Citys wastewater collection and treatment system.

The City presented its Final Wastewater Master Plan in November, 2010. The compliance strategy was focused on upgrading the existing WWTF to include secondary treatment and stay within the existing fence line. This was planned to be accomplished by reusing the existing Filter Building at the Peirce Island WWTF to achieve secondary treatment in accordance with the National Pollutant Discharge Elimination System (NPDES) permit issued in 2007. The compliance strategy was based on using high rate, small footprint treatment technologies to provide secondary treatment. The Final Wastewater Master Plan Submission recommended that the technologies be piloted to determine the most applicable technology for use in upgrading the Peirce Island WWTF in the compliance strategy. It was also recommended that due to a lack of data on existing wastewater characteristics, a wastewater characterization program be completed during the piloting effort. The piloting program was then undertaken in phases.

1.1.1 WWMP Piloting Phase 1 Engineering Evaluation

In the Phase 1 Engineering Evaluation, potential high rate technologies were identified, developed, and compared to select the most promising technologies for piloting in Phase 2, the Initial Piloting Phase. As part of the Phase 1 Engineering Evaluation, existing flow and loading data for the Peirce Island WWTF were reviewed to identify projected dry weather flows and loadings for the proposed secondary treatment processes. The projected flows and loadings were used in developing conceptual planning level unit process sizes and estimated capital, operating, and maintenance costs for each technology for comparison.

The eight technologies considered included:

Biological Aerated Filter (BAF) Sequencing Batch Reactor (SBR) with BioMag Conventional Activated Sludge (CAS) with BioMag Moving Bed Bioreactor (MBBR) & ActiFlo Moving Bed Bioreactor (MBBR) & CoMag Moving Bed Bioreactor (MBBR) & DAF Membrane Bioreactor (MBR) Conventional Activated Sludge (CAS)

Each technology was evaluated to review its ability to achieve different treatment levels including conventional secondary treatment (monthly average BOD5 and TSS of less than 30 mg/L) and nitrogen removal to monthly average concentrations of 8, 5 and 3 mg/L. Each technology was objectively compared to one another using a weighted evaluation matrix to rank the technologies. Based on this

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review, piloting was conducted for BAF (Option 1), CAS with BioMag (Option 3), and MBBR and DAF (Option 6) in the Phase 2 Initial Piloting effort. The results of this evaluation were summarized in the Task 1.7 Technology Evaluation Final Technical Memorandum dated September 26, 2011, hereinafter referred to as the Phase 1 Evaluation.

1.1.2 WWMP Piloting Phase 2 Initial Piloting

The primary focus of the Phase 2 Initial Piloting was to evaluate the ability of the three technologies to meet the secondary treatment effluent limits as defined in the NPDES permit issued to the City by EPA in 2007. The pilot protocol was later revised to evaluate the ability of the three processes to meet effluent nitrogen levels of 8 mg/l and 3 mg/l. Other goals of the piloting effort included:

Complete a wastewater characterization program to define the loadings to be treated at the upgraded WWTF.

Establish the design flows for the upgraded WWTF. Confirm Manufacturer/Vendor sizing criteria and space requirements to provide secondary

treatment/nitrogen removal using each technology. Define technology performance under varying flow conditions. Identify operational and maintenance factors specific to each technology.

In accordance with the Citys Consent Decree, a Piloting Technical Memorandum was submitted on September 28, 2012. This memorandum showed that all three of the technologies were capable of consistently achieving 8 mg/L and inconsistently achieving 3 mg/L total nitrogen in the effluent. The memorandum included a life cycle cost summary which showed that the BAF technology had the lowest life cycle cost of the three piloted technologies. Additionally, the BAF was shown to have the highest value ratio based on an evaluation of qualitative factors important to the long-term operation and maintenance of the facility. AECOM recommended the BAF technology for implementation at the Peirce Island WWTF based on these findings. Further development of the concept showed that it was able to fit within the WWTF existing fence line. On April 8, 2013, the City Council voted to move forward with the design of a two-stage BAF system capable of achieving 8 mg/L on a seasonal rolling average basis and construct all of the necessary upgrades within the existing fence line.

1.1.3 Design Phase 1

Design Phase 1 advanced the design of the necessary upgrades to approximately the 10% completion level. Major facets of this phase of the design included:

Site investigations Preliminary permitting Advancement of the process and hydraulic design Evaluation of the existing facilities Development of construction constraints, and Review of potential sustainable features

The Design Phase 1 Summary Memorandum dated March 2014 summarized the results of the Design Phase 1 efforts and provided a comprehensive summary of the scope of the plant upgrade project. The Table of Contents for the Design Phase 1 Summary Memorandum is included in Appendix A. Copies of the Design Phase 1 Summary Memorandum were submitted to NHDES and EPA.

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1.2 Purpose

The purpose of Design Phase 2 is to advance the design of the WWTF Upgrade from the 10% completion level to approximately the 30% completion level. Major facets of this phase of the design include:

Advancement of process design calculations Development of discipline specific design criteria Preliminary equipment selection Preparation of preliminary civil, architectural, mechanical, instrumentation and electrical drawings Preparation of a preliminary drawing list and specification list Preliminary permitting update Update of opinion of cost for the construction of the project

This 30% Final Design Report dated July 2014 summarizes the results of the Design Phase 2 efforts and provides definition of the elements of the upgrade design. The 30% Final Design Report is to provide a document suitable for review and use by the Citys Value Engineering team. In order to meet the Consent Decree schedule, the final design effort will continue to proceed while the Citys Value Engineering team reviews the 30% Final Design Report.

1.3 Consent Decree Requirements

The Consent Decree between the City and EPA was executed in August 2009 and modified in July 2012 and contained milestones and dates for the completion of the Draft and Final WWMP/LTCP Updates. The City has met the required milestone dates contained in the original Consent Decree. During the course of the piloting evaluation, EPA and the City negotiated a modification to the Consent Decree which contains further milestones and dates for implementation of both the CSO Long Term Control Plan projects and the upgrade of the Peirce Island WWTF to secondary treatment. The relevant milestones and dates for the Peirce Island WWTF upgrade are presented in Table 1-1 and reflect the modified Consent Decree from July 2012.

Table 1-1. Current Consent Decree Peirce Island WWTF Milestones and Dates

Milestone Action Date The City shall complete pilot testing of potential treatment technologies for achieving secondary treatment, including, but not necessarily limited to: Biologically Aerated Filters (BAF), BioMag, Moving Bed Biofilm Reactors (MBBR) w/ Dissolved Air Flotation (DAF), and Conventional Activated Sludge with BioMag.

June 30, 2012

The City shall complete a data summary relative to the pilot testing. July 30, 2012 The City shall submit a Piloting Technical Memorandum that includes data from piloting and a recommendation on the design and capacity of secondary treatment facilities.

October 1, 2012

The City shall commence final design of secondary treatment facilities. July 1, 2013 The City shall complete design of secondary treatment facilities. August 31, 2014 The City shall commence construction of secondary treatment facilities. March 1, 2015 The City shall complete construction of secondary treatment facilities. March 1, 2017 The City shall achieve compliance with secondary treatment limits in the Permit. May 1, 2017

With the initiation of work on Design Phase 1 in June 2013, the City commenced design of secondary treatment facilities in advance of the Consent Decree date. As shown in Table 1-1, the above schedule

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was negotiated based on an upgrade for secondary treatment. However, the upgrade under design includes facilities capable of removing nitrogen. The additional facilities necessary for nitrogen removal substantially increase the scope and cost of the project to the point that extraordinary measures would be necessary on the part of the City, the design engineer, and the construction contractor to meet the current Consent Decree schedule. As such, the City has requested a modification to the above schedule which would extend the overall schedule by a total of 18 months in order to incorporate the nitrogen removal treatment facilities. The proposed schedule is shown below in Table 1-2. The City and AECOM are currently working towards the schedule in Table 1-2.

Table 1-2. Proposed Consent Decree Modification Peirce Island WWTF Milestones and Dates

Milestone Action Date The City shall complete design of nitrogen removal treatment facilities. March 1, 2015 The City shall commence construction of nitrogen removal treatment facilities. September 1, 2015 The City shall complete construction of nitrogen removal treatment facilities. June 1, 2018 The City shall achieve compliance with nitrogen removal treatment limits in the Permit.

November 1, 2018

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2 PROJECT DESCRIPTION

The oldest portions of the Peirce Island WWTF were constructed around 1965 and consisted of primary treatment and disinfection. The plant was upgraded around 1990 with an aerated grit system, new primary clarifiers, a primary effluent sand filter system (that is currently out of service), an Administration Building, and sludge thickening, storage and dewatering. The plant was upgraded again around 2005 to provide chemically enhanced primary treatment (CEPT) with ferric chloride and polymer storage and feed systems and other miscellaneous improvements.

The current treatment process consists of aerated grit chambers, chemically enhanced primary settling, and chlorination/dechlorination. Sludge is thickened in a gravity thickener and then temporarily stored in aerated sludge storage tanks before being dewatered by belt filter presses.

