Cip Project Development for Plant No. 2 Solids Handling Facilities

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ORANGE COUNTY SANITATION DISTRICT BIOSOLIDS MASTER PLAN

TECHNICAL MEMORANDUM 6: CIP PROJECT DEVELOPMENT FOR PLANT NO. 2 SOLIDS HANDLING FACILITIES

OCSD PROJECT NO. PS15‐01 reserved. rights

All

2015.

Company

Holding

Veatch

Orange County Sanitation District

©Black 9 MAY 2017

In association with

TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Table of Contents Acronym and Abbreviations List ...... x Executive Summary ...... ES‐1 1.0 Introduction ...... 1‐1 1.1 Purpose ...... 1‐1 1.2 Approach ...... 1‐1 2.0 Background ...... 2‐1 2.1 Summary of TM‐4 Findings ...... 2‐1 2.2 Summary of TM‐5 Findings ...... 2‐1 2.3 Geotechnical Evaluation of Proposed Facilities ...... 2‐2 3.0 Process Requirements for Future Digestion and Pre‐Processed SSO Co‐Digestion Facilities ...... 3‐1 3.1 Solids Flows and Loads ...... 3‐1 3.2 Pre‐Processed SSO Loads ...... 3‐1 3.3 Design Criteria ...... 3‐2 3.4 Process Performance ...... 3‐3 3.4.1 Digester Performance ...... 3‐3 3.4.2 Digester Gas Production ...... 3‐4 3.5 Process Heat Demand ...... 3‐6 4.0 Conceptual Design for Future Digestion and Pre‐Processed SSO Co‐Digestion Facilities ...... 4‐1 4.1 Process Flow Diagram ...... 4‐1 4.2 Process Design ...... 4‐2 4.2.1 Thermophilic Digesters (110‐ft Diameter) ...... 4‐2 4.2.1.1 Description ...... 4‐2 4.2.1.2 Major Equipment List ...... 4‐3 4.2.1.3 Facility Layout ...... 4‐3 4.2.2 Mesophilic Digesters (105‐ft Diameter) ...... 4‐5 4.2.2.1 Description ...... 4‐5 4.2.2.2 Major Equipment List ...... 4‐6 4.2.2.3 Facility Layout ...... 4‐6 4.2.3 Mesophilic Digesters (80‐ft Diameter) ...... 4‐7 4.2.3.1 Description ...... 4‐7 4.2.3.2 Major Equipment List ...... 4‐7 4.2.3.3 Facility Layout ...... 4‐8 4.2.4 Digested Sludge Holders (80‐ft Diameter) ...... 4‐9 4.2.4.1 Description ...... 4‐9 4.2.4.2 Major Equipment List ...... 4‐9 4.2.4.3 Facility Layout ...... 4‐10 4.2.5 Digester Feed Facility (DFF) ...... 4‐10

Final – May 9, 2017 ii Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

4.2.5.1 Description ...... 4‐10 4.2.5.2 Major Equipment List ...... 4‐11 4.2.5.3 Facility Layout ...... 4‐11 4.2.6 TPAD Class A Batch Tanks ...... 4‐12 4.2.6.1 Class A Batch Tank Evaluation and Justification ...... 4‐13 4.2.6.2 Reactivation and Regrowth Potential with Class A ...... 4‐15 4.2.6.3 Class A Batch Tank Number and Sizing ...... 4‐16 4.2.6.4 Description ...... 4‐17 4.2.6.5 Facility Process Flow Diagram ...... 4‐17 4.2.6.6 Major Equipment List ...... 4‐18 4.2.6.7 Facility Layout ...... 4‐19 4.2.7 TPAD Sludge Cooling ...... 4‐19 4.2.7.1 Description ...... 4‐22 4.2.7.2 Major Equipment List ...... 4‐22 4.2.7.3 Facility Layout ...... 4‐22 4.2.8 Interim Pre‐Processed SSO Receiving ...... 4‐24 4.2.8.1 Description ...... 4‐24 4.2.8.2 Major Equipment List ...... 4‐26 4.2.8.3 Facility Layout ...... 4‐27 4.2.9 Ultimate Pre‐Processed SSO Receiving ...... 4‐28 4.2.9.1 Description ...... 4‐28 4.2.9.2 Major Equipment List ...... 4‐29 4.2.9.3 Facility Layout ...... 4‐29 4.2.10 Gas Handling Facilities ...... 4‐30 4.2.10.1 Major Equipment List ...... 4‐34 4.2.10.2 Facility Layout ...... 4‐34 4.2.11 Ferric Chloride Facility ...... 4‐35 4.2.11.1 Description ...... 4‐35 4.2.11.2 Major Equipment List ...... 4‐35 4.2.11.3 Facility Layout ...... 4‐35 4.2.12 Centrifuge Dewatering Facility ...... 4‐36 4.3 Site Layout ...... 4‐37 5.0 CIP Development for New Digestion and Pre‐Processed SSO Co‐Digestion Facilities ... 5‐1 5.1 P2‐501 – Perimeter Screening ...... 5‐1 5.1.1 Background ...... 5‐1 5.1.2 Project Elements ...... 5‐1 5.1.3 Sequencing ...... 5‐2 5.1.4 Construction Cost Estimate ...... 5‐2

Final – May 9, 2017 iii Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

5.2 P2‐502 – Interim PRE‐processed SSO Receiving Facility ...... 5‐2 5.2.1 Description ...... 5‐2 5.2.2 Project Elements ...... 5‐3 5.2.3 Sequencing ...... 5‐3 5.2.4 Construction Cost Estimate ...... 5‐3 5.3 P2‐503 – Relocate and Demo Warehouse and Collections Parking Area ...... 5‐4 5.3.1 Description ...... 5‐4 5.3.2 Project Elements ...... 5‐4 5.3.3 Sequencing ...... 5‐5 5.3.4 Construction Cost Estimate ...... 5‐5 5.4 P2‐504 – TPAD Project Elements ...... 5‐6 5.4.1 Project Elements ...... 5‐6 5.4.2 Sequencing ...... 5‐7 5.4.3 Construction Cost Estimate ...... 5‐8 5.5 P2‐504A – Class A Batch Tanks ...... 5‐8 5.5.1 Description ...... 5‐8 5.5.2 Project Elements ...... 5‐9 5.5.3 Sequencing ...... 5‐9 5.5.4 Construction Cost Estimate ...... 5‐9 5.6 P2‐504B – Digester Feed Facility (DFF) ...... 5‐10 5.6.1 Description ...... 5‐10 5.6.2 Project Elements ...... 5‐10 5.6.3 Sequencing ...... 5‐11 5.6.4 Construction Cost Estimate ...... 5‐11 5.7 P2‐504C – Ferric Chloride Facility ...... 5‐11 5.7.1 Background ...... 5‐11 5.7.2 Project Elements ...... 5‐11 5.7.3 Sequencing ...... 5‐12 5.7.4 Construction Cost Estimate ...... 5‐12 5.8 P2‐505 – Replace Digesters P, Q, R, S ...... 5‐12 5.8.1 Background ...... 5‐12 5.8.2 Project Elements ...... 5‐12 5.8.3 Sequencing ...... 5‐13 5.8.4 Construction Cost Estimate ...... 5‐13 5.9 P2‐506 – Ultimate PRE‐Processed SSO Receiving Facility ...... 5‐13 5.9.1 Background ...... 5‐13 5.9.2 Project Elements ...... 5‐14 5.9.3 Sequencing ...... 5‐14

Final – May 9, 2017 iv Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

5.9.4 Construction Cost Estimate ...... 5‐14 5.10 P2‐507 – Relocate Digester‐Holders (Formerly I, J, K) ...... 5‐14 5.10.1 Background ...... 5‐15 5.10.2 Project Elements ...... 5‐15 5.10.3 Sequencing ...... 5‐15 5.10.4 Construction Cost Estimate ...... 5‐15 5.11 P2‐508 – Digester Demolition ...... 5‐16 5.11.1 Background ...... 5‐16 5.11.2 Project Elements ...... 5‐16 5.11.3 Sequencing ...... 5‐16 5.11.4 Construction Cost Estimate ...... 5‐16 6.0 Modifications to Existing CIP Projects ...... 6‐1 6.1 X‐032 – Dewatered Sludge Storage and Truck Loading Rehabilitation ...... 6‐1 6.2 J‐124 – Digester Gas handling Facilities ...... 6‐1 6.2.1 Recommended Design Considerations ...... 6‐2 6.2.2 Future Steam Boiler Coordination ...... 6‐2 6.2.3 Construction Cost Estimate ...... 6‐2 6.3 P2‐500 – Digester Repairs ...... 6‐2 6.3.1 Background ...... 6‐3 6.3.2 Project Elements ...... 6‐3 6.3.3 Sequencing ...... 6‐5 6.3.4 Construction Cost Estimate ...... 6‐5 7.0 Implementation Schedule and Sequencing ...... 7‐1 8.0 Program Cost ...... 8‐1 9.0 References ...... 9‐1

See Enclosed Flash Drive for Appendices Appendix A – Fault Hazard Study ...... A‐1 Appendix B – Geotechnical Feasibility Report ...... B‐1 Appendix C – Site Layouts ...... C‐1 Appendix D – Schedule ...... D‐1 Appendix E – Cost Estimates ...... E‐1 Appendix F – Meeting Presentation Slides and Meeting Minutes ...... F‐1 Appendix G – P2‐500 ...... G‐1 Appendix H – Task 6 Detailed Pre‐Processed SSO Calculations ...... H‐1 Appendix I – Dewatered Sludge Storage and Truck Loading Capacity Calculations ...... I‐1 Appendix J –TPAD Process Flow Diagram and Equipment List ...... J‐1 Appendix K – QC Review Affidavits ...... K‐1

Final – May 9, 2017 v Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Select Published Appendices Appendix C – Site Layouts ...... C‐1 Appendix D – Schedule ...... D‐1 Appendix E – Cost Estimates ...... E‐1 Appendix G – P2‐500 ...... G‐1 Appendix I – Dewatered Sludge Storage and Truck Loading Capacity Calculations ...... I‐1 Appendix J –TPAD Process Flow Diagram and Equipment List ...... J‐1

Final – May 9, 2017 vi Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

LIST OF FIGURES Figure ES‐1. Task Flow for BMP ...... ES‐3 Figure ES‐2. A Schematic of Plant No. 2 Site Layout ...... ES‐5 Figure ES‐3. A Summary of the Implementation Schedule ...... ES‐6 Figure 1‐1. Task Flow for BMP ...... 1‐2 Figure 2‐1. Projections of the Newport‐Inglewood Fault Zone ...... 2‐3 Figure 2‐2. CPT Testing Locations from Kleinfelder Geotechnical Investigation ...... 2‐4 Figure 4‐1. Overall TPAD Solids Process Flow Diagram ...... 4‐2 Figure 4‐2. Thermophilic Equipment Gallery Layout at Grade ...... 4‐4 Figure 4‐3. Thermophilic Equipment Gallery Layout below Grade ...... 4‐5 Figure 4‐4. Facility Layout of the 105‐ft Diameter Digesters ...... 4‐7 Figure 4‐5. Facility Layout of the 85ft Diameter Digesters ...... 4‐9 Figure 4‐6. Digester Feed Facility Layout ...... 4‐12 Figure 4‐7. Schematic of Class A TPAD with Batch Tanks ...... 4‐13 Figure 4‐8. The Net Present Value of Class B Versus Class A ...... 4‐15 Figure 4‐9. Class A Batch Tank Fill ‐ Hold ‐ Draw Flow Schematic ...... 4‐17 Figure 4‐10. Class A Batch Tank Schematic ...... 4‐18 Figure 4‐11. A Schematic of the Facility Layout for the Batch Tanks ...... 4 ‐ 1 9 Figure 4‐12. Process Flow Diagram of Sludge Cooling with Plant Effluent ...... 4‐20 Figure 4‐13. UN/NF Facility Layout ...... 4‐23 Figure 4‐14. Plant Water Cooling Pump Station ...... 4‐23 Figure 4‐15. Sludge Cooling Heat Exchangers ...... 4‐24 Figure 4‐16. General Process Flow Diagram for the Interim Pre‐Processed SSO Receiving Facility at Plant No. 2 ...... 4‐25 Figure 4‐17. Locations of Potential Interim Pre‐Processed SSO Receiving Facilities ...... 4‐26 Figure 4‐18. Conceptual Layout of the Interim Pre‐Processed SSO Receiving Facility ...... 4‐27 Figure 4‐19. Ultimate Pre‐Processed SSO Receiving Facility Process Schematic ...... 4‐28 Figure 4‐20. Ultimate Pre‐Processed SSO Receiving Facility ...... 4‐30 Figure 4‐21. Projected Peak 15‐day Digester Gas Flows for Plant No. 2 ...... 4‐33 Figure 4‐22. Gas Handling Facility Layout from SP‐141 ...... 4‐35 Figure 4‐23. A Diagram of the Ferric Chloride Facility Layout ...... 4‐36 Figure 4‐24. P2‐92 Future Footprint Concept from P2‐92 Preliminary Design Report ...... 4‐37 Figure 4‐25. Site Layout ...... 4‐38 Figure 5‐1. Drawing of the Existing and New Locations for the Warehouse ...... 5‐4 Figure 5‐2. An Aerial of the Collections Yard's Existing and Relocation Sites ...... 5‐5 Figure 6‐1. Digester Summary Indicating Original Construction Date, Major Repair Jobs, Dome Types, and Lining ...... 6‐3 Figure 6‐2. Revised Gas Compressor Building Layout to Accommodate Future Steam Boilers ...... 6‐6

Final – May 9, 2017 vii Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Figure 7‐1. Plant No. 2 CIP Implementation Schedule ...... 7‐2