This project consists of an upgrade of the WWTF to allow for the operation of the WWTF for the next 20 years and to provide nitrogen removal. A significant portion of the project is to upgrade existing equipment, systems, and facilities. Major WWTF additions include a new headworks, a new gravity thickener, replacement of the existing Administration Building with a new Solids Building, a new two-stage Biological Aerated Filter (BAF) system, and replacement of the existing Solids Processing Building with a new Operations/Lab Building. The upgrades for the WWTF will be constructed through two separate contracts. The first contract will include the replacement of the primary clarifier equipment, replacement of Gravity Thickener No. 1 equipment, and modifications to the Primary Clarifier Influent Distribution Box. Construction for the first contract is planned to be substantially completed by fall of 2015. The second contract will include a new headworks, Gravity Thickener No. 2, new Solids Building, new Operations/Lab Building, equipment replacement and the BAF system. Construction for the second contract is planned to be completed by June 1, 2018.

The plant treats wastewater from a combined sewer system, resulting in a large variation between average and peak flows. The peak design flow is 22.0 mgd. The design flow for the BAF system with all cells operating is 6.13 MGD average and 10.33 MGD peak (not including recycle flows). At times of high wet weather flow, all of the flow will undergo CEPT. A portion of this wet weather flow will bypass the BAF system and flow directly to disinfection. Section 3 provides further discussion of design flows and loads.

The following sections describe the upgrades proposed throughout the WWTF.

2.1 Liquid Process

2.1.1 Headworks Building

The design will include a new influent screening system to be installed in the new Headworks Building. Flow from the Mechanic Street Pump Station and flow from the Town of New Castle will join together ahead of the influent screens. The flow from New Castle is conveyed from the existing River Road Pump Station through an existing force main that will be extended to the new Headworks Building. The force main from the River Road Pump Station will be provided with a new flow meter. Flow from the Mechanic Street Pump Station will be measured with the existing flow meter located within the existing pump station.

Two mechanically cleaned bar screens with 6 mm spacing will be provided, each capable of passing 11.0 MGD. Each screen will discharge collected screenings into a dedicated wash press. The wash presses will clean and dewater the screenings to remove organic material and to minimize odors. The wash

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presses will discharge washed screenings into a container, located at grade level, for off-site disposal. As a back up to the screen a manually cleaned bar rack will be installed in a third channel. The wash presses will be connected to the plant water system for wash water supply. The current layout for the Headworks is based on Mahr bar screens.

The wastewater channels will be covered and connected to a new biofilter for odor control. A new influent automatic sampler will be provided with the sample point located upstream of the influent screens.

2.1.2 Aerated Grit Chamber Rehabilitation

The project will include the reuse of the existing Aerated Grit Chambers. Modifications for the aerated grit chambers include replacement of the existing aeration piping, diffusers, blowers, grit pumps and piping. Additionally, the influent and baffling arrangement within the Aerated Grit Chambers will be modified to improve performance.

The grit pumps will be replaced with three variable speed, recessed impeller pumps. The grit piping will be provided with connections to the plant water system for flushing and will include air taps for cleaning and long radius bends. A portable air compressor will be used for cleaning of grit piping.

All three existing blowers for the aerated grit chambers and Sludge Storage Tank No. 3 and 4 will be replaced with three variable speed, rotary lobe blowers.

The existing grit screw conveyors have been removed from the grit hopper in each grit chamber. A new, chain-driven screw conveyor will be provided at the same location as the previous conveyor for each chamber. The slide gates associated with the aerated grit chamber at the influent, effluent and bypass channels will be replaced due to their deteriorated condition.

In addition to the mechanical equipment replacement, the weirs in the grit chamber will be replaced, new baffles will be installed, and the flow pattern within the grit chamber altered so that influent enters on the opposite side of the tank to improve the air-induced spiral roll. The flow pattern and baffle design for the aerated grit chambers are based on a Computational Fluid Dynamics (CFD) analysis. The grit chambers will be covered with an aluminum cover, and exhaust air from the headspace above the grit chambers will be conveyed to a biofilter for odor control.

The existing grit classifier will be replaced. The new grit classifier will be provided with two cyclone grit separators. The new grit classifier will be provided with an overflow basin and level sensor, similar to the existing classifier. The Grit Classifier Room will be connected to the biofilter for odor control.

2.1.3 Primary Clarifier and Distribution Box Rehabilitation

2.1.3.1 Primary Clarifiers and Influent Distribution Box

The equipment replacement and upgrades at the primary clarifiers and influent distribution box will be completed in a separate contract. The connection of the primary clarifiers and influent distribution box to the biofilter for odor control will be included with this contract. Sludge blanket level sensors will also be included as part of the WWTF Upgrade.

2.1.3.2 Primary Clarifier Effluent Distribution Box

The project includes rehabilitation of the Primary Clarifier Effluent Distribution Box.

Upgrades to the Primary Clarifier Effluent Distribution Box include:

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Structural repairs based on inspections during construction Addition of an inverted gate for CEPT flow Aluminum plate cover to allow for odor control

2.1.3.3 Pumps & Other Mechanical Equipment

The design includes the removal and replacement of existing primary sludge pumps and primary scum pumps. The three existing primary sludge pumps will be replaced with three, variable speed, rotary lobe pumps. Two grinders will be provided on the primary sludge suction piping. The primary sludge pumps will have the capability to pump to Gravity Thickener No. 1 and Gravity Thickener No. 2. The primary sludge pumps will also have the capability to pump to the Primary Clarifier Influent Box for draining the primary clarifiers. The suction piping for the primary sludge pumps will be provided with a cross connection to the screw press feed pump suction piping to allow for dewatering of primary sludge.

The three existing primary scum pumps will be replaced with two, variable speed, recessed impeller type pumps. The primary scum pumps will have the capability to pump to the grit chambers and Sludge Storage Tank No. 1 and 2. These pumps will also have the capability of pumping down the scum well at Gravity Thickener No.2.

2.1.4 Secondary Treatment Process

2.1.4.1 Secondary Influent Pump Station

A new Secondary Influent Pump Station will be located in the new Solids Building. The design of the Secondary Influent Pump Station will include two wet wells and four dry-pit submersible solids handling pumps with variable speed drives. The secondary influent pump discharge piping will be designed to provide space for automatic strainers on the discharge of each pump if further solids removal is needed in the future. Hatches and monorails will be provided for equipment maintenance purposes. A new automatic sampler will be provided to take samples of primary effluent from the wet well.

2.1.4.2 Stage 1 BAF

The Stage 1 BAF system includes a 6-cell Kruger BAF system designed for carbon oxidation and nitrification. The Stage 1 BAF will be an upflow filter, where flow will enter the cell at the bottom and flow upward through the filter media. The filter media is a polystyrene material and will be retained by the nozzle slab located at the top of each cell. Air diffusers are located below the media bed to provide air to the entire filter bed. Influent flow to the BAF cells will be controlled with flow meters and modulating butterfly valves. Effluent will flow to the Nitrified Effluent Channel, located above the Denitrified Effluent Channel. Backwash for the Stage 1 BAF cells will flow by gravity from the Nitrified Effluent Channel, downward through the BAF cell and discharge to the Stage 1 Mudwell. Three mudwell pumps will be provided for the Stage 1 Mudwell. The mudwell pumps will be variable speed, submersible pumps and will pump backwash water to the Primary Clarifier Influent Distribution Box or to Gravity Thickener No.2.

Kruger has been preselected as the sole source vendor of the Stage 1 BAF system and has provided design information and recommendations for the BAF Facility. Kruger will supply equipment internal to the BAF cells, blowers, compressors, mudwell pumps, control valves and the control system. A full list of Krugers scope of supply and other design information provided can be found in Section 11.

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2.1.4.3 Stage 2 BAF

The Stage 2 BAF system includes a 6-cell Kruger BAF system designed for denitrification. The Stage 2 BAF will be an upflow filter, where flow will enter the cell at bottom and flow upward through the filter media. The filter media is a polystyrene material and will be retained by the nozzle slab located at the top of each cell. Air diffusers are located below the media bed to provide air scouring during backwash. Stage 2 BAF influent flow will flow by gravity from the Nitrified Effluent Channel into a single header. Influent flow from the nitrified effluent header to the Stage 2 BAF will be controlled with flow meters and modulating butterfly valves at each cell. Micro C will be used for a carbon source and will be injected into the nitrified effluent header before flow is split to each cell. The Micro C will be mixed with a pump diffusion flash mix system located in the nitrified effluent header. Denitrified effluent will flow from each cell to the Denitrified Effluent Channel and then to the Effluent Distribution Box located near the Chlorine Contact Tanks. A flow meter will be provided on the denitrified effluent pipe, within the Gallery of the BAF Facility. Within the Gallery of the BAF Facility the denitrified effluent pipe will include an oversized section of pipe to reduce flow velocity to allow for removal of entrained air from the denitrified effluent. The oversized section of pipe will include a vent pipe that will discharge into the Denitrified Effluent Channel. Sodium hypochlorite will be injected into the denitrified effluent pipe at the BAF Facility.

Backwash for the Stage 2 BAF cells will flow by gravity from the Denitrified Effluent Channel, downward through the BAF cell and discharge to the Stage 2 Mudwell. Three mudwell pumps will be provided for the Stage 2 Mudwell. The mudwell pumps will be variable speed, submersible pumps and will pump backwash water to the Primary Clarifier Influent Distribution Box or to Gravity Thickener No.2.

Kruger has been preselected as the sole source vendor of the Stage 2 BAF system and has provided design information and recommendations for the BAF Facility. Kruger will supply equipment internal to the BAF cells, blowers, compressors, mudwell pumps, control valves and the control system. A full list of Krugers scope of supply and other design information provided can be found in Section 11.

2.1.5 Disinfection System Rehabilitation

The existing Chlorine Contact Tanks and Dechlorination Structure will be reused. Sodium hypochlorite will be injected into the denitrified effluent at the BAF facility. During wet weather, when the daily forward flow exceeds 9.06 MGD, sodium hypochlorite will also be injected at the Primary Clarifier Effluent Distribution Box, downstream of the wet weather weir. Sodium bisulfite will be injected at the existing Dechlorination Structure. A chlorine analyzer will be provided near the beginning of each chlorine contact tank and the measured chlorine residual used to trim the sodium hypochlorite dose. An Oxidation-Reduction Potential (ORP) analyzer and auto sampler will be provided at the effluent chamber after the Dechlorination Structure and the measured ORP used to trim the sodium bisulfite dose. The existing scum collection system located in the Chlorine Contact Tanks will remain. The existing Chlorine Contact Tanks have cracking and spalling in the walkways and slabs, which will be repaired. The common wall shared with the existing Solids Processing Building and associated slab and beams will be replaced when the existing Solids Processing Building is demolished.

2.1.6 Effluent Meter Structure Rehabilitation

The existing Effluent Meter Structure is currently used only for flow distribution between the two chlorine contact tanks. The existing parshall flume at the Effluent Meter Structure is not in operation. The existing Effluent Meter Structure will be modified to become the Effluent Distribution Box and will be used to combine secondary effluent and wet weather secondary bypass flow and distribute the combined plant flow between the two Chlorine Contact Tanks.

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Upgrades to the existing Effluent Meter Structure include:

Demolition of the Parshall Flume and construction of new wall Replacement of slide gates New slide gate at discharge of denitrified effluent pipe Miscellaneous concrete repairs

2.2 Solids Handling

2.2.1 Sludge Thickening

2.2.1.1 Gravity Thickener No.1 Rehabilitation

The equipment replacement and upgrades at Gravity Thickener No. 1 will be completed in a separate contract. The connection of Gravity Thickener No. 1 to the biofilter for odor control will be included with this contract.

2.2.1.2 Gravity Thickener No. 2

Gravity Thickener No. 2 will be 40-feet in diameter and will be covered with a dome cover. The air space will be exhausted to the odor control system. The gravity thickener equipment will be designed to be similar to equipment for Gravity Thickener No. 1. Two new thickened sludge pumps will be provided for Gravity Thickener No. 2. These pumps will be variable speed plunger pumps and will be located in the new Solids Building. Flow to Gravity Thickener No. 2 will be measured with a magnetic flow meter. Dilution water will be provided at the gravity thickeners to provide a consistent hydraulic loading rate. Dilution water for the gravity thickeners will be supplied from the plant water system. Gravity Thickener No. 2 will be elevated and will be provided with an exterior perimeter walkway.

2.2.1.3 Thickened Sludge Pumping

The three existing thickened sludge pumps, located in the Grit Building, will be replaced with two new variable speed plunger pumps, located in the same area as the existing pumps. The thickened sludge pumps have the flexibility to pump from Gravity Thickener No. 1 and Sludge Storage Tank No. 3 and 4 to Sludge Storage Tank No. 1 through 4. Existing valves in the thickened sludge piping will be replaced. The thickened sludge piping will be provided with plant water connections for flushing.

The project will include two new thickened sludge pumps located in the new Solids Building. These pumps will be variable speed plunger pumps and will have the flexibility to pump from Gravity Thickener No. 2 and Sludge Storage Tank No. 1 and 2 to Sludge Storage Tank No. 1 through 4. The thickened sludge piping will be provided with plant water connections for flushing.

2.2.2 Sludge Storage

Thickened sludge from the gravity thickeners will be pumped to aerated sludge storage tanks.

2.2.2.1 Sludge Storage Tank Rehabilitation

The existing facility has four sludge storage tanks. Sludge Storage Tank No. 1 and 2 are located adjacent to the existing Administration Building and Sludge Storage Tank No. 3 and 4 are located adjacent to the Grit Building. The project includes rehabilitation of Sludge Storage Tank No. 3 and 4. The rehabilitation of

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the existing sludge storage tanks includes new aeration piping and coarse bubble diffusers, connection to new odor control system, new protective coating, structural repairs as necessary and new level instrumentation.

Sludge Storage Tank No. 1 and 2 will be demolished with the demolition of the existing Administration Building and will be replaced with two new sludge storage tanks as part of the new Solids Building. The new tanks will be covered, connected to the odor control system and aerated with coarse bubble diffusers. The tanks will be provided with access hatches for maintenance purposes. The new tanks will be sized to provide three days of storage during max day sludge production conditions.

2.2.2.2 Blowers

The project will include replacement of the two existing sludge storage tank blowers in the existing Administration Building. Three variable speed rotary lobe blowers will be provided to serve Sludge Storage Tank No. 1 and 2 and will be located in the lower level of the new Solids Building.

2.2.3 Sludge Dewatering

Sludge will be dewatered via new rotary screw presses located in the new Solids Building. Dewatered sludge will be conveyed and distributed to new containers or trailers in two truck bays.

2.2.3.1 Screw Presses

Three screw presses will have the capacity to dewater the maximum week sludge production in 40 hours or less with all units operating. The screw presses will be located in the new Solids Building. Pressate from the screw presses will be directed to the Stage 2 Mudwell. Alternatively, the pressate could be directed to the Secondary Influent Pump Station Wet Well. Each screw press will connected to Odor Control System No. 2. The screw presses will require the following items which will be included in the design:

Polymer storage and feed systems A permanganate feed system Piping and carrier water systems Removal method for screws for maintenance Polymer injection rings Air compressors

2.2.3.2 Pumps & Other Mechanical Equipment

The three existing belt filter press feed pumps will be replaced with four screw press feed pumps, located in the lower level of the Solids Building. The screw press feed pumps will be variable speed rotary lobe pumps. In-line grinders will be provided on the screw press feed pump suction piping. Each screw press will have a dedicated feed pump and flow meter. The suction piping for the screw press feed pumps will be provided with a cross connection to the primary sludge pump suction piping to allow for dewatering of primary sludge. The suction piping for the screw press feed pumps will also be cross connected with the thickened sludge piping from Gravity Thickener No. 2. Thickened sludge piping associated with the screw press feed pumps will be provided with connections to the plant water system.

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2.2.3.3 Conveyors

Three shaftless screw conveyors will be provided to convey sludge from the screw presses to either containers or trailers in two truck bays. The two conveyors in the truck bays will have multiple discharge points to evenly distribute dewatered solids into containers or trailers and will be reversible. Discharge points will be isolated with pneumatically actuated gates, which will provide the plant staff with the ability to control where sludge is discharged to. The sludge conveyors will be covered and connected to the odor control system and connections to plant water for flushing will be provided.

2.3 Ancillary Systems and Facilities

A number of WWTF ancillary facilities upgrades are to be provided. These facilities include the following:

Ferric Chloride Storage & Feed System Polymer Systems Sodium Hypochlorite Feed System Sodium Bisulfite Feed System Micro-C Storage & Feed System Pump Diffusion Flash Mix System Caustic Soda Storage & Feed System Potassium Permanganate Storage & Feed System Odor Control Flow Meter Vaults Control, Instrumentation, and Communication Systems Compressed Air Systems HVAC Upgrades Electrical Systems Main Switchgear Emergency Generator Plant Water System Plant Drain System Fuel Oil Systems Buildings and Architectural Components

o New Headworks Building o Reconfiguration of the Grit Building o New Stage 1 and Stage 2 BAF Facility o New Solids Building o New Operations/Lab Building

Plant Security Demolition

These systems are described below.

2.3.1 Ferric Chloride Storage & Feed System

A ferric chloride storage and feed system will be provided for coagulation. The existing ferric chloride bulk storage tanks will be replaced with two new ferric chloride tanks. The new tanks will have the same capacity as the existing tanks and will be located in the same area. New metering pumps and a day tank will be located in a new Ferric Chloride Room in the lower level of the Grit Building. Two sets of ferric chloride metering pumps will be provided. One set of metering pumps will be sized for CEPT flow and the

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second set will be sized for backwash coagulation. New transfer pumps will be provided to transfer ferric chloride from the bulk storage tanks to the new day tank. The transfer pumps will be located in a heated enclosure in the ferric chloride storage area, similar to the existing system. The ferric chloride metering pumps will be peristaltic pumps.