LIST OF TABLES Table ES‐1. Estimate of Probable Construction Cost for Proposed Plant No. 2 Biosolids CIP ...... ES‐7 Table 2‐1. Pre‐Processed SSO Co‐Digestion Capacity ...... 2‐2 Table 3‐1. Plant No. 2 Recommended 2035 Design Loadings for New Digesters under Max 15‐Day Condition ...... 3‐1 Table 3‐2. Pre‐Processed SSO Co‐Digestion Capacity ...... 3‐1 Table 3‐3. Digestion Design Criteria ...... 3‐2 Table 3‐4. Digester Volumes ...... 3‐2 Table 3‐5. Summary of Digester Operating Conditions for the Interim Facility in 2028 with Pre‐Processed SSO1 ...... 3‐3 Table 3‐6. Summary of Digester Operating Conditions for TPAD Operation in 2045 with Pre‐processed SSO1 ...... 3‐4 Table 3‐7. Plant No. 2 TPAD Digester Gas Productions with the Interim Facility in 2028, scfm1,2 ...... 3‐5 Table 3‐8. Plant No. 2 TPAD Digester Gas Productions with the Ultimate Facility in 2045, scfm1,2 ...... 3‐5 Table 3‐9. Plant No. 1 Digester Gas Productions in 2045, scfm1,2 ...... 3‐6 Table 3‐10. Digester Heat Demand and Capacity of Existing Heat Recovery Equipment in 2035 ...... 3‐6 Table 4‐1. A Summary of the Major Equipment Required for this Project ...... 4‐3 Table 4‐2. The 105‐ft. Diameter Digester Major Equipment List ...... 4‐6 Table 4‐3. Major Equipment List for the 80‐ft Diameter Digesters ...... 4‐8 Table 4‐4. Summary of the Major Equipment List for the Holders ...... 4 ‐ 1 0 Table 4‐5. The DFF Major Equipment List ...... 4‐11 Table 4‐6. A Summary of Biosolids End Use Programs ...... 4‐14 Table 4‐7. End Use Unit Cost ...... 4‐14 Table 4‐8. Major Equipment List Required for Class A Batch Tanks...... 4‐18 Table 4‐9. Summary of the Major Equipment ...... 4‐22 Table 4‐10. SSO Receiving Facility Design Criteria ...... 4‐26 Table 4‐11. Major Equipment Comprising the Interim Food Waste Receiving Facility ...... 4‐27 Table 4‐12. Major Equipment Comprising the Interim Food Waste Receiving Facility ...... 4‐29 Table 4‐13. Digester Gas Productions from Plant No. 1 and Plant No. 2 under Condition 11 ...... 4‐31 Table 4‐14. Digester Gas Productions from Plant No. 1 and Plant No. 2 under Condition 21 ...... 4‐31 Table 4‐15. CenGen Digester Gas Utilization Capacity ...... 4‐32 Table 4‐16. Project J‐124 Digester Gas Design Capacities ...... 4‐33 Table 4‐17. Digester Gas Utilization Major Equipment List ...... 4‐34 Table 5‐1. Summary of Probable Construction Cost for P2‐501 ...... 5‐2

Final – May 9, 2017 viii Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Table 5‐2. Summary of Probable Construction Cost for P2‐502 ...... 5‐3 Table 5‐3. Summary of Probable Construction Cost for P2‐503 ...... 5‐5 Table 5‐4. Summary of Probable Construction Cost for P2‐504 ...... 5‐8 Table 5‐5. Summary of Probable Construction Cost for P2‐504A ...... 5 ‐ 1 0 Table 5‐6. Summary of Probable Construction Cost for P2‐504B ...... 5 ‐ 1 1 Table 5‐7. Summary of Probable Construction Cost for P2‐504C ...... 5 ‐ 1 2 Table 5‐8. Summary of Probable Construction Cost for P2‐505 ...... 5‐13 Table 5‐9. Summary of Probable Construction Cost for P2‐506 ...... 5‐14 Table 5‐10. Summary of Probable Construction Cost for P2‐507 ...... 5 ‐ 1 6 Table 5‐11. Summary of Probable Construction Cost for P2‐508 ...... 5 ‐ 1 7 Table 6‐1. P2‐500 Scope of Work Summary...... 6‐4 Table 7‐1. A Summary of the Projected CIP Scheduling ...... 7‐3 Table 8‐1. Estimate of Probable Construction Cost for Proposed Plant No. 2 Solids Handling CIP (Cost Estimate Basis: December 2016 dollars, unless specified below) ...... 8‐1

Final – May 9, 2017 ix Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Acronym and Abbreviations List The following acronyms and abbreviations are used in this document.

% Percent AACE American Association of Civil Engineers BMP Biosolids Master Plan BOD Biochemical oxygen demand BV/BC Team Black and Veatch/Brown and Caldwell Team °C Celsius CenGen Central Power Generation Systems CEQA California Environmental Quality Act CHEX Cooling heat exchanger CIP Capital Improvement Program CMAD conventional mesophilic anaerobic digestion CMU Concrete Masonry Unit CPT Cone Penetration Testing DAFT Dissolved air flotation thickener FRP Fiberglass reinforced plastic °F Fahrenheit ft Feet/foot gal gallon gpm Gallons per minute HEX Heat Exchangers hp Horsepower HRT Hydraulic retention time IRWD Irvine Ranch Water District lb pound LRBMP Long‐Range Biosolids Management Plan M Million MCC Motor control center MG Million gallons MGD Million gallons per day mg/L Milligrams per liter mmbtuh million british thermal units per hour

NH3 Ammonia NH3‐N Ammonia as Nitrogen NPV Net present value NTP Notice to Proceed O&M Operations & Maintenance OCSD Orange County Sanitation District PDR Preliminary Design Report pH Potential of hydrogen PS Primary sludge QTY Quantity SBF Sludge blending facility

Final – May 9, 2017 x Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities scf Standard cubic feet scfm Standard cubic feet per minute sq Square SSO Source separated organics SWEET Solid‐Water‐Energy‐Evaluation Tool TBD To be determined TF/SC Trickling Filter Solids Contact TKN Total Kjeldahl Nitrogen TM Technical Memorandum TPAD Temperature phased anaerobic digestion TPODS Treatment Plant Operational Data Summary TS Total solids TSFF Thickened Sludge Feed Facility TWAS Thickened Waste Activated Sludge UF/NF ultrafiltration / nanofiltration VSR Volatile solids reduction wtpd Wet tons per day WWTP Wastewater treatment plant

Final – May 9, 2017 xi Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Executive Summary This Technical Memorandum (TM) 6 CIP Project Development for Plant No. 2 Solids Handling Facilities presents the major elements of work involving the conceptual design, implementation schedule, construction cost estimates, and construction and operational impacts from the proposed projects identified under Task 4. This work was conducted under Task 6 of Orange County Sanitation District (OCSD) Project No. PS15‐01, Biosolids Master Plan (BMP).

OCSD had previously identified the need to perform process equipment and structural rehabilitation on the aging 18 digesters to maintain reliable operation of digesters at Plant No. 2. OCSD has had concerns with the structural deterioration of the digester domes, as the digesters date back from 1959 through 1979 and were constructed either without protective liners or liners with failure history. Anticipating the need for structural improvements, including dome replacements for multiple digesters, OCSD embarked on a structural/seismic hazard evaluation study.

The end‐to‐end approach involved evaluation of both plant process and biosolids end use programs to develop a comprehensive assessment of alternatives. This approach was divided into subtasks, each documented in a TM. Five TMs were previously developed and submitted to OCSD: TM‐1 OCSD Solids Facilities Summary and Design Basis, TM‐2 Review OCSD’s Biosolids Program and Summarize the Current State, Trends, and Outlook for Biosolids Management, TM‐3 Biosolids Management Alternatives Evaluation, TM‐4 Plant No. 2 Digestion and Post‐Dewatering Technologies Evaluation, and TM‐5 High Strength Organic Waste Co‐Digestion Evaluation. TM‐1 and TM‐2 form the basis for the project as a whole and were used to provide background and context for this TM. TM‐3 summarized market research and evaluation conducted to determine the biosolids products with the best market potential. Those selected products then served as the target products to be produced using on‐site solids handling technologies which was evaluated under Task 4, and the solids treatment processes were evaluated and selected for Plant No. 2 under Task 4. TM‐5 summarized the co‐digestion evaluation performed under the BMP. This evaluation led to the selection of co‐digestion projects for Plant No. 2, which is discussed in further detail in this TM.

This document is organized to include the following sections:  Section 1: Introduction

Final – May 9, 2017 ES‐1 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

 Section 2: Background  Section 3: Process Requirements for Future Digestion and Food Waste Co‐Digestion Facilities  Section 4: Conceptual Design for Future Digestion and Food Waste Co‐Digestion Facilities  Section 5: CIP Development for New Digestion and Food Waste Co‐Digestion Facilities  Section 6: Existing CIP Modification  Section 7: Implementation Schedule and Sequencing  Section 8: Program Costs

The following are highlights of each section in TM‐4.

Section 1 (Introduction) and Section 2 (Background)

Under a previous study (SP‐186), geotechnical exploration and analysis, as well as structural analysis of the Plant No. 2 digester site was evaluated for potential seismic risks due to known liquefaction risks at the Plant No. 2 site. The SP‐186 Study identified liquefaction and structural deficiencies as the primary seismic hazard that would lead to several inches of settlement and structural failure for several digesters. Ground and structural improvements were identified as one potential mitigation method of the seismic risks. A fault study was not part of the scope of the geotechnical study in SP‐186; however, review of previous studies identified multiple splays of the Newport‐Inglewood fault zone running through the existing digester complex. Based on this study, OCSD decided to construct new digesters. The purpose of PS15‐01 is to evaluate and select the future digestion process and associated new infrastructure to mitigate the seismic risk through a holistic, end‐to‐end evaluation approach.

Under Task 6.1 of the BMP, a geotechnical study was performed by Kleinfelder Inc. to determine relative activity and location of the faults, suitability for construction, and recommend ground improvements, as needed, resulting in a setback zone (safety buffer) as a no‐build zone for either habitable or critical structures. These more recent evaluations identified more approximate locations for fault lines and set boundaries for expansion of future solids process to avoid seismic risk.

This section summarizes the end to end approach developed for the PDR, graphically illustrated in Figure ES‐1. Tasks 1 and 2 document the existing plant processes and infrastructure, setting the basis for the existing facilities. Task 3 investigated the biosolids management opportunities and defined the financial and operational considerations related to different end use alternatives. Task 4 involved evaluation, definition, and selection of the major solids handling processes for Plant No. 2 in combination with associated end use opportunities. TM‐5 separately assessed the feasibility of co‐digestion facilities at Plant No. 2. These evaluations and recommendations have been developed into discrete projects for inclusion under the capital improvement program (CIP) developed as part of this Task.

Final – May 9, 2017 ES‐2 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Figure ES‐1. Task Flow for BMP

Section 3 (Process Requirements for Future Digestion and Pre‐Processed SSO Co‐Digestion Facilities)

Based on work performed under Task 4 and 5, the projected loads, documented in TM‐1, where used to determine the process requirements for future digestion and pre‐processed SSO co‐ digestion facilities. Design of the digestion facility was performed using Condition 3, whereas the pre‐processed SSO facility was designed based on capacity available using Conditions 1 and 2. Conditions 1 and 2 vary based on flow splits between Plants No. 1 and 2. Condition 1 assumes Plant No. 1 would receive 125 MGD, while Plant No. 2 received 75 MGD. Whereas, Condition 2 assumes an equal flow split between the two plants. Finally, Condition 3 assumes flows and loads produced at Plant No. 2 are at their design capacity.

A temperature phased anaerobic digestion (TPAD) process was selected in Task 4, including the construction of six new, 110‐ft diameter thermophilic digesters. The addition of Class A batch tanks would allow the facility to produce Class A biosolids. An effluent cooling system would be used to reduce the temperature of the thermophilic sludge down to mesophilic temperatures for further stabilization in the mesophilic digesters prior to dewatering.

Plant No.2 digesters could accept 137 to 580 wet tons per day (wtpd) of pre‐processed Source Separated Organics (SSO) in 2028 with the existing digestion system, depending on solids flow and loads conditions. Following the construction of six 110‐ft diameter thermophilic digesters and operation in TPAD (anticipated at the end of 2028), the capacity of the pre‐processed SSO receiving capacity would increase to 320 to 810 wtpd of pre‐processed SSO. Based on the digester capacity evaluations results and understanding of the Plant No. 2 facility, the BV/BC team recommended to build an interim pre‐processed SSO receiving facility for the existing mesophilic digesters and an ultimate pre‐processed SSO receiving facility for the future TPAD digesters. The recommended capacity for the interim receiving facility is 250 wtpd, while the recommended capacity for the ultimate receiving facility is 500 wtpd. It is also recommended that the contracts with waste haulers should allow OCSD to accept less pre‐processed SSO than the maximum capacity of the receiving facility under certain conditions.

In addition to the solids flows and loads, the capacity of the gas handling system was evaluated. It was determined that the system could handle the excess gas production from co‐digestion with pre‐ processed SSO.

Final – May 9, 2017 ES‐3 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Section 4 (Conceptual Design for Future Digestion and Pre‐Processed SSO Co‐Digestion Facilities)

The conceptual design for future digestion and pre‐processed SSO co‐digestion facilities includes the TPAD processes, the ancillary TPAD facilities, and pre‐processed SSO receiving facilities. The TPAD process includes anaerobic digestions: six thermophilic digesters, six mesophilic digesters, two mesophilic holders, Class A batch tanks, digester feed facility, and TPAD sludge cooling. Ancillary facilities supporting TPAD operation include: pre‐processed SSO receiving, Digester gas handling equipment, ferric chloride addition, hot water loop improvements, and new steam boilers. The interim and ultimate pre‐processed SSO facilities would allow receiving and co‐digestion of source separated organics.