2.3.2 Polymer Systems

Two polymer storage and feed systems will be provided. The system located in the Grit Building is for flocculation for CEPT flow and backwash. The system located in the Solids Building is for dewatering. These systems will consist of the following:

Polymer blend units designed for emulsion polymers Polymer tote storage Secondary containment Dilution water and piping

The polymer system in the Grit Building will be located in a dedicated room and will include four polymer blend units and storage area for two polymer totes. The totes will be located on an elevated platform and handled with a forklift. The elevated platform and polymer blend units will be located within a secondary containment curb. The polymer system will be designed to dose the entire plant flow as well as the periodic backwash flow.

The polymer system in the Solids Building will be located in in the Truck Bay and will include four polymer blend units and storage area for six polymer totes. The Polymer Area will be designed with a depressed floor and grating to provide secondary containment as well as easy access for tote removal and replacement. Each polymer blend unit will have the capacity to dose polymer for a dedicated screw press. One standby polymer blend unit will be provided for dewatering.

2.3.3 Sodium Hypochlorite Storage & Feed System

A sodium hypochlorite feed system will be provided for disinfection of final effluent. This system will include the following:

A set of metering pumps for denitrified effluent flow A set of metering pumps for wet weather secondary bypass flow Carrier water and piping Secondary containment

The sodium hypochlorite storage and feed system will reuse the existing sodium hypochlorite storage bulk tanks located in the existing Chemical Storage Building. The new sodium hypochlorite feed system will be located in the lower level of the new Operations/Lab Building within a secondary containment curb. Sodium hypochlorite will be injected into the denitrified effluent pipe at the BAF Facility for disinfection of denitrified effluent. Sodium hypochlorite will be injected at the Primary Clarifier Effluent Distribution Box, downstream of the wet weather weir for disinfection of secondary bypass flow. Sodium hypochlorite will also be injected into the plant water system to minimize biological growth throughout the plant water system. Additional disinfection of the plant water system will be periodic and one of the spare sodium hypochlorite metering pumps will be used to dose this injection point. Due to the wide range of dosing requirements for each injection point, a dedicated set of metering pumps will be provided for each injection point. The sodium hypochlorite metering pumps will be peristaltic pumps.

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2.3.4 Sodium Bisulfite Storage & Feed System

A sodium bisulfite feed system will be provided for dechlorination of final effluent. This system will include the following:

Metering pumps New sodium bisulfite bulk storage tank Carrier water and piping Secondary containment

The new sodium bisulfite storage and feed system will include the replacement of the existing sodium bisulfite tank located in the existing Chemical Storage Building. The new sodium bisulfite feed system will be located in the lower level of the new Operations/Lab Building within a secondary containment curb. Sodium bisulfite will be injected at the existing Dechlorination Structure. The sodium bisulfite metering pumps will be peristaltic pumps.

2.3.5 Micro-C Storage & Feed System

A Micro-C storage and feed system will be provided for carbon addition into the nitrified effluent header. This system will include the following:

Two bulk storage tanks Metering pumps Carrier water and piping Secondary containment

The Micro-C system will be located in the BAF Facility in a dedicated room. Micro-C will be injected into the nitrified effluent header before flow is split to the Stage 2 BAF cells. Micro-C will be mixed within the nitrified effluent header with a pump diffusion flash mix system. The Micro-C metering pumps will be peristaltic pumps.

2.3.6 Caustic Soda Storage & Feed System

A Caustic Soda storage and feed system will be provided for alkalinity addition. This system will include the following:

Two storage tanks Metering pumps Carrier water and piping Secondary containment

The caustic soda storage and feed system will be located in a dedicated room in the new Solids Building. Caustic soda will be injected into the wet wells at the Secondary Influent Pump Station. The caustic soda metering pumps will be peristaltic pumps.

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2.3.7 Potassium Permanganate Storage & Feed System

A potassium permanganate storage and feed system will be provided for dewatering and sludge storage odor control. This system will include the following:

Metering pumps Dry potassium permanganate eductor system Mixing tank and mixer Drum storage area Water supply and piping

The potassium permanganate storage and feed system will be located in a dedicated room in the new Solids Building. The room will be provided with an area to store three drums of dry potassium permanganate. The dry potassium permanganate eductor system will be provided to transfer dry product from the drums to the mixing tank. Each metering pump will have the capacity to dose potassium permanganate for a dedicated screw press as well as the sludge storage tanks. The potassium permanganate metering pumps will be peristaltic pumps. The existing potassium permanganate piping to Sludge Storage Tank No. 3 and 4 will be reused as applicable. The Potassium Permanganate Room will be provided with secondary containment.

2.3.8 Odor Control

A new distributed odor control system and odor control fans will be provided. Exhaust air from the following areas will be conveyed to the odor control system:

Headworks - Screen Channels, Screens and Wash Presses Headworks - Screenings Dumpster Area Grit Classifier Room Grit Chambers and Channels Primary Clarifier Distribution Boxes Primary Clarifier Launders Secondary Influent Pump Station Wet Well Sludge Storage Tank No. 1 through 4 Gravity Thickener No. 1 and 2 Screw Presses and Conveyors Dewatered Sludge Truck Bays

The new odor control system will be distributed between two odor control systems to treat odorous air from these sources. Odor Control System No. 1 will be a biofilter system and will be located outdoors. Odor Control System No. 1 will treat odors from the Headworks, Grit Building, primary clarifier effluent launders and Gravity Thickener No. 1. The odor control system will be housed in a concrete structure. Inside the concrete structure would be an inlet air humidification system, air distribution plenum, media support system, and the manufactured media. Removable covers will be provided to better control environmental conditions inside the biofilter and allow the air to be discharged through short stacks. The enclosed odor control fan will be located near the odor control system. Odor Control System No. 1 will be located at grade with H-20 rated covers.

Odor Control System No. 2 will be a dry, dual media carbon system and will be located outdoors. Odor Control System No. 2 will treat odors from Gravity Thickener No. 2 and the Solids Building. The system will include a grease/mist eliminator, an enclosed fan, and a 10 ft. diameter, 10 ft. tall radial flow fiberglass

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reinforced plastic (FRP) adsorber vessel housing layers of both activated carbon and permanganate impregnated media. The odor control fan will be located near the odor control system.

2.3.9 Flow Meter Vault

A flow meter vault will be provided for the magnetic flow meter that will measure the primary effluent wet weather flow that bypasses secondary treatment and flows directly to the chlorine contact tanks. The meter will be located on the existing 36-inch primary clarifier effluent pipe, between the Primary Clarifier Effluent Distribution Box and the Effluent Distribution Box. The vault will be a precast structure with access hatches rated for H-20 loading and provided with lighting and drains.

2.3.10 Control, Instrumentation, and Communication Systems

2.3.10.1 Plant Control Systems, Software, and Instrumentation

The existing plant supervisory control and data acquisition (SCADA) system consists of both manual local control and has limited ability to monitor and control plant systems. Many of the control systems and instrumentation components are the original equipment from the 1985 upgrade. The existing plant control system and instrumentation components will be replaced.

The design includes a full upgrade to the plant SCADA system, which includes monitoring and control functions of the major plant systems and equipment. The upgraded SCADA system will be able to monitor and control the Citys remote pump stations that currently report back to the existing SCADA system and will have the ability to be expanded in the future to monitor and control all of the Citys remote pump stations. The new SCADA system will have new software and system configurations including real-time historical reporting software to allow for historical process equipment monitoring as well assist in the generation of required reports for regulatory purposes.

2.3.10.2 Communications System

Internet access will be provided over a new fiber optic link to the BayRing municipal area network (MAN). Copper internet network connections will be provided to the various rooms on the upper level of the Operations/Lab Building only. Connections will also be provided to the various systems requiring internet access such as the CCTV system.

Phone will be provided over the BayRing fiber link. The management of the phone system will be performed by BayRing on their servers. The primary hardware required by the City will be the phones.

A connection to the local cable TV provider will be installed in the duct bank along the access road. The cable TV service will terminate in the Operations/Lab Building. Cable TV drops will be distributed to selected room on the upper level of the Operations/Lab Building.

2.3.10.3 Fire Alarm System

A site wide networked fire alarm system will be provided. It will be an addressable system with remote fire alarm control panels at each building. A fiber optic network will be provided to network the fire alarm panels together. Notification to the fire department will be provided in compliance with the requirements of the fire department. Alarm initiating devices will be provided.

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2.3.11 HVAC Systems

New HVAC systems will be designed for the Headworks, Grit Building, BAF Facility, new Solids Building and new Operations/Lab Building. All of the new buildings will have dedicated mechanical rooms and spaces. Propane will be the fuel source for the heating systems throughout the WWTF. Air conditioning will be provided in electrical rooms as required. Air conditioning will be provided in the Operations/Lab Building as well as the Office in the Solids Building.

PSNH offers a number of rebates for installation of new energy efficient HVAC equipment as well as for upgrading existing equipment with more energy efficient systems. These rebates will be taken into account and equipment coordinated with PSNHs rebate program where possible in order to qualify for the rebates.

2.3.12 Electrical Systems

The project will include the replacement of the plants electrical equipment. New underground duct banks and electrical distribution system will be included with the design. Site lighting will be designed to suit the needs of the new buildings and site layout. A fire alarm system is to be included in the design as well as lightning protection.

The electrical, phone and internet services will enter the site in the area of the main entrance into the WWTF. The new utility transformer will be located off the main road on the site, near the Grit Building. Fiber optic cable will be provided for phone and internet. Using fiber optic cable will allow the facility to connect to the Citys network.

PSNH offers a number of rebates for installation of new energy efficient electrical equipment as well as for upgrading existing equipment with more energy efficient systems. These rebates will be taken into account and equipment coordinated with PSNHs rebate program where possible in order to qualify for the rebates.

2.3.13 Electrical Service

Currently the Public Service New Hampshire (PSNH) power cables enter the WWTF site over water. The existing electrical service is fed from a transformer located on the east side of the site, near the existing Filter Building. Due to maintenance, access, and permitting issues, this method of providing electrical power to the WWTF is no longer feasible and the existing electrical service will be demolished.

The new power cables will interconnect with the existing PSNH network at a new electrical pole in close proximity to the pool and will continue in a duct bank under the access road into the WWTF site and will feed the new utility transformer. The new utility transformer will be located behind the WWTF sign located near the entrance. From the utility transformer the service conductors will be run through a duct bank into the Electrical/Switchgear Room in the Headworks.

2.3.14 Main Switchgear

The existing main switchgear is located in the existing Filter Building. With the demolition of the existing Filter Building and the relocation of the electrical service to the main entrance to the site, a new main switchgear will be provided at the Headworks. The main switchgear will be in the Electrical/Switchgear Room, located near the emergency generator.

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2.3.15 Emergency Power

The existing emergency generator is located in the existing Filter Building. With the demolition of the existing Filter Building and the new main switchgear located in the Headworks, a new emergency generator will be located in the Generator Room in the Headworks. The new generator will be diesel-powered and will have a below ground diesel storage tank located nearby. The new generator will be designed to provide backup power for the entire facility. The emergency generator will be provided with 48 hours of fuel storage at maximum rated power output.

2.3.16 Plant Water System

The project will include a new plant water pumping system with hydropneumatic tank and associated compressors and pumps. The new plant water system will include a distribution system throughout the site to supply all buildings and processes requiring plant water. Existing yard washdown hydrants will be connected to the new plant water system.

2.3.17 Plant Drain System

The existing filtrate pump station, located near the existing Sludge Processing Building, will be demolished. A new pump station will replace the existing pump station at Manhole East. Drainage from the Operations/Lab Building will flow to the new pump station. The new pump station will be provided with duplex submersible pumps which will discharge to the Headworks. A new sanitary pump station will be located near the new Solids Building. The sanitary pump station will be provided with duplex submersible grinder pumps which will discharge to the Headworks.

2.3.18 Heating Fuel Storage

There are two underground fuel oil storage tanks at the WWTF. These existing fuel oil tanks will be removed as well as the existing propane tanks at the existing Solids Building. Where heating fuel is needed, propane will be provided as a source of fuel. Three below ground propane storage tanks will be provided, each with a capacity of approximately 2,000 gallons. These propane storage tanks will be located near the Operations/Lab Building and Chlorine Contact Tanks. The propane tanks will be manifolded together and distribution piping will be routed throughout the site to provide propane where necessary. The existing odor control system and filtrate pump station located in this area will be demolished to provide an area to locate the propane storage tanks.

2.3.19 Buildings and Architectural Components

2.3.19.1 Headworks Building

The design of the upgraded facility includes a new Headworks Building. The Headworks Building will be brick and block construction with a flat roof. The floor elevation in the Screen Room will be raised above grade to accommodate the hydraulic grade line and provide approximately 2 feet of freeboard at peak flow. Stairs and platforms will be provided for access to this room as needed. Floor elevations for all other rooms in the Headworks Building will be at grade. Roll-up doors will be provided for the Wash Bay Garage and the Screenings Garage. Louvers will be provided as required for the emergency generator and HVAC.

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2.3.19.2 Grit Building

The Grit Building will undergo an interior renovation which will include new rooms and separation of chemical and electrical spaces from process areas. This renovation will include interior improvements to meet current building codes including isolation of the grit classifier area, enclosing the existing stairwell and separation of dissimilar environments. Dedicated rooms will be provided for the ferric chloride day tank and metering pumps, polymer system and Electrical Room.

Other upgrades included with the design:

Provide new energy efficient doors windows Weather-stripping at overhead garage door Refinish protective coating in chemical containment areas as needed Cleaning and re-painting of the lower level and grade level including bar joists and underside of

metal roof deck Provide physical separation from the grit classifier area. Provide access for polymer deliveries

2.3.19.3 BAF Facility

The project includes a new building for the BAF Facility and will be constructed at the location of the existing Filter Building. The building includes Stage 1 and Stage 2 BAF cells, Stage 1 and Stage 2 Mudwells, a pipe gallery, a Micro-C storage and feed area, a blower room, a mechanical room, and an electrical/control room. Most of the structure will be concrete tanks faced with brick although portions will be brick and block with a flat roof.

2.3.19.4 Solids Building

A new Solids Building will be constructed in the location of the existing Administration Building. The existing structure of the Administration Building will be demolished. The new building will be provided with doors for truck bay access with sludge containers or trailers. A dedicated room will be provided for caustic soda and potassium permanganate. Access will be provided as needed for handling polymer and potassium permanganate. The building construction will be brick and block with a concrete frame. Exterior concrete will be faced with brick. The roof will be an insulated flat roof and will be pitched for drainage.

The new Solids Building will include the following:

Office Bathroom Electrical room Mechanical room Dewatering room area Secondary influent wet well Secondary influent pump area Aerated sludge storage tanks Pump and blower gallery Two truck bays Potassium permanganate storage and feed area Polymer storage and feed area Caustic soda storage and feed area

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2.3.19.5 Operations/Lab Building

The design includes a new Operations/Lab Building, which will be located in place of the existing Solids Processing Building. The existing Solids Processing Building will be demolished, including the common wall shared with the Chlorine Contact Tanks. A new wall will be constructed for the Chlorine Contact Tanks prior to the demolition of the common wall. The slab on the Chlorine Contact Tanks, near the existing Solids Processing Building, and associated beams will be replaced as part of this construction. The lower level of the Operations/Lab Building will be for the sodium hypochlorite and sodium bisulfite feed systems, a mechanical room, an electrical room, a storage/work area and plant water system. The grade level of the Operations/Lab Building will be used for operations and laboratory space.

Other design items for this building include:

File and storage areas SCADA/operations area One office Laboratory with lab office and storage Lunch Room Mens and womens locker rooms

2.3.20 Plant Security

The design will include a new main plant security gate that would be open during operating hours. During off hours the gate would be closed, but can be opened with remote controls or override key. An intercom, security camera and fire department lock box will be provided at the main gate. The video signal from the camera will be brought back to a facility video management system in the Operations/Lab Building.

The first floor of the Operations/Lab Building will be provided door with contacts only. All other buildings and rooms at the WWTF will be provided with door locks only. The security system for the main plant security gate and the door contacts at the Operations/Lab Building will be connected to the SCADA system.

2.3.21 Demolition

The following structures will be demolished as part design of the facility upgrades:

Existing odor control system Existing Administration Building Existing Filter Building Existing Solids Processing Building (refer to Appendix C for more information) Portions of the existing Effluent Meter Structure Garage near existing Effluent Meter Structure Portions of the existing Chlorine Contact Tanks Existing Filtrate Pump Station Existing drainage manhole east of the existing Solids Processing Building

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3 WWTF FLOWS, LOADING AND EFFLUENT LIMITS

3.1 Design Flows

3.1.1 Design Flows to Secondary Treatment

The design our flows for the WWTF upgrade were developed as part of the Design Phase 1 Summary Memorandum dated March 2014 using the same methodology presented in the Revised Flow and Loading Technical Memorandum dated August 27, 2012.

Table 3-1 displays the existing conditions flow rates.

Table 3-1. Existing Condition Flow Rates to Secondary Treatment

(January 1, 2008 to June 30, 2012)

Flow Scenario Flow (MGD) Peaking Factor (to annual average day)Minimum Day Flow 1 2.66 0.51 Minimum Month Flow 2 3.42 0.65 Parsed Dry Average Day 4.34 0.83 Average Annual Flow 3 5.23 1.00 Maximum Month Flow 4 7.56 1.44 Maximum Day Dry Weather Flow 5 7.73 1.48 Peak Hour Dry Weather Flow 6 9.00 1.72

1. Minimum daily flow of all days in reporting period with wet weather days capped at the maximum parsed dry day flow of 7.73 mgd.

2. Minimum value of a 30 day rolling average of all days in reporting period with wet weather days capped at the maximum parsed dry day flow of 7.73 mgd.

3. Average of all days in reporting period with wet weather days capped at the maximum parsed dry day flow of 7.73 mgd (see note 3).

4. Maximum value of a 30 day rolling average of all days in reporting period with wet weather days capped at the maximum parsed dry day flow of 7.73 mgd.

5. Maximum daily flow of parsed dry days in 4.5 year reporting period (January 1, 2008 to June 30, 2012). 6. Maximum instantaneous flow of parsed dry days between January 1, 2008 to June 30, 2012) excluding outliers. 7. Note values shown in bold were calculated values for this table.