Section 5 (CIP Development for New Digestion and Pre‐Processed SSO Co‐Digestion Facilities)

TM‐4 identified projects necessary to upgrade the Plant No. 2 solids handling facilities in alignment with OCSD’s goals and objectives. This section reviews the design criteria used for sizing major equipment (as detailed in TM‐4) and establishes the discrete capital projects identified for the new digestion and pre‐processed SSO co‐digestion facilities, which can be summarized as follows and shown graphically in Figure ES‐2:  P2‐501 Perimeter Screening  P2‐502 Interim Pre‐processed SSO Receiving Facility  P2‐503 Relocate and Demo Warehouse and Collections Parking Area  P2‐504 TPAD Project  P2‐504A Class A Batch Tanks  P2‐504B Thickened Sludge Feed Facility  P2‐504C Ferric Chloride Facility  P2‐505 Replace Digesters P, Q, R, S  P2‐506 Ultimate Pre‐processed SSO Receiving Facility  P2‐507 Relocate Digesters‐Holders (Formerly I, J, K)  P2‐508 Digester Demolition

Final – May 9, 2017 ES‐4 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Figure ES‐2. A Schematic of Plant No. 2 Site Layout

Section 6 (Modification to Existing CIP Projects)

OCSD’s existing Asset Management Plan for Fiscal Years 2013‐14 and 2014‐15 document the investment strategy for Plant No. 2 capital projects. In addition to the new facilities described in Section 3, decisions made under Tasks 4 and 5 impact the existing planning for solids handling capital projects at Plant No. 2. The BV/BC Team identified the projects that were integral to the implementation of the full program, and these include:  X‐032 Solids Storage and Truck Loading  J‐124 Digester Gas Handling Facilities  P2‐500 Digester Repairs (formerly P2‐91‐1)

Two of these projects were previously identified by OCSD, P2‐500 Interim Digester Repairs (formerly P2‐91‐1) and J‐124 Digester Gas Handling Facilities. In order to maintain the integrity of the existing solids handling facilities during planning, design, and construction of the solids handling facilities upgrades, OCSD has a routine maintenance program. To ensure that this program is funded to support activities associated with digester maintenance, including cleaning, at Plant No. 2, the BV/BC Team identified this as P2‐500 for capital planning purposes. J‐124 was an existing project for OCSD, but would require a modification in scope following the Task 4 selection of TPAD and Task 5 selection of pre‐processed SSO digestion. This modified scope is described in this section. In addition, Project X‐032 is the project developed by OCSD Planning Staff to improve the condition of the sludge dewatering truck loadout. The sludge cake silos and truck loading

Final – May 9, 2017 ES‐5 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District facility was last evaluated for capacity under P2‐92, the centrifuge dewatering project which is currently under construction. Though no expansion is recommended under this masterplan, some rehabilitation is still required based on the aging condition of the facility. OCSD has performed an internal condition assessment to determine necessary rehabilitation of the facility.

Section 7 (Implementation Schedule and Sequencing)

In order to ensure continued operation of all of OCSD’s major facilities, the BV/BC Team provided information regarding logical construction sequencing of the projects associated with the Plant No. 2 CIP. This section describes the overall schedule, along with critical path items and sequencing of major construction as summarized below in Figure ES‐3.

Figure ES‐3. A Summary of the Implementation Schedule

Section 8 (Program Costs)

CIP projects were scoped in Task 4; under Task 6, these have been developed into discrete projects for CIP planning purposes. Details of major equipment, process location, and estimated cost are provided in this section for each project identified in Sections 2 and 3.

Final – May 9, 2017 ES‐6 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Table ES‐1. Estimate of Probable Construction Cost for Proposed Plant No. 2 Biosolids CIP (Cost Estimate Basis: December 2016 dollars, unless specified below)

BMP PROJECT CONSTRUCTION COST ESTIMATE (MILLIONS) PROJECT NAME NUMBER LOW (‐30%) MID HIGH (+50%) P2‐500 Interim Digester Repairs $22.9 $32.7 $49.1 P2‐501 Perimeter Screening $0.9 $1.3 $2.0 P2‐502 Interim Pre‐Processed SSO $1.8 $2.6 $3.9 Facility P2‐503 Relocate Warehouse and $3.6 $5.2 $7.8 Collections Yard J‐1241 Digester Gas Handling Facilities $16.5 $23.5 $35.3 X‐0322 Dewatered Sludge Storage and $1.8 $2.5 $3.8 Truck Loading Rehabilitation P2‐504 TPAD Project $107.9 $154.1 $231.2 P2‐504A Class A Batch Tanks $18.4 $26.3 $39.5 P2‐504B Digester Feed Facility $8.8 $12.6 $18.9 P2‐504C Relocate Ferric Chloride Facility $1.0 $1.4 $2.1 P2‐505 Replace Digesters P,Q, R, and S $39.8 $56.8 $85.2 P2‐506 Ultimate Pre‐Processed SSO $4.1 $5.9 $8.9 Facility P2‐507 Replace Digester‐Holders $27.5 $39.3 $59.0 (Formerly I, J, and K) P2‐508 Digester Demolition $5.2 $7.4 $11.1 ALL TOTAL CIP $260.2 $371.6 $557.8 Notes: 1 Estimates are based on February 2015; 2 Estimates are based on February 2016

Final – May 9, 2017 ES‐7 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

1.0 Introduction Orange County Sanitation District (OCSD) is implementing Project PS15‐01, Biosolids Master Plan (BMP), to provide a roadmap and framework for sustainable and cost‐effective biosolids management options. OCSD authorized Black & Veatch Corporation and its teaming partner Brown and Caldwell (BV/BC Team) to develop a BMP report to evaluate existing OCSD solids handling facilities, study solids treatment alternatives, and recommend future capital facilities improvements. The BMP report will be composed of eight technical memoranda and supporting information. This document presents Technical Memorandum (TM) 6: CIP (Capital Improvement Program) Project Development for Plant No. 2 Solids Handling Facilities. 1.1 PURPOSE OCSD had previously identified the need to perform process equipment and structural rehabilitation on the aging 18 digesters to maintain reliable operation of digesters at Plant No. 2. OCSD has had concerns with the structural deterioration of the digester domes, as the digesters date back from 1959 through 1979 and were constructed either without protective liners or liners with failure history. Anticipating the need for structural improvements, including dome replacements for multiple digesters, OCSD embarked on a structural/seismic hazard evaluation study.

Through a condition assessment on project P2‐91 and subsequent condition assessment activities, OCSD identified that the digesters at Plant No. 2 were in need of significant rehabilitation. Prior to commencing the rehabilitation projects, OCSD initiated a study (SP‐186), liquefaction and structural deficiencies were identified as the seismic hazards relating to the existing infrastructure, and a seismic event could lead to several inches of settlement and structural failure for several digesters. The study also evaluated and compared the cost associated with rehabilitating versus constructing new digesters to mitigate these seismic risks. Higher costs were expected for in‐situ soil improvements of the existing structures as compared with greenfield soil improvements through deep soil mixing and re‐construction of the digestion structures. As a result of this study, OCSD selected to replace the existing digesters and associated facilities. The purpose of PS15‐01 is to evaluate and select the future digestion process and associated new infrastructure to replace the existing facilities. 1.2 APPROACH This TM is preceded by and references content in five TMs: TM‐1 OCSD Solids Facilities Summary and Design Basis, TM‐2 Review OCSD’s Biosolids Program and Summarize the Current State, Trends, and Outlook for Biosolids Management, TM‐3 Biosolids Management Alternatives Evaluation, TM‐4 Digestion and Post Dewatering Technologies Evaluation, and TM‐5 High Strength Organic Waste Co‐ digestion Evaluation. Information regarding projected biosolids quantities is contained in TM‐1. Detailed information regarding OCSD’s current biosolids program is contained in TM‐2; the first two TMs form the project basis (see Figure 1‐1, below). TM‐3 and TM‐4 summarize the decision‐ making framework that led to the selection of the core solids treatment technologies detailed in this TM. TM‐5 evaluated the possibility of co‐digestion at Plant No. 2, details of which were further explored under this current task.

Final – May 9, 2017 1‐1 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Figure 1‐1. Task Flow for BMP

Under the guidelines and principles established from OCSD’s 2003 Long‐Range Biosolids Management Plan (LRBMP) and current Biosolids Policy, OCSD designed its biosolids management program to be flexible and sustainable. Task 3 re‐evaluated the OCSD biosolids management program, including investigation into both new and existing end products. Based on the results of the previously conducted biosolids market study and analysis and the efforts documents in TM‐3, a list of biosolids products and markets that would help support its programmatic goals for biosolids have been developed. Under Task 4, the BV/BC Team identified the biosolids technologies available to generate the desired products. These technologies were evaluated and screened in order to identify the best value project to implement at OCSD’s Plant No. 2. Task 6, discussed in this TM, further developed the projects identified under Task 4 for inclusion in OCSD’s capital planning efforts.

This TM covers the following topics:  Description of identified projects to be included with OCSD’s Plant No. 2 solids capital improvements plan.  Description of current Plant No. 2 solids capital improvement projects and a description of recommended modifications to these projects.  Implementation schedule for major Plant No. 2 solids capital improvement projects.  Construction cost estimates and implementation schedule for proposed project(s).

Final – May 9, 2017 1‐2 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

2.0 Background This section summarizes the relevant findings and recommendations of the five previous TMs. In particular, this includes:  Solids Flows and Loads  Design Criteria  TM‐4 Digestion and Post Dewatering Technologies Evaluation Recommendations  TM‐5 High Strength Organic Waste Co‐Digestion Evaluation Recommendations  Geotechnical Evaluations 2.1 SUMMARY OF TM‐4 FINDINGS TM‐4 presents the major elements of work involving the identification and assessment of on‐site biosolids treatment alternatives. A wide range of process technologies were evaluated through a series of end‐to‐end alternatives based on both cost and non‐cost criteria to develop solids process recommendations for Plant No. 2. The following process recommendations were developed from this assessment:  The existing DAFT thickening process is retained for future operation.  Six new thermophilic capable anaerobic digesters should be constructed.  Design and operation will be based on Temperature Phased Anaerobic Digestion (TPAD) process, but flexibility will be included to operate as Conventional Mesophilic Anaerobic Digestion (CMAD) process.  Centrifuge dewatering (currently under construction) would provide dewatering and loadout of digested solids.

The primary recommendation of Task 4 was the conclusion to install six new thermophilic capable digesters and base the initial design around TPAD. The installation of six new thermophilic capable digesters gives OCSD the ultimate flexibility at Plant No. 2 for solids process capacity. Six new digesters would allow operation of any future digestion process, including mesophilic, thermophilic, TPAD, and thermal hydrolysis process. Should OCSD’s project process requirements change in the future, this design approach would allow adaptation of the solids process to meet these future needs. Finally, the initial design approach around TPAD most effectively meets OCSD’s decision making criteria, in particular as a cost effective and quick approach to mitigate the current seismic risks at the plant and to allow opportunities for Class A biosolids production. 2.2 SUMMARY OF TM‐5 FINDINGS TM‐5 presents the feasibility and economic justification for pre‐processed SSO co‐digestion at Plant No. 2. The regulations and other market drivers around pre‐processed SSO co‐digestion were assessed, and it was identified that regulations, in particular AB 1826, related to diversion of pre‐ processed SSO away from landfills was increasing the market demand for co‐digestion. The sources and characteristics for pre‐processed SSO were identified in the surrounding areas near Orange County, and this information was used to develop an economic assessment of pre‐processed SSO

Final – May 9, 2017 2‐1 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District co‐digestion at Plant Nos. 1 and 2. Based on this assessment, the following process recommendations were developed from this assessment:

 Plant No. 1 does not have excess digestion capacity for co‐digestion.  Plant No. 2, with either TPAD or CMAD operation, has excess capacity for co‐digestion.  Financial justification exists to pursue a co‐digestion program at Plant No. 2, with a receiving facility located at the site.  Given that the new digester construction at Plant No. 2 is not planned until 2028, OCSD could decide to build a smaller, interim receiving facility at Plant No.2 to receive pre‐ processed SSO in the near‐term to help meet demand for SSO processing resulting from AB 1826.  Based on excess digester capacity available from now until 2035, the following table summarizes the capacity of pre‐processed SSO that can be co‐digested at Plant No. 2.

Table 2‐1. Pre‐Processed SSO Co‐Digestion Capacity PRE‐PROCESSED SSO CO‐ PERIOD YEARS DIGESTION CAPACITY WET TONS PER DAY)1 Interim 2018‐2028 137 to 580

After TPAD Construction 2028‐2045 320 to 810

Note: 1. Pre‐processed SSO assumed a 12% TS and 85% VS. Pre‐processed SSO co‐digestion capacity depends on solids flows and loads into the digesters. Higher solids flows and loads would result in less capacity.

2.3 GEOTECHNICAL EVALUATION OF PROPOSED FACILITIES Under a previous study (SP‐186), geotechnical exploration and analysis, as well as structural analysis of the Plant No. 2 digester site was developed for potential seismic risks due to known liquefaction risks at the Plant No. 2 site. The SP‐186 Study identified liquefaction and structural deficiencies as the primary seismic hazard that would lead to several inches of settlement and structural failure for several digesters. Ground and structural improvements were identified as one potential mitigation method of the seismic risks. In‐situ improvements included jet grouting ringwall foundations at the digesters and pump rooms, and inserting compaction grouting beneath digester slabs. It was also recommended that tunnels include flexible utility connections at the digester interfaces to mitigate differential settlement as a result of liquefaction. The study also evaluated and compared the cost associated with rehabilitating versus constructing new digesters to mitigate these seismic risks. For new digesters it was assumed that new digesters would be supported on shallow foundation systems with ground‐improved soils through deep soil mixing. The results of this study was an OCSD decision to construct new digesters, driven by the higher cost associated with the in‐situ soil improvements as compared with greenfield soil improvements through deep soil mixing.