The flow projections in Table 3-1 are based on an analysis of current wastewater flows and do not contain any allowance for future wastewater flow increases due to growth. Table 3-2 presents the year 2012 and the year 2032 projected flows to the secondary treatment process developed using the methodology outlined above.

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Table 3-2. Secondary Treatment Process Design Flow Rates

Flow Scenario 2012 Flow

(MGD) Peaking Factor (to

average day) Projected 20 Year Flow

Increase (MGD) 2032 Flow

(MGD) Secondary Treatment Minimum Day 2.66 0.51 0.46 3.12

Secondary Treatment Minimum Month 3.42 0.65 0.59 4.01

Secondary Treatment Average Annual Flow 5.23 1.00 0.9 6.13

Secondary Treatment Maximum Month 7.56 1.44 1.30 8.86

Secondary Treatment Maximum Day 7.73 1.48 1.33 9.06

Secondary Treatment Peak Hour 9.00 1.48 1.33 10.33

1. Note values shown in bold were calculated values for this table.

3.1.2 Raw Influent Design Flows

Table 3-1 and Table 3-2 above present the design flows through secondary treatment which were calculated using the parsed dry weather flow data set. Table 3-3 presents the maximum design flows for the plant influent based on the complete data set between January 1, 2008 and December 31, 2012. Future flow increases in the maximum day and maximum hour flow have not been accounted for in Table 3-3 because of the Citys ongoing efforts to reduce infiltration and inflow in the collection system through the ongoing sewer separation program.

Table 3-3. WWTF Influent Maximum Design Flow Rates

Criteria 2012 Flow

(MGD)

Projected 20 Year Flow

Increase (MGD)2032 Flow

(MGD) Maximum Day1 19.4 - 19.4 Maximum Hour2 22 - 22

1. Maximum daily flow between January 1, 2008 and December 31, 2012. 2. Maximum hour flow between January 1, 2008 and December 31, 2012. 3. No projected increase in flow since these flows are wet weather from combined sewer system.

3.2 Design Loadings

The proposed design loadings were developed as part of the Design Phase 1 Summary Memorandum dated March 2014 using the same methodology presented in the Revised Flow and Loading Technical Memorandum.

Table 3-4 shows the projected year 2032 design flows and loads to the secondary treatment process.

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Table 3-4. Projected Year 2032 Design Flows and Loads to Secondary

Parameter Minimum

Day Minimum

Month Annual

Average Day Maximum

Month Maximum

Day

Flow (MGD) 3.12 4.01 6.13 8.86 9.06

Primary Effluent TSS (mg/L) 106 101 95 84 110 Primary Effluent TSS (lb/d) 3 2,761 3,359 4,878 6,234 8,332 Primary Effluent BOD5 (mg/L) 176 183 156 129 173 Primary Effluent BOD5 (lb/d) 3 4,564 6,124 7,967 9,505 13,080 Primary Effluent TKN (mg/l) 30.2 31.7 26.9 25.1 31.1 Primary Effluent TKN (lb/d) 4 784 1,058 1,375 1,856 2,351

CEPT Effluent TSS (mg/L) 57 54 52 46 60 CEPT Effluent TSS (lb/d) 1 1,492 1,815 2,636 3,369 4,502 CEPT Effluent BOD5 (mg/L) 136 142 121 100 134 CEPT Effluent BOD5 (lb/d) 1 3,532 4,740 6,166 7,356 10,123 CEPT Effluent TKN (mg/l) 27.2 28.6 24.2 22.6 28.0 CEPT Effluent TKN (lb/d) 2 706 954 1,239 1,672 2,118

1. Percent removals based on WWTF MOR loading data capped at the maximum parsed dry flow day of 7.73 mgd. 2. Percent removal based on WWTF characterization data (May 13, 2011 to March 3, 2012). 3. Percent removal based on observed pilot data, text book values, and approximately 1/2 of the CEPT removal. 4. Percent removal based on observed wastewater characterization data, text book values and approximately 1/2 of the CEPT removal. 5. Recycle loads are not included. The mass balances in Section 4 display the loadings with recycle loads taken into account.

3.3 Effluent Limits

Effluent from the Peirce Island WWTF is discharged to the Piscataqua River and is regulated by a National Pollutant Discharge Elimination System (NPDES) permit issued by the United States Environmental Protection Agency (USEPA). The City is in ongoing discussions with EPA regarding the effluent limits that will be imposed on the Peirce Island WWTF. Typical secondary treatment standards for BOD and TSS and a seasonal rolling average limit for total nitrogen have been based on these ongoing discussions for the purposes of design. The effluent limits being used for design are set forth in Table 3-5 below.

Table 3-5. Design Effluent Limits

Parameter Average Monthly Average Weekly Maximum Daily Seasonal Average1BOD5 30 mg/L 45 mg/L 50 mg/L - TSS 30 mg/L 45 mg/L 50 mg/L - Total Nitrogen - - - 8 mg/L pH Range 6.0 8.0 - Total Chlorine Residual 0.33 - 0.57 - Fecal Coliform 14 MPN/100 mL - - -

1. The total nitrogen season is assumed to be April through October.

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4 SOLIDS AND FLOW BALANCES

The solids and flow balances prepared for the project have been organized by major process area and are included on the following pages.

JOB # 60301525DATE 6/13/2014CALC. BY E. MESERVE/T.WASSELLCHKD BY M. LAQUIDARA

SOLIDS AND FLOW BALANCES

TN3 TN8 TN12 TN3 TN8 TN12 TN8 TN12 TN3 TN8 TN12 TN3 TN8 TN12 TN8 TN12

INFLUENTINFLUENT FLOW MGD 5.69 6.13 6.13 6.13 8.86 8.86 8.86 9.06 9.06 6.13 6.13 6.13 8.86 8.86 8.86 9.06 9.06 22PLANT RECYCLES MGD 1.05 0.29 0.29 0.29 0.29 0.29 0.29 0.28 0.28 0.29 0.29 0.29 0.29 0.29 0.29 0.28 0.28 0.28BAF BACKWASH MGD 0.00 2.03 2.03 2.03 2.03 2.03 2.03 2.03 2.03 1.60 1.60 1.60 1.60 1.60 1.60 1.60 1.60 0TOTAL FLOW MGD 6.74 8.44 8.44 8.44 11.17 11.17 11.17 11.37 11.37 8.02 8.02 8.02 10.75 10.75 10.75 10.95 10.95 22.28

BOD CONC. MG/L INFLUENT 159 203 202 201 170 170 169 228 227 202 201 201 169 169 168 227 226 RECYCLES 38 378 357 340 471 441 419 607 584 353 335 324 432 409 391 565 551 BACKWASH 520 480 448 650 596 555 807 766 454 412 386 559 506 465 688 657 TOTAL 197 1101 1040 990 1291 1207 1142 1642 1577 1009 948 911 1160 1083 1024 1480 1434

BOD LOAD LB/DAY INFLUENT 8,610 9,959 9,959 9,959 11,881 11,881 11,881 16,350 16,350 9,959 9,959 9,959 11,881 11,881 11,881 16,350 16,350 RECYCLES 334 906 856 816 1,119 1,050 998 1,429 1,377 845 803 777 1,026 972 931 1,330 1,298 BACKWASH 0 8,781 8,119 7,577 10,988 10,073 9,372 13,647 12,947 6,064 5,509 5,165 7,476 6,763 6,220 9,195 8,778 TOTAL 8,944 19,645 18,934 18,351 23,987 23,004 22,250 31,426 30,674 16,868 16,271 15,901 20,383 19,616 19,032 26,875 26,426

TSS CONC. MG/L INFLUENT 167 221 219 218 198 196 195 256 255 221 220 219 198 197 196 257 257 RECYCLES 115 863 827 793 1100 1048 1003 1410 1376 874 839 818 1111 1067 1032 1446 1421 BACKWASH 665 623 581 838 777 723 1032 992 568 517 487 707 643 592 866 831 TOTAL 282 1749 1669 1592 2135 2021 1921 2698 2623 1664 1575 1524 2016 1907 1819 2569 2509

TSS LOAD LB/D INFLUENT 8,372 9,756 9,756 9,756 12,468 12,468 12,468 16,664 16,664 9,756 9,756 9,756 12,468 12,468 12,468 16,664 16,664 RECYCLES 1,010 2,057 1,973 1,893 2,604 2,483 2,381 3,310 3,231 2,082 1,999 1,952 2,629 2,527 2,446 3,389 3,333 BACKWASH 0 11,240 10,523 9,826 14,157 13,125 12,225 17,438 16,761 7,599 6,907 6,515 9,447 8,600 7,916 11,576 11,113 TOTAL 9,382 23,052 22,252 21,475 29,229 28,077 27,073 37,412 36,656 19,437 18,662 18,222 24,543 23,595 22,830 31,629 31,110

TKN CONC. MG/L INFLUENT 23 30 30 29 28 28 28 35 35 30 30 29 28 28 28 35 35 RECYCLES 3 32 30 28 41 38 36 50 48 31 29 28 39 37 35 49 48 BACKWASH 50 47 43 63 58 54 76 73 46 42 39 58 52 48 69 66 TOTAL 26 112 106 101 132 124 117 160 155 107 100 96 125 117 111 153 149