Final – May 9, 2017 2‐2 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

A fault study was not part of the scope of the geotechnical study in SP‐186; however, review of previous studies identified multiple splays of the Newport‐Inglewood fault zone running through the existing digester complex. These faults were shown conceptually in SP‐186 (Figure 2‐1). Further studies were recommended to evaluate relative activity and location of these faults.

Figure 2‐1. Projections of the Newport‐Inglewood Fault Zone

Under Task 6.1 of the BMP, a geotechnical study was performed by Kleinfelder Inc. to determine relative activity and location of the faults, suitability for construction, and recommend ground improvement recommendations, as needed. The fault activity and locations were evaluated using existing published and unpublished geologic data as well as field exploration including Cone Penetration Testing (CPT).

The CPT testing was broken into three phases. Phase 1 consisted of 53 CPT tests around the perimeter of the digester area and the northeast boundary of the plant. Phase 2 included 20 CPT tests where faulting was suspected in order to assess the fault trend across the site. Phase 3 consisted of 7 CPT tests that more narrowly defined the fault and further delineated the westernmost extent of the faults identified during the first two phases. The CPT testing and resulting active fault locations are provided in Figure 2‐2.

Final – May 9, 2017 2‐3 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Figure 2‐2. CPT Testing Locations from Kleinfelder Geotechnical Investigation

The results of 80 total CPT tests identified two active faults within the existing and proposed digester complex area. Figure 2‐3 depicts the active fault zone areas in red with a 25‐foot structural setback zone. The setback zone indicates a no‐build zone for either habitable or critical structures and is intended to provide an additional safety buffer. Copies of the Fault Hazard Study and the Geotechnical Feasibility Report can be found in Appendix A and Appendix B, respectively.

Final – May 9, 2017 2‐4 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

3.0 Process Requirements for Future Digestion and Pre‐ Processed SSO Co‐Digestion Facilities This section summarizes the process requirements and performance for the future digestion and pre‐processed SSO co‐digestion facilities based on the recommendations of TM‐4 and TM‐5. 3.1 SOLIDS FLOWS AND LOADS TM‐1 outlined three future solids flow and load conditions. Design of the Plant No. 2 solids handling facility was based on the solids flows and loads produced from the Plant No. 2 secondary process, assuming the secondary process is operated at its design capacity. This scenario represents the maximum solids loading condition, and in order to prevent the solids process capacity from limiting the flows the plant can treat, Condition 3 was used for solids process sizing. Condition 3 assumes that the solids flows and loads produced from Plant No 2 are at their design capacity. It represents the maximum solids loading condition. Table 3‐1 summarizes the digester feed solids flows and loads used for digester design.

Table 3‐1. Plant No. 2 Recommended 2035 Design Loadings for New Digesters under Max 15‐Day Condition DIGESTER FEED PARAMETER UNIT SLUDGE Sludge TS ppd 478,000 Sludge TS % 4.7 Sludge Flow gpd 1,220,000 Sludge VS % of TS 76.5 Sludge VS ppd 366,000

3.2 PRE‐PROCESSED SSO LOADS TM‐5 evaluated the capacity and economic feasibility of pre‐processed SSO receiving at Plant No. 2. As documented in TM‐5, Plant No. 2 has firm capacity for pre‐processed SSO digestion. Plant No.2 digesters could accept 137 to 582 wet tons per day (wtpd) of pre‐processed SSO in 2028 with existing digesters, based on digester capacity for Conditions 2 and 1, respectively. Following the construction of six 110‐ft diameter thermophilic digesters and operation in TPAD (anticipated at the end of 2028), the capacity of the pre‐processed SSO receiving capacity would increase to 320 to 810 wtpd of pre‐processed SSO. Table 3‐2 summarizes the capacity ranges for both time periods described above.

Table 3‐2. Pre‐Processed SSO Co‐Digestion Capacity PRE‐PROCESSED SSO CO‐ PERIOD YEARS DIGESTION CAPACITY (WET TONS PER DAY)1 Interim 2018‐2028 140 to 580 After TPAD Construction 2028‐2045 320 to 810 Note: 1. Pre‐processed SSO at 12% TS and 85% VS. Pre‐processed SSO co‐digestion capacity depends on solids flows and loads. Higher solids flows and loads would result in less capacity.

Final – May 9, 2017 3‐1 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

3.3 DESIGN CRITERIA The design criteria for the selected digestion processes reflects conventional industry experience and specific OCSD experience (Table 3‐3). As documented in TM‐4, these criteria were identified and selected for implementation for the future digestion process.

Table 3‐3. Digestion Design Criteria

DIGESTION DESIGN PARAMETER TYPICAL CONDITION 1 SERVICE CONDITION 2

Units OLR, lb/cf‐day HRT, days OLR, lb/cf‐day HRT, days Temperature Thermo Phase 0.35 9 0.35 8 Phased (TPAD)3 Meso Phase n/a 8 n/a 7 Notes: 1. One thermophilic digester out of service at peak 15‐day loads, assumes all mesophilic digesters in service. 2. Two thermophilic digesters and one large mesophilic digester out of service at peak 15‐day loads. 3. Class B process, Batch Tanks required to go to Class A.

These criteria are to meet the 15‐day HRT requirement for Class B biosolids without the Class A batch tanks. Batch tanks can be added to meet the time and temperature requirements for Class A biosolids (batch tanks shall be sized to provide at least 24 hours holding time at 55 oC). Approaching the design of the digestion process to accommodate either Class A or B operation provides greater reliability and redundancy for future operation.

Based on the solids flows and loads presented in TM‐1, Condition 3 assumes that the solids flows and loads produced from Plant No. 2 are at their design capacity. It represents the maximum solids loading condition. Table 3‐1 summarizes the digester feed solids flows and loads used for digester design.

Based on Table 3‐1 and design criteria presented in Table 3‐3, the digester volumes were developed for the future Plant No. 2 digesters, as shown in Table 3‐4.

Table 3‐4. Digester Volumes

DIGESTER NUMBER DIAMETER SIDE WATER DEPTH ACTIVE VOLUME1

Thermophilic Phase2 110‐ft Diameter 6 110‐ft 32 2.27 Mgal Mesophilic Phase 105‐ft Diameter 4 105‐ft 32 2.07 Mgal 80‐ft Diameter 2 80‐ft 32 1.20 Mgal Holder 1 80‐ft 32 1.20 Mgal Notes: 1. Active volume does not include digester cone. 2. Thermophilic digesters are designed for thermophilic or mesophilic temperatures to provide flexibility to operate as TPAD or CMAD.

Final – May 9, 2017 3‐2 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

The recommendation for the 80‐ft diameter digesters is to be designed to operate as holders, if desired by OCSD staff. Likewise, the holder should be designed to operate as a mesophilic digester. This practice is currently employed at Plant No. 2, and it is recommended that this flexibility be provided with the new digesters/holder. 3.4 PROCESS PERFORMANCE This section discusses the digester performance and digester gas productions under various solids and pre‐processed SSO flows and loads at Plant No. 2.

3.4.1 Digester Performance As discussed in TM‐5, projected future solids productions at Plant No. 2 vary depending on the influent flow split between Plant No.1 and Plant No. 2. TM‐5 recommends the capacity of the interim receiving facility to be 250 wtpd and the initial contract to be 150 wtpd of pre‐processed SSO. Digester operating conditions for the interim facility in 2028 based on 150 to 250 wtpd of pre‐ processed SSO are summarized in Table 3‐5. Detailed calculations are shown in Appendix H.1

Table 3‐5. Summary of Digester Operating Conditions for the Interim Facility in 2028 with Pre‐Processed SSO1 TYPICAL SERVICE PARAMETER UNIT CONDITION2 CONDITION3 Total Active Digester Capacity MG 17.9 16.8 HRT Day 23 21 Condition 14 OLR lb VS/cf 0.11 0.12 HRT Day 18 17 Condition 25 OLR lb VS/cf 0.13 0.14 Notes: 1. Refer to Appendix H.1 for detailed calculations. 2. One large digester out of service at peak 15‐day loads. 3. Two large and one small digesters out of service at peak 15‐day loads. 4. Condition 1 solids flows and loads with 250 wtpd pre‐processed SSO. 5. Condition 2 solids flows and loads with 150 wtpd pre‐processed SSO.

Once the new digesters are on‐line and operate in TPAD, more pre‐processed SSO can be received for co‐digestion. TM‐5 estimates that the amount of pre‐processed SSO can be received for co‐ digestion ranges from 320 to 810 wtpd, and recommend the capacity of the ultimate receiving facility to be 500 wtpd. Digester operating conditions in 2045 based on 320 to 500 wtpd of pre‐ processed SSO for the TPAD operation are summarized in Table 3‐6. Detailed calculations are shown in Appendix H.2.

Final – May 9, 2017 3‐3 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Table 3‐6. Summary of Digester Operating Conditions for TPAD Operation in 2045 with Pre‐processed SSO1 TYPICAL SERVICE PARAMETER UNIT CONDITION2 CONDITION3 Thermophilic Phase Digesters Total Active Digester Capacity MG 11.4 9.1 HRT Day 12 10

4 Condition 1 OLR lb VS/cf 0.24 0.30

HRT Day 10 8 Condition 25 OLR lb VS/cf 0.26 0.32

Mesophilic Phase Digesters

Total Active Digester Capacity MG 10.7 8.6 Condition 14 HRT Day 11 9 Condition 25 HRT Day 9 8 Total HRT Condition 14 HRT Day 23 19 Condition 25 HRT Day 19 16 Notes: 1. Refer to Appendix H.2 for detailed calculations. 2. One thermophilic digester out of service at peak 15‐day loads. 3. Two thermophilic digesters and one large mesophilic digester out of service at peak 15‐day loads. 4. Condition 1 solids flows and loads with 500 wtpd pre‐processed SSO. 5. Condition 2 solids flows and loads with 320 wtpd pre‐processed SSO.

3.4.2 Digester Gas Production Digester gas productions from Plant No.2 were estimated and presented in this section. The gas productions were then used to evaluate the capacity of gas handling facilities, which are presented in Section 4.2.10.

Digester gas production varies depending on solids flows and loads as well as the amount of pre‐ processed SSO for co‐digestion. Since the pre‐processed SSO is more easily digestable and has higher VS content than solids, more digester gas can be produced from pre‐processed SSO than solids in the same volume. For this reason, the digester gas productions are presented in two sets of values for Plant No. 2. Digester gas productions at Plant No. 2 for the interim facility and the ultimate facility are shown in Table 3‐7 and Table 3‐8, respectively. Detailed calculations are shown in Appendix H.1 and Appendix H.2.

Final – May 9, 2017 3‐4 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Table 3‐7. Plant No. 2 TPAD Digester Gas Productions with the Interim Facility in 2028, scfm1,2 RESIDUAL TO PARAMETER Condition 13, scfm Condition 24 scfm DIGESTION , Annual Sludge 1,080 1,440 Average SSO 425 230 Combined 1,510 1,670 Peak 15‐Day Sludge 1,300 1,720 SSO 425 230 Combined 1,730 1,950 Peak Hour5 Sludge 1,620 2,150 SSO 640 350 Combined 2,260 2,500 Notes: 1. Refer to Appendix H.1 for detailed calculations. 2. Sludge VSR=57%, SSO VSR =80%, gas production rate = 15 cf/lb VSR. 3. Condition 1 solids flows and loads and 500 wtpd pre‐processed SSO. 4. Condition 2 solids flows and loads and 320 wtpd pre‐processed SSO. 5. Peak hour gas flow equals 1.5 times annual average gas flow.

Table 3‐8. Plant No. 2 TPAD Digester Gas Productions with the Ultimate Facility in 2045, scfm1,2 RESIDUAL TO PARAMETER Condition 13, scfm Condition 24 scfm DIGESTION , Annual Sludge 1,380 1,720 Average SSO 850 540 Combined 2,230 2,260 Peak 15‐Day Sludge 1,660 2,070 SSO 850 540 Combined 2,510 2,610 Peak Hour5 Sludge 2,070 2,580 SSO 1,280 810 Combined 3,350 3,390 Notes: 1. Refer to Appendix H.2 for detailed calculations. 2. Sludge VSR=61%, SSO VSR =80%, gas production rate = 15 cf/lb VSR. 3. Condition 1 solids flows and loads and 500 wtpd pre‐processed SSO. 4. Condition 2 solids flows and loads and 320 wtpd pre‐processed SSO. 5. Peak hour gas flow equals 1.5 times annual average gas flow.

It is worth noting that at thermophilic temperatures, greater quantities of moisture should be present in the digester gas. This will need to be considered in the design of the digester gas

Final – May 9, 2017 3‐5 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District handling systems, including the waste gas flares, gas conditioning and compression system for CenGen, and steam boiler gas conditioning systems for process heating.

Digester gas productions at Plant No. 1 are also included in Table 3‐9 for CenGen capacity valuation. Detailed calculations are shown in Appendix H.3. Gas productions at Plant No. 1 were based on high solids flows and loads condition to Plant No. 1 documented in TM‐1, which represents a high digester gas production condition and is conservative for gas handling system design. As discussed in TM‐5, there is no excess digester capacity at Plant No. 1 for co‐digestion. Therefore, gas productions are from sludge.

Table 3‐9. Plant No. 1 Digester Gas Productions in 2045, scfm1,2

PARAMETER CONDITION 13 CONDITION 24 Annual 1,840 1,470 Average Peak 2,210 1,770 15‐Day Peak Hour5 2,760 2,200 Notes: 1. Refer to Appendix H.3 for detailed calculations. 2. Sludge VSR=57%, gas production rate = 15 cf/lb VSR. 3. Condition 1 solids flows and loads. 4. Condition 2 solids flows and loads. 5. Peak hour gas flow equals 1.5 times annual average gas flow.

3.5 PROCESS HEAT DEMAND Support of the future digestion process would require increased process heat demand. Table 3‐10 summarizes the maximum heat demand, expressed as million British thermal units per hour (MMBTUh) of heat, for both CMAD and TPAD and the existing process heat capacity from Central Power Generation Systems (CenGen) and steam boilers.

Table 3‐10. Digester Heat Demand and Capacity of Existing Heat Recovery Equipment in 2035 MAX. HEATING TOTAL HEATING CAPACITY TOTAL HEATING CAPACITY PROCESS REQUIREMENT FROM CENGEN FROM EXISTING BOILERS (MMBTUh) (MMBTUh) (MMBTUh) CMAD 15.01 27.81 16.74 TPAD 30.73 27.81 16.74

Heat recovery from CenGen would, in most cases, provide sufficient heat for process heating needs. If additional process heat is required, digester gas should be used in the boilers to produce additional heat as the boilers can generate more efficient heat recovery than the CenGen heat recovery system. If CenGen is out of service, it is recommended that sufficient boiler capacity is available to meet the peak process heat demand. To provide this ability, additional boilers are required.

Final – May 9, 2017 3‐6 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

4.0 Conceptual Design for Future Digestion and Pre‐ Processed SSO Co‐Digestion Facilities The recommendations of TM‐4 and TM‐5 outline the fundamental framework of the future solids handling facilities at Plant No. 2, and implementation of these recommendations would dictate the development of the Plant No 2 CIP schedule and budget. This section summarizes the conceptual design for the future digestion and pre‐processed SSO co‐digestion facilities based on the recommendations of TM‐4 and TM‐5. 4.1 PROCESS FLOW DIAGRAM The process flow diagram outlines the primary processes and process flow required for TPAD operation. In addition to the facilities associated with each process, there are several ancillary facilities. Figure 4‐1 provides an overview of the TPAD process flow, which is also presented in Appendix J (enclosed Flash Drive) along with a detailed equipment list, which includes motor sizes. Appendix J is also published as a hard copy at the end of TM‐6.

Primary TPAD processes include:  Anaerobic Digesters o Six thermophilic digesters o Six mesophilic digesters o Two mesophilic holders  Class A batch tanks  Digester feed facility  TPAD Sludge Cooling Ancillary TPAD facilities include:  Interim and Ultimate pre‐processed SSO receiving facilities  Digester gas handling  Ferric chloride feed

Final – May 9, 2017 4‐1 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Figure 4‐1. Overall TPAD Solids Process Flow Diagram

4.2 PROCESS DESIGN The primary and ancillary process for TPAD are described in more detail in this section.

4.2.1 Thermophilic Digesters (110‐ft Diameter) The thermophilic digestion phase of TPAD requires six new thermophilic digesters with an inner diameter of 110‐feet.

4.2.1.1 Description The number of new tanks required was designed based on the design criteria shown in Table 3‐3. The digester geometry was designed to match the geometry of the existing digesters P, Q, R, and S with the exception of a greater diameter tank and height to providing additional capacity and reduce total number of tanks required. Each digester is cylindrical in shape with a top dome and conical shaped bottom.

Prioritizing the construction of the six thermophilic digesters mitigates seismic and operational risks because the six thermophilic digesters are capable of processing all of Plant No. 2’s solids in the event of a catastrophic failure of the existing mesophilic digesters (e.g. seismic event, structural

Final – May 9, 2017 4‐2 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities failure). The resulting biosolids can be hauled to regional composting or landfill, if sub Class B, or hauled to land application in Arizona or regional composting, if Class B product.

4.2.1.2 Major Equipment List Major equipment to be included under this project is summarized in Table 4‐1.

Table 4‐1. A Summary of the Major Equipment Required for this Project PROJECT COMPONENT QTY. NOTES 110’ Diameter Digester 6 2.27 MG (13.62MG total), thermophilic Thermophilic Digester Feed Pumps, 12 280 gpm at 100 psi, 40 HP (5 Duty, 7 Standby) Progressive Cavity Thermophilic Digester Mixing 12 7,800 gpm at 25ft, 100 HP (5 Duty, 7 Standby) Pumps, Chopper Pumps Thermophilic Digester Grinders, 12 450 gpm, 5 HP (10 Duty, 2 Standby) Inline Thermophilic Digester Circulation 15 450 gpm at 45ft,10 HP (10 Duty, 5 Standby) Pumps, Screw Centrifugal Thermophilic Digester HEX, 12 450 gpm, 7.65 MMBTUh (10 Duty, 2 Standby) Concentric Tube Thermophilic Digester Transfer 12 280 gpm at 100 psi, 40 HP (5 Duty, 7 Standby) Pumps, Progressive Cavity

4.2.1.3 Facility Layout The digesters should be configured to share an interior space for the digester equipment gallery. The recommendation is to space the digesters to allow truck access to the equipment gallery for equipment access. Tunnel access should be provided for equipment maintenance access. Equipment for each digester would be in the equipment gallery floors as shown in Figures 4‐2 and 4‐3, below.

Final – May 9, 2017 4‐3 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Figure 4‐2. Thermophilic Equipment Gallery Layout at Grade

Final – May 9, 2017 4‐4 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Figure 4‐3. Thermophilic Equipment Gallery Layout below Grade

The equipment gallery includes two floors. The grade level includes the digester heat exchangers (HEX), standpipes and U‐tube assemblies as shown in Figure 4‐2 above. The suggested location for the HEX is adjacent to each digester and spaced to provide truck access to each piece of equipment for maintenance.

The basement level includes the majority of the required equipment including digester feed and transfer pumps, mixing pumps and grinders. The gallery basement level should be designed to allow tunnel access with a truck at three locations as depicted in Figure 4‐3 in purple. Digester drain pumps should be located in sumps below the basement level.

4.2.2 Mesophilic Digesters (105‐ft Diameter) The mesophilic digestion phase of TPAD requires four new mesophilic digesters with an inner diameter of 105‐feet.

4.2.2.1 Description The number of new tanks required was designed based on the design criteria shown in Table 3‐3. The digester geometry was designed to match the geometry of the existing digesters P, Q, R, and S. Each digester is cylindrical in shape with a top dome and conical shaped bottom. Based on design, after the thermophilic digesters are in service, the cooled sludge would be fed to the existing mesophilic digester feed loops (A, B, and C) until the completion of the remaining mesophilic digesters are replaced.

Final – May 9, 2017 4‐5 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

4.2.2.2 Major Equipment List Major equipment included as part of this project is summarized in Table 4‐2.

Table 4‐2. The 105‐ft. Diameter Digester Major Equipment List PROJECT COMPONENT QTY. NOTES 105’ Diameter Digester 4 2.07 MG (8.28MG total), mesophilic Mesophilic Digester Mixing Pumps, 8 7,800 gpm at 25 ft, 100 HP (5 Duty, 7 Standby) Chopper Pumps

Mesophilic Digester Grinders, Inline 6 900 gpm, 5 HP (4 Duty, 2 Standby)

Mesophilic Digester Circulation 6 900 gpm at 35 ft, 15 HP (4 Duty, 2 Standby) Pumps, Screw Centrifugal Mesophilic Digester HEX, Concentric 4 450 gpm, 3.15 MMBTUh (4 Duty, 0 Standby) Tube Mesophilic Digester Transfer Pumps, 8 270 gpm at 100 psi, 25 HP (4 Duty, 4 Standby) Progressive Cavity

4.2.2.3 Facility Layout The 105‐ft diameter digesters are assumed to be rebuilt in place of existing digesters P, Q, R, and S and should follow a similar facility layout. Note that the number and type of equipment included at this level is conservative and requires more space than available in the existing P, Q, R, and S pump room configuration. Additional equipment can be placed outdoors around the .digesters or an expanded pump room could be provided as necessary. Under detailed design, adequate space planning should include provisions for future conversion of this set of mesophilic digesters to thermophilic digesters. Figure 4‐4 illustrates the 105‐ft digester faiclity layout. For planning purposes, a 2.5’ wall thickness is assumed for all digesters as this is a function of sidewater depth and not tank diameter.

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Figure 4‐4. Facility Layout of the 105‐ft Diameter Digesters

4.2.3 Mesophilic Digesters (80‐ft Diameter) The mesophilic digestion phase of TPAD requires two new mesophilic digesters with an inner diameter of 80‐feet.

4.2.3.1 Description The number of new tanks required was designed based on the design criteria shown in Table 3‐3. The digester geometry was designed to match the geometry of existing digesters I, J, and K. Each digester is cylindrical in shape with a top dome and conical shaped bottom.

4.2.3.2 Major Equipment List Major equipment included as part of this project is summarized in Table 4‐3.

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Table 4‐3. Major Equipment List for the 80‐ft Diameter Digesters PROJECT COMPONENT QTY. NOTES 80’ Diameter Digester 2 1.20 MG (2.40 MG total), mesophilic Mesophilic Digester Mixing Pumps, 4 4,700 gpm at 25 ft, 60 HP (2 Duty, 2 Standby) Chopper Pumps Mesophilic Digester Grinders, Inline 3 600 gpm at 5 HP (2 Duty, 1 Standby) Mesophilic Digester Circulation 3 600 gpm at 10 HP (2 Duty, 1 Standby) Pumps, Screw Centrifugal Mesophilic Digester HEX, Concentric 2 600 gpm, 0.92 MMBTUh (2 Duty, 0 Standby) Tube Mesophilic Digester Transfer 4 160 gpm at 25 HP (2 Duty, 2 Standby) Pumps, Progressive Cavity

4.2.3.3 Facility Layout The 80‐ft diameter digesters assume a similar facility layout to digester I and J are recommended, which is shown in Figure 4‐5. Note that the number and type of equipment included at this level is conservative and requires more space than available in the existing I and J pump room configuration. Additional equipment can be placed outdoors around the digesters or an expanded pump room could be provided as necessary. For planning purposes, a 2.5’ wall thickness is assumed for all digesters as this is a function of sidewater depth and not tank diameter.

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Figure 4‐5. Facility Layout of the 85ft Diameter Digesters

4.2.4 Digested Sludge Holders (80‐ft Diameter) The mesophilic digestion phase of TPAD requires two new mesophilic digesters with an inner diameter of 80‐feet.

4.2.4.1 Description Two 80‐ft diameter digesters are designated as digester‐holders capable of operating as digesters when additional HRT or stabilization is required or as holders to provide operational flexibility of the dewatering facilities. In addition to the digesters, one dedicated 80‐ft diameter holder is part of the design to ensure there is always a wide spot between digestion and dewatering. This mirrors the current operation of Digester I, J and Holder K. The digester geometry was designed to match the geometry of the existing digesters I, J, and K. Each digester is cylindrical in shape with a top dome and conical shaped bottom.

4.2.4.2 Major Equipment List Major equipment included as part of this project is summarized in Table 4‐4.

Final – May 9, 2017 4‐9 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Table 4‐4. Summary of the Major Equipment List for the Holders PROJECT COMPONENT QTY. NOTES 80’ Diameter Digested Sludge 1 1.20 MG (2.40 MG total), mesophilic capable Holder Digested Sludge Holder Mixing 2 4,700 gpm at 25 ft, 60 HP (1 Duty, 1 Standby) Pumps, Chopper Pumps Digested Sludge Holder Grinders, 1 600 gpm at 5 HP (0 Duty,1 Standby) Inline Digested Sludge Holder Circulation 1 600 gpm at 10 HP (0 Duty, 1 Standby) Pumps, Screw Centrifugal Digested Sludge Holder HEX, 1 600 gpm, 0.92 MMBTUh (0 Duty, 1 Standby) Concentric Tube Digester Sludge Holder Transfer 3 700 gpm at 100 psi, 75 HP (2 Duty, 1 Standby) Pumps, Progressive Cavity

4.2.4.3 Facility Layout The 80‐ft diameter Digested Sludge Holders assume a similar facility layout to digesters I and are suggested. Note that the number and type of equipment included at this level is conservative and requires more space than available in the existing I and J pump room configuration. Additional equipment can be placed outdoors around the digesters or an expanded pump room could be provided as necessary.

4.2.5 Digester Feed Facility (DFF) A Digester Feed Facility (DFF) would allow for blending of primary sludge, thickened waste activated sludge (TWAS), and potential pre‐processed SSO as well as provide the TPAD process a uniform and constant digester feed.

4.2.5.1 Description The new DFF would replace the existing sludge blending facility (SBF) where primary sludge and scum is blended and fed to the digesters. The new facility would contain two 100,000‐gallon octagonal concrete T‐Lock lined tanks with a side water depth of 29 ft, an electrical and control room, and the various mixing and transfer pumps for operation. Primary sludge along with scum should be pumped directly into this facility from the Primary Clarifiers. However, further evaluation is required to determine whether primary scum would be routed to the DFF or directly into the digesters. TWAS should be pumped from the DAFTs. The two types of sludge would be combined in the tanks and mixed with centrifugal pumps. The blended sludge would then be fed to the digesters using progressing cavity transfer pumps.

Odors can result from storage or thickened raw sludge, especially during warm weather. The foul air from the DFF tanks should be treated by an odor control system. The odor control facility is recommended to be sized to treat 8,000 cfm and consist of two 12 ft diameter bioscrubbers and two 12 ft diameter carbon scrubbers. The carbon scrubbers would operate in a 1‐duty and 1‐standby configuration and act as a polishing step to the bioscrubbers.