TKN LOAD LB/D INFLUENT 1,289 1,511 1,511 1,511 2,039 2,039 2,039 2,583 2,583 1,511 1,511 1,511 2,039 2,039 2,039 2,583 2,583 RECYCLES 23 76 72 67 97 90 85 117 113 73 69 66 94 88 84 115 112 BACKWASH 0 850 791 734 1,066 981 912 1,283 1,228 621 563 526 771 695 639 926 887 TOTAL 1,312 2,437 2,373 2,313 3,202 3,110 3,036 3,983 3,925 2,205 2,143 2,104 2,904 2,822 2,762 3,624 3,583

FUTURE 2033

EXISTING2013

NON-CEPT CEPTPEAK HOURAVERAGE DAY MAX MONTH MAX DAY AVERAGE DAY MAX MONTH MAX DAY

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FUTURE 2033

EXISTING2013


PRIMARY TREATMENTPRIMARY EFFLUENT TOTAL FLOW MGD 5.70 8.33 8.33 8.34 11.03 11.03 11.04 11.19 11.19 7.91 7.91 7.91 10.60 10.61 10.61 10.76 10.76 BOD LOAD LB/DAY 5,537 10,405 10,198 10,028 12,573 12,287 12,068 16,842 16,623 8,246 8,077 7,973 9,911 9,694 9,529 13,307 13,180 TSS LOAD LB/D 2,411 8,795 8,569 8,350 11,174 10,849 10,566 14,468 14,255 4,995 4,796 4,683 6,308 6,064 5,867 8,129 7,995 TKN LOAD LB/D 1,076 1,663 1,643 1,625 2,217 2,190 2,167 2,787 2,769 1,459 1,440 1,429 1,947 1,923 1,905 2,450 2,438

PRIMARY % REMOVAL BOD 38 47 46 45 48 47 46 46 46 51 50 50 51 51 50 50 50 TSS 74 62 61 61 62 61 61 61 61 74 74 74 74 74 74 74 74 TKN 18 32 31 30 31 30 29 30 29 34 33 32 33 32 31 32 32

PRIMARY SLUDGE TOTAL FLOW MGD 1.04 0.11 0.11 0.10 0.14 0.14 0.13 0.18 0.18 0.12 0.11 0.11 0.15 0.14 0.14 0.19 0.18 BOD LOAD LB/DAY 3,408 9,240 8,736 8,323 11,414 10,717 10,183 14,584 14,051 8,622 8,193 7,928 10,472 9,922 9,503 13,568 13,246 TSS LOAD LB/D 6,971 14,258 13,683 13,125 18,055 17,228 16,507 22,943 22,401 14,442 13,866 13,539 18,236 17,531 16,963 23,500 23,114 TKN LOAD LB/D 236 775 730 687 984 921 868 1196 1155 747 703 675 957 899 857 1174 1144 % SOLIDS 0.08 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5

SECONDARY TREATMENTCN BAF TOTAL FLOW MGD 8.33 8.33 8.34 11.03 11.03 11.04 11.19 11.19 7.91 7.91 7.91 10.60 10.61 10.61 10.76 10.76

CN EFFLUENT CONC. MG/L BOD 17 18 18 17 17 17 20 20 18 18 18 18 18 18 20 21 TSS 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 TKN 3 3 3 3 3 3 4 4 NO3 11 11 11 12 12 12 14 14 12 12 12 13 13 13 16 15

CN EFFLUENT LOAD LB/DAY BOD 1209 1216 1217 1573 1583 1575 1828 1857 1187 1187 1194 1556 1566 1558 1821 1858 TSS 1042 1043 1043 1380 1380 1381 1399 1391 989 990 990 1326 1327 1328 1346 1346 TKN 241 243 243 298 299 301 341 343 NO3 764 744 737 1104 1086 1077 1325 1288 811 805 799 1150 1141 1133 1391 1364

CN EFFLUENT % REMOVAL BOD 88 88 88 87 87 87 89 89 86 85 85 84 84 84 86 86 TSS 88 88 88 88 87 87 90 90 80 79 79 79 78 77 83 83 TKN 86 85 85 87 86 86 88 88 100 100 100 100 100 100 100 100

CN BACKWASH CONC. MG/L BOD 534 523 516 636 622 612 834 827 469 449 446 543 524 509 721 720 TSS 685 679 669 824 813 800 1066 1070 589 564 563 690 669 650 909 912 TKN 52 51 50 62 61 60 78 78 48 46 45 55 54 52 72 73





FUTURE 2033

EXISTING2013


CN BACKWASH LOAD LB/DAY BOD 7,270 7,129 7,025 8,672 8,472 8,337 11,367 11,265 4,732 4,533 4,505 5,486 5,288 5,144 7,281 7,268 TSS 9,327 9,257 9,113 11,223 11,080 10,895 14,520 14,584 5,947 5,691 5,680 6,970 6,752 6,560 9,177 9,208 TKN 703 695 681 840 825 811 1,067 1,069 481 461 459 560 540 527 728 732

DAILY AVG BACKWASH FLOW, MGD 1.63 1.63 1.63 1.63 1.63 1.63 1.63 1.63 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21PEAK BACKWASH FLOW, MGD 4.36 4.36 4.36 4.36 4.36 4.36 4.36 4.36 3.23 3.23 3.23 3.23 3.23 3.23 3.23 3.23

DN BAF TOTAL FLOW MGD 6.70 6.70 6.71 9.39 9.40 9.41 9.55 9.56 6.69 6.70 6.70 9.39 9.40 9.40 9.55 9.55

DN EFFLUENT CONC. MG/L BOD 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 TSS 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 TN3 3 3 3 3 TN8 8 8 8 8 8 8 TN12 12 12 12 12 12 12

DN EFFLUENT LOAD LB/DAY BOD 1675 1677 1678 2350 2352 2354 2390 2391 1675 1676 1677 2350 2351 2353 2389 2390 TSS 1675 1677 1678 2350 2352 2354 2390 2391 1675 1676 1677 2350 2351 2353 2389 2390 TN3 168 235 167 235 TN8 447 627 637 447 627 637 TN12 671 941 956 671 941 956

DN EFFLUENT % REMOVAL BOD 83 83 83 80 80 80 85 85 83 83 83 80 80 80 85 85 TSS 83 83 83 81 81 81 86 86 83 83 83 81 81 81 86 86 TN3 89 88 89 88 TN8 70 69 75 70 69 75 TN12 56 54 63 56 54 63

DN BACKWASH CONC. MG/L BOD 461 303 169 707 489 316 696 514 407 298 202 608 451 329 585 461 TSS 584 387 218 896 625 406 891 665 505 371 255 757 565 414 733 582 TKN 45 29 16 69 48 31 66 49 43 31 21 64 47 34 61 47

DN BACKWASH LOAD LB/DAY BOD 1,511 990 552 2,315 1,602 1,034 2,280 1,681 1,332 975 660 1,990 1,475 1,076 1,915 1,511 TSS 1,913 1,267 713 2,934 2,045 1,330 2,918 2,178 1,652 1,216 834 2,477 1,848 1,356 2,398 1,905 TKN 147 96 53 226 156 100 216 159 140 103 68 211 155 112 198 155

DAILY AVG BACKWASH FLOW, MGD 0.39 0.39 0.39 0.39 0.39 0.39 0.39 0.39 0.39 0.39 0.39 0.39 0.39 0.39 0.39 0.39PEAK BACKWASH FLOW, MGD 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05





FUTURE 2033

EXISTING2013


GRAVITY THICKENEROVERFLOW TOTAL FLOW MGD 1.04 0.27 0.27 0.27 0.27 0.27 0.27 0.26 0.26 0.27 0.27 0.27 0.27 0.27 0.27 0.26 0.26 BOD LOAD LB/DAY 256 693 655 624 856 804 764 1,094 1,054 647 614 595 785 744 713 1,018 993 TSS LOAD LB/D 697 1,426 1,368 1,313 1,805 1,723 1,651 2,294 2,240 1,444 1,387 1,354 1,824 1,753 1,696 2,350 2,311 TKN LOAD LB/D 18 58 55 52 74 69 65 90 87 56 53 51 72 67 64 88 86

OVERFLOW BOD CONC. MG/L 305 287 273 385 360 340 506 486 285 270 260 353 333 318 472 460 TSS CONC. MG/L 627 600 574 811 771 735 1061 1033 636 608 593 820 786 758 1091 1070 TKN CONC. MG/L 26 24 23 33 31 29 41 40 25 23 22 32 30 29 41 40

THICKENED SLUDGE TOTAL FLOW GPD 9,403 21,980 21,095 20,234 27,834 26,559 25,448 35,370 34,534 22,264 21,376 20,872 28,113 27,026 26,150 36,229 35,634 BOD LOAD LB/DAY 3,152 8,547 8,081 7,699 10,558 9,913 9,419 13,491 12,997 7,975 7,579 7,333 9,687 9,178 8,790 12,551 12,253 TSS LOAD LB/D 6,273 12,832 12,315 11,813 16,249 15,505 14,857 20,649 20,161 12,998 12,479 12,185 16,412 15,778 15,267 21,150 20,803 TKN LOAD LB/D 218 717 675 636 911 852 803 1107 1069 691 650 624 885 832 793 1086 1059 % SOLIDS 8.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0