Final – May 9, 2017 4‐10 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

4.2.5.2 Major Equipment List Major equipment included as part of this project is summarized in Table 4‐5.

Table 4‐5. The DFF Major Equipment List PROJECT COMPONENT QTY. NOTES TS Tank, T‐lock Lined Concrete 2 100,000 gal (1 Duty, 1 Standby) Thickening Foul Air Fan, FRP 2 5,000 gpm at 5 psi, 20 HP (1 Duty, 1 Standby) Centrifugal TS Tank Grinders, Inline Grinder 4 5,000 gpm, 40 HP (1 Duty, 3 Standby) TS Tank Mixing Pump, Screw 4 4,000 gpm at 20 ft, 40 HP (1 Duty, 3 Standby) Centrifugal TS Tank Transfer Pumps, 6 600 gpm at 100 psi 70 HP (3 Duty, 3 Standby) Progressive Cavity Sump Pumps 2 (1 Duty + 1 Standby) Bioscrubber 2 8,000 cfm (1 Duty + 1 Standby) Carbon Scrubber 2 8,000 cfm (1 Duty + 1 Standby)

4.2.5.3 Facility Layout The digester feed facility houses all mechanical equipment in a common room as shown in Figure 4‐6, below.

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Figure 4‐6. Digester Feed Facility Layout

4.2.6 TPAD Class A Batch Tanks The addition of batch tanks to the digestion system would allow OCSD to generate Class A biosolids at Plant No. 2, providing more flexibility in OCSD’s end use program. Class A cake can be land applied in California or Arizona, used as soil blend, or used for land reclamation/restoration. Diverse end use options support OCSD’s biosolids policy and helps mitigate future economic and/or regulatory risks. Figure 4‐7 illustrates the process flow for TPAD with batch tanks.

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Figure 4‐7. Schematic of Class A TPAD with Batch Tanks

Class A batch tank can produce Class A biosolids per EPA 503 regulations through batch holding over a specified time and temperature. Class A batch tanks are implemented after the thermophilic digestion phase of TPAD to produce Class A biosolids. To meet Class A requirements, the batch tank must operate at a temperature greater than or equal to 131°F (55°C) in a batch holding mode over a period of 24 hours. In addition, the overall TPAD process much maintain a minimum VSR of 38% to meet the EPA 503 vector attraction reduction requirements.

With the addition of Class A batch tanks to TPAD, a Class A product can be generated for beneficial use without the need for further processing. With the construction of six thermophilic digesters and the Class A batch tanks, further risk mitigation of a seismic event is provided. For example, if the mesophilic digesters are rendered inoperable following a seismic event, the six thermophilic digesters and the batch tanks would continue to produce Class A biosolids. The biosolids product may be slightly more odors without the mesophilic polishing stage, but the product can continue to be routed offsite for disposition without significant changes to the biosolids management program.

4.2.6.1 Class A Batch Tank Evaluation and Justification The BV/BC team evaluated the comparative project costs of different TPAD Class B and Class A alternatives using the Solids Water Energy Evaluation Tool (SWEET) to determine if implementation of a Class A program would offset the capital expenditures associated with Class A processing. Details of the SWEET evaluation methodology were described in more detail in TM‐4. Each alternative consisted of TPAD solids processing, and for Class A alternatives, Class A batch tanks were added to produce Class A biosolids. For each alternative, various sub‐alternatives were evaluated for which only the end use programs were varied. Seven different end to end alternatives were considered, and the end use programs associated with these alternatives are presented in Table 4‐6.

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Table 4‐6. A Summary of Biosolids End Use Programs PROGRAM END USE Soil blending Class B Class A Class A Class A Soil Class A Land (small scale Cake Land Cake Land Cake Land Blend (via Name Composting Reclamation on‐site or in Application, Application, Application, third party Facility /Restoration partnership) Arizona Arizona California contractor) TPAD 50% 50% Class B 100% Land 50% 50% Application All California 5% 70% 25% End Use Aggressive Soil Blend 5% 40% 5% 50%

Program Moderate Soil Blend 5% 40% 20% 25% 10%

Program Diverse 35% 15% 25% 25% Program #1 Diverse 30% 30% 30% 10% Program #2

The associated disposition costs for each end use program are provided below in Table 4‐7.

Table 4‐7. End Use Unit Cost END USE OPTION $/WET TON Onsite Soil Blend $30.00 Offsite Soil Blend $30.00 Land Reclamation/Restoration $47.00 Land Application, Arizona $55.00 Land Application, California $47.00 Class A Composting Facility $56.00

Results of this Class B vs Class A analysis are presented in Figure 4‐8, summarizing capital and operating costs and the net present value (NPV). Results indicate that the majority of Class A alternatives (except 100% Class A land application) had a lower NPV than the Class B alternative. These results would imply that the more diverse end use program provided by Class A processes would allow opportunities to recover the capital and operating costs associated with the Class A batch tanks.

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$800

$700

$600

$500

$400 $Millions $300

$200

$100

$0 TPAD Class B 100% Land All California Aggressive Moderate Soil Diverse Diverse Application End Use Soil Blend Blend Program #1 Program #2 Program Program

Capital Cost O&M NPV

Figure 4‐8. The Net Present Value of Class B Versus Class A

The resulting NPVs indicated that the two highest cost programs were also the least diverse: Class B at $742M and 100% Class A land application at $748M. The lowest NPV involved Class A soil blending program. Based on this analysis, Class A batch tanks were selected by OCSD in Workshop 6.1.2 for implementation with the Plant No. 2 CIP.

4.2.6.2 Reactivation and Regrowth Potential with Class A Testing for indicator organisms, such as fecal coliform and Salmonella, is commonly used as a surrogate for the presence of pathogen in biosolids. In the early 2000s, some utilities reported substantial increases in the densities of indicator organisms following dewatering with high‐solids centrifuges. In 2006, the Water Environment Research Foundation (WERF) funded initial research to investigate observations of regrowth of fecal coliforms in centrifuge dewatered biosolids (Higgins 2006a). Of seven facilities from which biosolids cake was sampled, four indicated signs of possible bacterial reactivation and suggested that high solids centrifuges might be the culprit. Due to the small sample size, no statistically significant conclusions could be drawn, but suggested that it was possible that thermophilic treatment caused bacteria to enter a non‐culturable state, but could be “reactivated” during storage. Once reactivated, the biosolids could experience “regrowth” of these reactivated bacteria, triggering an increase in indicator organism levels. The phenomenon of regrowth was considered separate from the phenomenon of sudden increase of bacteria (increase in densities by as much as 10,000 times). Subsequent research funded by WERF

Final – May 9, 2017 4‐15 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District proposed that the enumeration of fecal coliform post‐digestion, using the standard EPA methodology, was not accurate, and that the dewatering processes changed conditions such that bacteria were culturable. Thus, the phenomenon of sudden increase was an enumeration error, and principally related to fecal coliform and Escherichia coli (though not Salmonella), not necessarily the pathogens themselves. In other words, while conformance to the time‐temperature regime specified by 40 CFR 503 might be adequate for inactivating actual pathogens, such as Salmonella, it might not be adequate for indicator organisms like fecal coliform, which may enter a non‐culturable state. Generally speaking, significant increase was not observed for mesophilically digested biosolids.

The WERF researchers postulated that the reactivation mechanism was particular to high solids dewatering because centrifuge dewatering allowed for the release of proteins and other bioavailable substrates that enhanced bacterial growth as well as the formation of odorous by‐ products (Higgins 2006, 2008). Subsequent research evaluated the effects of wastewater treatment processes on odors, significant increase, and regrowth (Higgins 2015). OCSD was an active participant in the Technical Advisory Committee for this final phase of research. The 2015 research had several findings with respect to both odors and regrowth:

 For mesophilically digested biosolids, odor production generally spiked within the first 24 hours and then rapidly dropped off. Persistent odor compounds tended to develop after storage times of 20‐30 days and again dropped off after about 100 days of storage.  A single TPAD facility was evaluated with two digesters in series. This facility did seem to show signs of sudden increase following centrifuge dewatering.  Odors from mesophilic digestion were generally comparable to that of the TPAD plant sampled.  In general, better digestion yields a lower odor cake.

Parallel research conducted at the University of Arizona has shown that at land application sites, the risk from regrowth tends to be low (Zaleski et al. 2005, Gerba et al. 2008). Land application practices, such as rapid incorporation, can help with mitigating regrowth/promoting bacterial die‐ off. Introduction of moisture, such as rain on field stored piles, can allow for regrowth.

While the mechanisms for reactivation and regrowth are now generally understood, and it is believed that the Class B site restrictions are protective of public health even when regrowth is experienced, the data for TPAD is extremely limited and no quantitative conclusions can be drawn as to the impact of centrifuge dewatering on TPAD digested biosolids. OCSD may wish to collaborate with others pursuing TPAD, such as San Francisco and San Jose, to evaluate best practices for TPAD digestion systems.

4.2.6.3 Class A Batch Tank Number and Sizing The batch tanks were designed for a fill/hold/draw mode of operation. In this mode, tanks would be either filling, holding for 24 hours, or drawings to the mesophilic digesters, thus allowing constant flow of digested sludge. Figure 4‐9 depicts the flow of the fill/hold/draw sequence.

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Figure 4‐9. Class A Batch Tank Fill ‐ Hold ‐ Draw Flow Schematic

4.2.6.4 Description The TPAD batch tanks are designed with six holding tanks to provide a fill/hold/draw mode of operation. The tanks are sized at 400,000 gal, each, to meet peak day flows with all tanks in service and peak 15‐day flows with three units in service. This approach will allow unit to be taken out of service under all conditions except peak day. The tanks are suggested to be square with a width of 41 feet and sloped bottoms. Five of the tanks would be in service, operating in a fill‐hold‐draw sequence. One tank would fill, three would be holding, while the fifth tank would be in withdraw mode. Each tank would have dedicated mixing and heat exchangers to maintain thermophilic temperatures.

4.2.6.5 Facility Process Flow Diagram Figure 4‐10 is a schematic of the Class A batch tanks.

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Figure 4‐10. Class A Batch Tank Schematic

4.2.6.6 Major Equipment List Table 4‐8 summarizes the major equipment required for the new batch tanks and their operation.

Table 4‐8. Major Equipment List Required for Class A Batch Tanks

PROJECT COMPONENT QTY. NOTES

Class A Batch Tanks 6 400,000 GAL each (2.4 MG total), Concrete (5 Duty, 1 Standby) Batch Tank Recirculation Pumps, Screw 6 Centrifugal 500 gpm at 60 ft, 15 HP (4 Duty, 2 Standby)

Batch Tank Heat Exchangers, Spiral 6 500 gpm, 0.36 MMBTUh (4 Duty, 2 Standby), maintaining temperature over 24 hours requires little heat Batch Tank Grinders, Inline 6 500 gpm, 5 HP (4 Duty, 2 Standby) Hot Water Circulation Pump, Horizontal 6 350 gpm at 60 ft, 7.5 HP (4 Duty, 2 Standby) Frame Mounted End Suction Centrifugal

Batch Tank Transfer Pumps, Progressive 4 400 gpm at 100 psi, 50 HP (3 Duty, 1 Standby) Cavity

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4.2.6.7 Facility Layout The six new Class A batch tanks should be constructed where the warehouse is currently located. As open space is limited, the space for the batch tanks would be used by the contractor for staging during construction. In addition to the tanks, two piping and utility tunnels would need to be constructed to connect the digesters to the batch tanks as well as to the secondary effluent sludge cooling system. Figure 4‐11 is a schematic of the batch tank layout.

Figure 4‐11. A Schematic of the Facility Layout for the Batch Tanks

4.2.7 TPAD Sludge Cooling Sludge digested in the TPAD process must be cooled between the thermophilic and mesophilic digestion steps from approximately 131° F to 100° F. Based on the projected peak 7‐day sludge loading and concentration, 14.3 MMBTUh of heat would be removed from the sludge. For this TM, cooling with effluent from the Activated Sludge (AS) Plant was considered. The AS effluent water quality considering the future diversion of non‐reclaimable flows to the AS Plant and was used in this analysis to be conservative. Alternative cooling methods will be discussed briefly at the end of this section.

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Conceptually, sludge cooling with plant effluent is straight‐forward. The AS plant effluent has a temperature of 72 – 86 °F that could be used to cool the hotter sludge via a heat exchanger. In practice, using plant effluent is convoluted by two characteristics of the effluent’s water chemistry.

First, the plant’s AS effluent is corrosive due to its high chloride and sulfate content. The corrosiveness would cause rapid corrosion of carbon steel or stainless steel heat exchangers, therefore a heat exchanger formed of non‐ferrous material, such as titanium, would be required. Plate and frame heat exchangers made of titanium are available, but plate‐and‐frame heat exchangers cannot be used directly with sludge because of its solids content. For sludge cooling, concentric tube heat exchangers or spiral heat exchangers composed of carbon or stainless steel are employed.

Instead of direct sludge‐effluent cooling, an indirect cooling system is necessary to allow two types of heat exchangers to be used – one that comes into contact with the effluent (titanium plate and frame), another that contacts the sludge (carbon steel concentric tube), and an intermediate water loop to transfer heat between the two heat exchanger types. Figure 4‐12 illustrates the sludge cooling process using indirect plant effluent cooling.

Because of the warm temperature of the plant effluent and the requirement for indirect cooling, the heat exchangers would have a large number of tubes or plates. The sludge cooling system would consist of four heat exchangers, each with 52 concentric tubes, 21 feet in length, and three (two duty, one standby) plate‐and‐frame heat exchangers, each with 73 in. x 33 in. frames and 197 plates each.

Figure 4‐12. Process Flow Diagram of Sludge Cooling with Plant Effluent

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Second, the plant’s AS effluent has high levels of hardness. When hard water is heated in a HEX, it forms limescale on the heat transfer surfaces and reduces the heat transfer capacity of the heat exchanger. Given the hardness of the plant effluent, the heat exchangers would likely require frequent cleaning to control limescale.

To mitigate limescaling in the heat exchangers, various design approaches, such as maintaining high velocities and pressure through the heat exchangers, and technologies, such as electronic descalers, were investigated for this application. However, the only way to provide an acceptable level of maintainability and reliability for the sludge cooling system is softening of the plant effluent.

To prevent limescaling in the heat exchangers, the hardness of the water needs to be reduced by at least 50 percent. The plant effluent can be softened in one of three ways: precipitation softening (sometimes referred to as lime softening), cation exchange softening, or ultrafiltration followed by nanofiltration with membranes (UF/NF).

To treat 2,000 gpm of cooling water, precipitation softening would require a tremendous quantity of chemicals, approximately 3.5 tons per day of caustic to raise the pH of the water and precipitate out the calcium carbonate, and 1 ton per day of carbon dioxide to lower the pH and prevent further precipitation. Ferric chloride and polymer dosing would also be necessary to facilitate separation of the precipitates from the water. The process would generate nearly 14 dry tons of chemical sludge per day. The precipitation process would require a 50‐ft diameter solids contact clarifier with a 15‐ ft sidewall depth.

A cation exchange system reduces the water hardness by nearly 100 percent by replacing calcium ions with sodium ions. To reduce the hardness of the 2,000 gpm flow by 50 percent, only about 1,100 gpm of water must be softened, then blended with 1,000 gpm of untreated water. The plant effluent must first be filtered to prevent plugging of the resin beds. The cation exchange system would require about 11 tons per day of salt. It would not produce a chemical sludge, but instead would generate approximately 50,000 gal per day of brine. To process 1,100 gpm would require four 10‐ft diameter by 10‐ft‐tall resin tanks, in addition to brine tanks and water filtration equipment.

A third water softening process is UF/NF membrane filtration. This process filters dissolved chemicals from the water, thereby reducing the hardness. Similar to the cation exchange process, slightly more than half the water would be filtered, then combined with 1,000 gpm of plant effluent to achieve 50% reduction in hardness. The process would generate about 500 gpm of brine and backwash water and require large pumps for pressurizing the water. Chemicals would be necessary for self‐cleaning of the membranes, but not for adjusting the chemistry of the water. The most significant operating expense would be electricity for pumping the water through the filtration system.

While this TM only considers effluent cooling, other cooling methods could be considered during design that may offer a simpler more economical solution. An evaporative cooling tower could use plant effluent, and while it would also need to be treated prior to use, the volume of plant effluent used would be significantly less. A refrigeration chiller is technically feasible as well. An electrically driven refrigeration unit would be very costly to operate, but an absorption chiller may be a satisfactory alternative if there is a source of high‐quality (300° F or more) waste heat. It does not

Final – May 9, 2017 4‐21 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District appear that the plant would have adequate waste heat available at that temperature because heat from the cogeneration engine exhaust is used to drive a steam turbine. Geothermal exchange, in which the heat is dissipated into the ground through buried piping, could be considered as well. Dispensing of the heat from the sludge by air cooling is not feasible for this project because the air temperature at the plant is often too high.

4.2.7.1 Description The pump station would house two secondary effluent cooling pumps in a one duty, one standby operation and have an approximate 1,050 sq. ft footprint. To convey flow from the pump station to the cooling heat exchangers in a loop, approximately 4,200 linear feet of 10 inch lined (anti‐ corrosion) ductile iron piping would be required.

4.2.7.2 Major Equipment List Table 4‐9 summarizes the major equipment required for cooling sludge.

Table 4‐9. Summary of the Major Equipment PROJECT COMPONENT QTY. NOTES Cooling Water Pump Station AS Effluent Cooling Pumps 2 2,000 gpm (1 Duty, 1 Standby) Cooling Water HEX, plate‐and‐frame 3 1,000 gpm (2 Duty, 1 Standby), Titanium Cooling Water Treatment Pre‐Strainer 2 3400 gpm, 200 micron (1 Duty, 1 Standby) UF Feed Tank 1 ‐ UF Backwash Tank 1 ‐ UF Feed Pumps 2 1700 gpm, 30 psi (1 Duty, 1 Standby) UF Skids 2 1700 gpm (1 Duty, 1 Standby) NF Feed Tank 1 ‐ NF Backwash Tank 1 ‐ High Pressure NF Booster Pumps 4 1000 gpm, 150 psi (3 Duty, 1 Standby) NF skids 4 1000 gpm (3 Duty, 1 Standby) Sludge Cooling HEX, Concentric Tube 6 280 gpm (5 Duty, 1 Standby) NF/UF CIP Tanks and Pump TBD TBD Secondary Effluent Cooling Pumps 2 2,000 gpm (1 Duty, 1 Standby)

4.2.7.3 Facility Layout The UF/NF softening facility houses the two UF skids, four NF skids, feed and transfer pumps, and clean‐in‐place equipment (Figure 4‐13). Clean‐in‐place tanks, including chemical storage and backwash tanks, feed tanks and product tanks are housed outdoors.

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Figure 4‐13. UN/NF Facility Layout

The Plant Water Cooling pump station houses two high‐flow low‐head pumps along with the titanium plate‐and‐frame cooling water heat exchanger (Figure 4‐14). The facility has a preliminary size to accommodate piping, fittings, valves, and instrumentation. The electrical room can be shared with the cooling water softening facility.

Figure 4‐14. Plant Water Cooling Pump Station

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The sludge cooling HEXs require lengthy clear space and at least two utility stations for periodic cleaning and maintenance as shown in Figure 4‐15.

Figure 4‐15. Sludge Cooling Heat Exchangers

4.2.8 Interim Pre‐Processed SSO Receiving An interim pre‐processed SSO receiving facility would allow OCSD to start a pre‐processed SSO co‐ digestion program, and depending on the success of this program, the facility can be expanded following the construction of the thermophilic digesters.

4.2.8.1 Description Results from TM‐5 indicates that existing digesters at Plant No. 2 have capacity to accept 137 to 580 wtpd of pre‐processed SSO by 2028 depending on solids flows and loads. After discussions with OCSD staff, it is recommended that the interim SSO facility be sized to accept up to 250 wtpd (50,000 gallons per day) of pre‐processed SSO. Although the evaluation results showed higher amount of pre‐process SSO that could be accepted, a smaller interim facility would allow OCSD to start the co‐digestion program without spending too much on the capital. It is also recommended that the initial contracts with the waste haulers should be no more than 150 wtpd. The contracted amount of SSO can be increased if the solids flows and loads turn out to be less than expected. A general process flow diagram showing the major components of the interim SSO facility is shown in Figure 4‐16.

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20,000 GAL 20,000 GAL TANK TANK

Figure 4‐16. General Process Flow Diagram for the Interim Pre‐Processed SSO Receiving Facility at Plant No. 2

It is anticipated that pre‐processed SSO would be hauled into the plant site up to 12 hours per day, 5‐6 days per week. Pre‐processed SSO feed to the digesters should be 24 hours per day in order to achieve a relatively continuous digester gas flow to the CenGen facilities. Pre‐processed SSO feed should be blended with the existing sludge feed to the digesters via the existing primary sludge blending facility. The existing primary sludge blending facility buffers the variable flow rate of primary sludge through tank storage and allows a more consistent feed of primary sludge to the digesters. There will be weekend days and holidays without importation of pre‐processed SSO to Plant No. 2. By controlling the pre‐processed SSO feed rate, the operator would transfer all pre‐ processed SSO to the digesters by the “end of the day” and the receiving tanks would be empty and ready for the next day’s deliveries. Therefore, the maximum storage time in the receiving tanks would be limited to 12 hours to minimize odor potential.

The interim SSO receiving facility needs infrastructure support for pre‐processed SSO leakage/overflow/containment, wash down drainage systems, process water for wash down, electrical power, and linkage with the plant control system.

As previously discussed in TM‐5, there are four potential locations for the interim pre‐processed SSO facility. Figure 4‐17 highlights the four possible locations. Sites A, B, and C are similar to the Citrus receiving facility but would only have room for smaller tanks, therefore less capacity. These sites would be ideal for a 100 wtpd facility. However, Site D has adequate space to provide additional space for a 250 wtpd facility. Also, Site A may require coordination with project P2‐98,

Final – May 9, 2017 4‐25 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District replacement of primary clarifiers, where construction of new primary clarifiers could impede truck access to the Site A location.

Figure 4‐17. Locations of Potential Interim Pre‐Processed SSO Receiving Facilities

4.2.8.2 Major Equipment List The interim pre‐processed SSO receiving facility would be designed to process 150 wtpd and sized to receive up to 250 wtpd (50,000 gallons per day) of pre‐processed SSO. This would provide OCSD with the opportunity to assess the market potential as well as gain valuable operation experience. Having an interim facility would also allow OCSD with time to decide if a larger or smaller permanent facility is desired.

Incoming pre‐processed SSO should be pumped directly from the collection vehicles into the pre‐ processed SSO receiving tank. A summary of the required receiving tanks, geometry, and sizing is presented in Table 4‐10.

Table 4‐10. Pre‐Processed SSO Receiving Facility Design Criteria ITEM VALUE Number of storage tanks 2 (both duty) Tank geometry Circular cone bottom Storage tank volume, each 20,000 gallons (50,000 gals) Detention time 17.5 hours

Major equipment associated with the pre‐processed SSO receiving facility are presented in Table 4‐11.

Final – May 9, 2017 4‐26 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Table 4‐11. Major Equipment Comprising the Interim Pre‐Processed SSO Receiving Facility EQUIPMENT TYPE VALUE Number of 12,500 gallon storage FRP or SS 2 tanks Receiving/recirculation pump Progressing Cavity 3 (2 duty, 1 standby)

Digester feed pumps Progressing cavity 2 (1 duty, 1 standby)

Odor control treatment Carbon Canister 2

If the interim facility and equipment are sized for 250 wtpd, the tanks and pumps could be relocated and reused in the ultimate facility, therefore eliminating a future cost. Allowing for the ability to install more capacity in the future would also reduce the payback duration.

4.2.8.3 Facility Layout The facility would consist of two 20,000‐gallon storage tanks, three receiving pumps, and two feed pumps, as shown in Figure 4‐18.

Figure 4‐18. Conceptual Layout of the Interim Pre‐Processed SSO Receiving Facility

Final – May 9, 2017 4‐27 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

4.2.9 Ultimate Pre‐Processed SSO Receiving Following the construction of the thermophilic digesters, a long‐term pre‐processed SSOreceiving facility can be constructed to utilize available digestion capacity.

4.2.9.1 Description It is assumed that the digestion operation will convert from mesophilic digestion to TPAD as the new digesters plan to be in operation by the end of 2028. The amount of pre‐processed SSO that can be co‐digested under TPAD operation would increase significantly. Results from TM‐5 indicate that the available digester capacity can accommodate 320 to 810 wtpd of pre‐processed SSO under TPAD operation, depending on solids flows and loads. Based on this analysis, the BV/BC team recommends a long term pre‐processed SSO receiving capacity of 500 wet tons per day for Plant No. 2. Capacity of the ultimate pre‐processed SSO receiving facility should be re‐evaluated as OCSD staff gain more experience from operating the interim pre‐processed SSO receiving facility and more solids flows and loads data become available. A general process flow diagram showing the major components of the interim pre‐processed SSO facility is shown in Figure 4‐19.

Figure 4‐19. Ultimate Pre‐Processed SSO Receiving Facility Process Schematic

Final – May 9, 2017 4‐28 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

SSO odors can result from volatilization of nitrogen‐ and sulfur‐rich organic compounds that are common in many types of pre‐processed SSOs. Volatilization products include, but are not limited to, ammonia (NH3), mercaptans, and hydrogen sulfide, which produce distinct, powerful odors. Therefore, it is recommended that foul air from the pre‐processed SSO storage tanks be treated by an odor control system. Activated carbon may serve as a passive odor control system as the tanks are filled and drawn down. An evaluation of alternate technologies, such as a dual media odor control vessel, is recommended during the design phase to select the most appropriate technology for the facility.

4.2.9.2 Major Equipment List Major equipment associated with the pre‐processed SSO facility are presented in Table 4‐12.

Table 4‐12. Major Equipment Comprising the Interim Pre‐Processed SSO Receiving Facility EQUIPMENT TYPE VALUE Number of 20,000 gallon storage tanks FRP or SS 4 Receiving/recirculation pump Progressing Cavity 4 (2 duty, 2 standby) Digester feed pumps Progressing cavity 2 (1 duty, 1 standby) Odor control treatment Carbon Canister 2

4.2.9.3 Facility Layout The recommendation is that the facility would be designed to receive up to 110,000 gallons per day (500 wtpd at 12‐15% TS), as shown in Figure 4‐20. This volume equates to 22 trucks per day at 5,000 gallons per truck. The receiving pump capacity is designed to allow a 17‐minute unloading time. The BV/BC team estimates that trucks would deliver pre‐processed SSO at an even rate for 6‐ 8 hours per day, while feeding the digesters 24 hours per day. The total tank storage of 80,000 gallons would provide approximately 17.5 hours of storage.

Final – May 9, 2017 4‐29 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Figure 4‐20. Ultimate Pre‐Processed SSO Receiving Facility

4.2.10 Gas Handling Facilities The digester gas handling facility replacement was evaluated under a previous study, SP‐141. The new digester gas handling facility project will be executed under a future project, J‐124. Digester gas production from SP‐141 was compared to the digester gas projections conducted under TM‐5 to determine the recommended facility capacity to be installed with J‐124.

Two conditions were evaluated in TM 5 to project digester gas production for both Plant No. 1 and Plant No. 2, as follows:

 Digester gas production for Plant No. 1 and Plant No. 2 under TM‐1 Loading Condition 1. For Condition 1, the pre‐processed SSO imported to Plant No. 2 is 500 wtpd based on the maximum capacity for the ultimate pre‐processed SSO receiving facility. The results for Condition 1 are given in Table 4‐13.  Digester gas production for Plant No. 1 and Plant No. 2 under TM‐1 Loading Condition 2. For Condition 2, the pre‐processed SSO imported to Plant No. 2 is 320 wtpd is based on the maximum allowable pre‐processed SSO for Plant No. 2 digesters in Year 2045 from TM‐5, Table 5‐9. The results for Condition 2 are given in Table 4‐14.