DEWATERINGFEED SOLIDS TOTAL FLOW GAL/HR 3,839 7,180 6,891 6,610 7,793 7,436 7,125 8,253 8,058 7,273 6,983 6,818 7,872 7,567 7,322 8,453 8,315 BOD LOAD LB/DAY 3,152 8,547 8,081 7,699 10,558 9,913 9,419 13,491 12,997 7,975 7,579 7,333 9,687 9,178 8,790 12,551 12,253 TSS LOAD LB/D 6,273 12,832 12,315 11,813 16,249 15,505 14,857 20,649 20,161 12,998 12,479 12,185 16,412 15,778 15,267 21,150 20,803 TKN LOAD LB/D 218 717 675 636 911 852 803 1107 1069 691 650 624 885 832 793 1086 1059 % SOLIDS 8 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7

DEWATERED CAKE TOTAL FLOW GPD 2,382 7,308 7,014 6,728 9,255 8,831 8,462 11,760 11,483 7,403 7,108 6,940 9,347 8,986 8,695 12,046 11,848 BOD LOAD LB/DAY 3,073 8,333 7,879 7,507 10,294 9,666 9,184 13,153 12,672 7,776 7,389 7,150 9,445 8,948 8,570 12,237 11,946 TSS LOAD LB/D 5,960 12,190 11,699 11,222 15,437 14,730 14,114 19,616 19,153 12,348 11,855 11,576 15,591 14,989 14,503 20,093 19,763 TKN LOAD LB/D 213 699 658 620 888 830 783 1,079 1,042 673 634 609 863 811 773 1,058 1,032 % SOLIDS 30.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0

PRESSATE TOTAL FLOW GPD 7,021 14,672 14,081 13,506 18,579 17,728 16,987 23,609 23,051 14,861 14,269 13,932 18,765 18,040 17,455 24,183 23,785 BOD LOAD LB/DAY 79 214 202 192 264 248 235 337 325 199 189 183 242 229 220 314 306 TSS LOAD LB/D 314 15 15 15 15 15 15 15 1,008 15 15 15 15 15 15 15 1,040 TKN LOAD LB/D 5 18 17 16 23 21 20 28 27 17 16 16 22 21 20 27 26 BOD LOAD MG/L 1345.9 1746.3 1720.4 1708.7 1703.4 1676.2 1662.2 1712.8 1690.2 1608.7 1592.2 1577.8 1547.4 1525.0 1509.5 1555.7 1544.2 TSS LOAD MG/L 5357.1 122.6 127.7 133.2 96.8 101.5 105.9 76.2 5243.4 121.0 126.1 129.1 95.8 99.7 103.0 74.4 5243.4 TKN LOAD MG/L 93.3 146.4 143.8 141.1 146.9 144.0 141.8 140.5 139.0 139.3 136.6 134.3 141.4 138.3 136.1 134.6 133.4

NOTES:1. TN3 = EFFLUENT LIMIT OF SEASONAL ROLLING AVERAGE OF 3 MG/L TOTAL NITROGEN BETWEEN APRIL AND OCTOBER.2. TN8 = EFFLUENT LIMIT OF SEASONAL ROLLING AVERAGE OF 3 MG/L TOTAL NITROGEN BETWEEN APRIL AND OCTOBER.3. TN12 = EFFLUENT LIMIT OF SEASONAL ROLLING AVERAGE OF 3 MG/L TOTAL NITROGEN BETWEEN APRIL AND OCTOBER.


5-1

5 BASIC DESIGN DATA

Basic design data for the various proposed unit processes throughout the upgraded facility are presented on the following pages.


BASIC DESIGN DATASCREENINGS


DESIGN CRITERIA

FLOW (INFLUENT + RECYCLES) MGD 6.74 6.42 6.42 6.42 9.15 9.15 9.15 9.34 9.34 6.42 6.42 6.42 9.15 9.15 9.15 9.34 9.34 22.28

SCREEN OPENING, MM 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6UPPER RANGE SCREENING QTY, FT3/MG 9.75 9.75 9.75 9.75 9.75 9.75 9.75 9.75 9.75 9.75 9.75 9.75 9.75 9.75 9.75 9.75 9.75AVERAGE SCREENING QTY, FT3/MG 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5LOWER RANGE SCREENING QTY, FT3/MG 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5

UPPER RANGE WET SCREENINGS, FT3/D 63 63 63 89 89 89 91 91 63 63 63 89 89 89 91 91 217AVERAGE WET SCREENINGS, FT3/D 48 48 48 69 69 69 70 70 48 48 48 69 69 69 70 70 167LOWER RANGE WET SCREENINGS, FT3/D 32 32 32 46 46 46 47 47 32 32 32 46 46 46 47 47 111

DRY/WET SCREENINGS 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25

UPPER RANGE DRY SCREENINGS, FT3/D 16 16 16 22 22 22 23 23 16 16 16 22 22 22 23 23 54AVERAGE DRY SCREENINGS, FT3/D 12 12 12 17 17 17 18 18 12 12 12 17 17 17 18 18 42LOWER RANGE DRY SCREENINGS, FT3/D 8 8 8 11 11 11 12 12 8 8 8 11 11 11 12 12 28

UPPER RANGE DRY SCREENINGS, CY/D 0.58 0.58 0.58 0.83 0.83 0.83 0.84 0.84 0.58 0.58 0.58 0.83 0.83 0.83 0.84 0.84 2.01AVERAGE DRY SCREENINGS, CY/D 0.45 0.45 0.45 0.64 0.64 0.64 0.65 0.65 0.45 0.45 0.45 0.64 0.64 0.64 0.65 0.65 1.55LOWER RANGE DRY SCREENINGS, CY/D 0.30 0.30 0.30 0.42 0.42 0.42 0.43 0.43 0.30 0.30 0.30 0.42 0.42 0.42 0.43 0.43 1.03

NOTES:1. TN3 = EFFLUENT LIMIT OF SEASONAL ROLLING AVERAGE OF 3 MG/L TOTAL NITROGEN BETWEEN APRIL AND OCTOBER.2. TN8 = EFFLUENT LIMIT OF SEASONAL ROLLING AVERAGE OF 3 MG/L TOTAL NITROGEN BETWEEN APRIL AND OCTOBER.3. TN12 = EFFLUENT LIMIT OF SEASONAL ROLLING AVERAGE OF 3 MG/L TOTAL NITROGEN BETWEEN APRIL AND OCTOBER.

FUTURE 2033

EXISTING2013

NON-CEPT CEPTPEAK HOUR

AVERAGE DAY MAX MONTH MAX DAY AVERAGE DAY MAX MONTH MAX DAY

1 of 25 Peirce Island Process Design and Mass Balance Rev16.xlsx

JOB # 60301525DATE 7/15/2014CALC. BY E. MESERVE/T. WASSELLCHKD BY M. LAQUIDARA

BASIC DESIGN DATAAERATED GRIT CHAMBERS


DESIGN CRITERIA

FLOW (INFLUENT + RECYCLES) MGD 6.74 6.42 6.42 6.42 9.15 9.15 9.15 9.34 9.34 6.42 6.42 6.42 9.15 9.15 9.15 9.34 9.34 22.28FLOW GPM 4,679 4,454 4,454 4,454 6,347 6,347 6,347 6,484 6,484 4,454 4,454 4,454 6,347 6,347 6,347 6,484 6,484 15,464DESIRED DETENTIONTIME @ MAX HR. MIN 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3

VOLUME REQD GALS. 14,036 13,361 13,361 13,362 19,041 19,042 19,042 19,452 19,452 13,361 13,361 13,362 19,040 19,041 19,042 19,451 19,452 46,393VOLUME REQD. CFT 1,877 1,786 1,786 1,786 2,546 2,546 2,546 2,601 2,601 1,786 1,786 1,786 2,546 2,546 2,546 2,600 2,600 6,202

FINAL DESIGNNUMBER OF UNITS 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2NUMBER IN SERVICE 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2UNIT VOLUME CFT 938 893 893 893 1,273 1,273 1,273 1,300 1,300 893 893 893 1,273 1,273 1,273 1,300 1,300 3,101DEPTH FT 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00WIDTH FT 16.50 16.50 16.50 16.50 16.50 16.50 16.50 16.50 16.50 16.50 16.50 16.50 16.50 16.50 16.50 16.50 16.50 16.50DESIGN LENGTH FT 18.42 18.42 18.42 18.42 18.42 18.42 18.42 18.42 18.42 18.42 18.42 18.42 18.42 18.42 18.42 18.42 18.42 18.42UNIT VOLUME CFT 3,039 3,039 3,039 3,039 3,039 3,039 3,039 3,039 3,039 3,039 3,039 3,039 3,039 3,039 3,039 3,039 3,039 3,039VOLUME IN SERVICE CFT 6,079 6,079 6,079 6,079 6,079 6,079 6,079 6,079 6,079 6,079 6,079 6,079 6,079 6,079 6,0

Documents

July 2014 – Peirce Island WWTF Upgrade Preliminary (30 Percent)