Final – May 9, 2017 4‐30 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Table 4‐13. Digester Gas Productions from Plant No. 1 and Plant No. 2 under Condition 11 COMBINED LOADING LOAD TO PLANT NO. 1 PLANT NO. 2 PLANT NO. 1 AND CONDITION DIGESTERS (SCFM)2 (SCFM)3 PLANT NO. 2 (SCFM) Annual Average Sludge 1,840 1,380 3,220 SSO N/A5 850 850 Combined 1,840 2,230 4,070 Peak 15‐Day Sludge 2,210 1,660 3,870 SSO N/A5 850 850 Combined 2,210 2,510 4,720 Peak Hour4 Sludge 2,760 2,070 4,830 SSO N/A5 1,280 1,280 Combined 2,760 3,350 6,110 Notes: 1. Refer to Appendix H.2 and Appendix H.3 for detailed calculations. 2. Plant No. 1 gas production based on 2045 solids flows and loads under Condition 1. 3. Plant No. 2 gas production based on 2045 solids flows and loads under Condition 1 and 500 wtpd pre‐processed SSO. 4. Peak hour gas flow equals 1.5 times annual average gas flow. 5. N/A = not applicable.

Table 4‐14. Digester Gas Productions from Plant No. 1 and Plant No. 2 under Condition 21

COMBINED PLANT LOADING LOAD TO PLANT NO. 1 PLANT NO. 2 NO. 1 AND PLANT CONDITION DIGESTERS (SCFM)2 (SCFM)3 NO. 2 (SCFM)

Annual Sludge 1,470 1,720 3,190 Average SSO N/A5 540 540 Combined 1,470 2,260 3,730 Peak 15‐Day Sludge 1,770 2,070 3,840 SSO N/A5 540 540 Combined 1,770 2,610 4,380 Peak Hour4 Sludge 2,200 2,580 4,800 SSO N/A5 810 810 Combined 2,200 3,390 5,590 Notes: 1. Refer to Appendix H.2 and Appendix H.3 for detailed calculations. 2. Plant No. 1 gas production based on 2045 solids flows and loads under Condition 2. 3. Plant No. 2 gas production based on 2045 solids flows and loads under Condition 2 and 320 wtpd pre‐processed SSO. 4. Peak hour gas flow equals 1.5 times annual average gas flow. 5. N/A = not applicable.

Final – May 9, 2017 4‐31 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

For Plant No. 1 and combined Plant No. 1 and Plant No. 2, the maximum digester gas production is under Condition 1 (Table 4‐13). For Plant No. 2, the maximum digester gas production is under Condition 2 (Table 4‐14).

The CenGen facilities need to handle the peak 15‐day digester gas flow for both plants (4,720 scfm from Table 4‐3). Table 4‐15 below shows the capacity of the CenGen facilities at both plants. There is a combined capacity of 6,565 scfm with all CenGen units in service. With one largest sized CenGen unit out of service, the total CenGen capacity for digester gas is 5,690 scfm, which exceeds the combined 15‐day peak gas flow under Conditions 1 and 2 (4,720 scfm) and the combined peak hour gas flow for Condition 2 (5,590 scfm). With two largest size CenGen units out of service, the total CenGen capacity for digester gas is 4,815 scfm which is slightly larger than the combined maximum gas production of 4,720 scfm. This analysis excludes digester gas utilization for sludge heating. Given the capacity of CenGen, it is anticipated that OCSD would have sufficient capacity to accommodate gas production from pre‐processed SSO and projected solids loading with minimal flaring. OCSD should assess the impacts of pre‐processed SSO addition on digester gas production over time with the interim pre‐processed SSO receiving facility to determine how much pre‐ processed SSO may be imported without exceeding the CenGen capacity.

Table 4‐15. CenGen Digester Gas Utilization Capacity GAS UTILIZATION EQUIPMENT GAS FLOW PER UNIT TOTAL GAS FLOW

Plant 1 CenGen – 3 units 730 scfm 2,190 scfm

Plant No. 2 CenGen – 5 units 875 scfm 4,375 scfm

Combined CenGen capacity with 2 N/A 4,815 scfm largest units out of service

The projected peak 15‐day digester gas flows for Plant No. 2 are shown in Figure 4‐21 under Condition 2 over a range of pre‐processed SSO imports (100 – 300 wtpd). The maximum gas flow rate for Plant No. 2 is 2,610 scfm under these conditions.

Final – May 9, 2017 4‐32 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Figure 4‐21. Projected Peak 15‐day Digester Gas Flows for Plant No. 2

The recommended future gas handling capacities from Study SP‐141 are given in Table 4‐16. In each case, the planned capacity would handle the peak hour flow rate for both Plant No. 1 and Plant No. 2 when compared with Tables 4‐13 and 4‐14. Project J‐124 should install the gas handling capacity provided from SP‐141 and presented in Table 4‐16 as this capacity is expected to meet future gas projections from both sludge and co‐digestion. The recent siloxane removal facilities installed under Project J‐111 have a firm design capacity of 3,500 scfm and are also adequate for peak hour flows at either Plant No. 1 or Plant No. 2 in Tables 4‐13 and 4‐14. However, it is noted that the moisture content of the digester gas should increase significantly when TPAD is implemented for sludge stabilization and should be evaluated under Project J‐124.

Table 4‐16. Project J‐124 Digester Gas Design Capacities PLANT NO. 1 PLANT NO. 2 EQUIPMENT FIRM DESIGN CAPACITY FIRM DESIGN CAPACITY (SCFM) (SCFM) Gas Compressors 1 3,500 scfm 3,500 scfm

Waste Gas Flares 1 3,600 scfm 3,600 scfm

Gas Dryer 1 3,500 scfm 3,500 scfm

Note: 1. Gas flow capacity is adequate; however, the moisture content in the digester gas should increase due to future TPAD facilities.

Final – May 9, 2017 4‐33 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

4.2.10.1 Major Equipment List OCSD Project SP‐141 was a study that led to recommended improvements for digester gas handling facilities at both Plant No. 1 and Plant No. 2, to be implemented in Project J‐124. The recommended major equipment associated with Project J‐124 is summarized in the table below and the sizing of equipment has been retained from the recommendations in SP‐141. The digester gas compressors are sized with a firm capacity to handle peak hour digester gas flow rates with one compressor out of service. The gas dryer system is sized to handle the peak hour digester gas flow rate with internal redundancy within the treatment system components. The digester gas flares are sized to handle the peak hour gas flow rate with no units out of service.

Table 4‐17. Digester Gas Utilization Major Equipment List EQUIPMENT TYPE VALUE Low pressure digester gas vents PRV/VRVs with flame arrestors Each digester Digester gas compressors (1,750 scfm) Rotary screw 3 (2 duty, 1 standby) Chilled water system (heat One system, internal Gas dryer system (3,500 scfm) exchanger and chiller) redundancy within system Digester gas flares (1,200 scfm each) High efficiency, low air emissions 3 duty

4.2.10.2 Facility Layout Figure 4‐22 depicts the layout of the gas handling facility as described in SP‐141.

Final – May 9, 2017 4‐34 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Figure 4‐22. Gas Handling Facility Layout from SP‐141

4.2.11 Ferric Chloride Facility The existing ferric chloride facility would need to be relocated. Relocation would include all of the existing pumps, tanks, and equipment.

4.2.11.1 Description The suggestion is to relocated the existing ferric chloride feed facility to free up site space allocated for other treatment processes.

4.2.11.2 Major Equipment List There is no new major equipment for the ferric chloride facility.

4.2.11.3 Facility Layout The layout of the facility should remain similar to its current layout, which is shown in Figure 4‐23. The facility needs to be relocated to accommodate space requirements for construction.

Final – May 9, 2017 4‐35 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Figure 4‐23. A Diagram of the Ferric Chloride Facility Layout

4.2.12 Centrifuge Dewatering Facility The Centrifuge Dewatering Facility is currently in construction under project P2‐92. The facility was designed to dewater an annual average of 180,000 dry lb/day of digested sludge based on projected 2020 loads. Part of the design of P2‐92 included space planning for the ultimate buildout capacity. The ultimate buildout capacity assumed a 60% increase in design loading and requires expansion of the centrifuge dewatering building to the north to house two additional dewatering centrifuges, see Figure 4‐24. However, the buildout capacity is projected beyond 2045, the planning period of this master plan, and expansion of the Centrifuge Dewatering Facility is not recommended under this masterplan.

Final – May 9, 2017 4‐36 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Figure 4‐24. P2‐92 Future Footprint Concept from P2‐92 Preliminary Design Report

4.3 SITE LAYOUT The conceptual design included development of a site layout to reflect the facility improvements. All site layout drawings are given in Appendix C (enclosed Flash Drive) and published as a hard copy at the end of TM‐6. The layout includes references to corresponding CIP project elements, which are described in the following sections of this TM and shown in Figure 4‐25. For planning purposes the site layout shows the gas holder being rebuilt in place, however if the space is required for another process and/or for ease of construction sequencing, the gas holder would likely be relocated. Additionally, the interim pre‐processed SSO receiving facility is shown at Digester S. This is the recommended location based on containments due to location and facility size as well as optimal truck path.

Final – May 9, 2017 4‐37 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Figure 4‐25. Site Layout

Final – May 9, 2017 4‐38 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

5.0 CIP Development for New Digestion and Pre‐Processed SSO Co‐Digestion Facilities Under Task 6, the BV/BC Team developed a recommendation of projects, project schedules, and associated construction costs for the Plant No. 2 solids Capital Improvement Plan (CIP) projects. This section describes these elements for each of and this section describes the CIP projects required to implement the conceptual design for the new digestion and pre‐processed SSO co‐ digestion facilities.

The CIP projects for the new digestion and pre‐processed SSO co‐digestion facilities can be summarized as follows:  P2‐501 Perimeter Screening  P2‐502 Interim Pre‐Processed SSO Receiving Facility  P2‐503 Relocate and Demo Warehouse and Collections Parking Area  P2‐504 TPAD Project  P2‐504A Class A Batch Tanks  P2‐504B Thickened Sludge Feed Facility  P2‐504C Ferric Chloride Facility  P2‐505 Replace Digesters P, Q, R, S  P2‐506 Ultimate Pre‐Processed SSO Receiving Facility  P2‐507 Replace Digesters I, J, K  P2‐508 Digester Demolition

Each of these projects is described further throughout the remainder of this section. 5.1 P2‐501 – PERIMETER SCREENING Project P2‐502 represents the development of a visual buffer to provide perimeter screening of the new facilities from Brookhurst Street and Talbert Marsh.

5.1.1 Background Currently, there are two concrete masonry unit (CMU)‐block retained vegetated berms approximately 15 ft high located along Talbert Marsh. This project would improve or replace the existing berm and extend the perimeter screening to provide a visual buffer for all the new facilities and the associated construction activities.

5.1.2 Project Elements  Improve or replace the existing berm along Talbert Marsh.  Extend the perimeter screening to provide a visual buffer for all the new facilities and the associated construction activities along Brookhurst St.

Final – May 9, 2017 5‐1 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

5.1.3 Sequencing  The perimeter screening project should be completed prior to start of construction associated with relocation of the warehouse (P2‐503) and the new thermophilic digesters (P2‐504) as the new perimeter can then be used to screen both construction activities and the final facilities.

5.1.4 Construction Cost Estimate A budgetary cost estimate was developed for the Plan No. 2 solids CIP. Table 5‐1 presents the cost estimates for each project.

Table 5‐1. Summary of Probable Construction Cost for P2‐501

DESCRIPTION CONSTRUCTION COST1

General Conditions $ 104,000 Sitework and Demolition $ 27,000 Concrete $ 94,000 Stone and Masonry $ 601,000 Thermal Protection $ 20,000 Fire Suppression $ 3,000 Plumbing $ 20,000 Earthwork $ 230,000 Exterior Improvements $ 158,000 Utilities $ 3,000 Total $ 1, 300,000 Notes: 1. Cost estimate basis: mid‐point of cost range (‐30%/+50%) using December 2016 dollars. 2. Refer to Appendix E for detailed cost estimate.

5.2 P2‐502 – INTERIM PRE‐PROCESSED SSO RECEIVING FACILITY The capacity and potential locations for an interim pre‐processed SSO receiving facility were evaluated in TM5. An interim pre‐processed SSO receiving facility allows OCSD to assess the pre‐ processed SSO market and process impacts through a pre‐processed SSO demonstration project.

5.2.1 Description An interim pre‐processed SSO facility with a capacity up to 250 wtpd can be built as an initial co‐ digestion program; however, OCSD plans to contract to accept 150 wtpd, initially. Based on data analysis, food waste co‐digestion at Plant No. 2 is feasible in 2018, when diversion of Plant No. 1 primary sludge to Plant No. 2 is estimated to be reduced or stopped upon completion of P1‐100, P1‐ 101, and IRWD solids handling facility.

Final – May 9, 2017 5‐2 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

5.2.2 Project Elements  Evaluate locations for construction of interim pre‐processed SSO receiving facility, including considerations for truck traffic, pre‐processed SSO offloading, and piping connections to the digestion process.  Evaluate the details of pre‐processed SSO additions at the digesters. The addition of pre‐ processed SSO may occur to all digesters, one digester, or several digesters.  The addition of pre‐processed SSO would result in significant increases in gas production. Evaluate the anticipated gas production rates associated with pre‐processed SSO co‐ digestion and determine if sufficient capacity exists in the gas piping, waste gas burners, and digester gas emergency relief devices.  Site location and truck access may be impacted by construction related to P2‐98, construction of primary clarifiers. Access to site should be coordinated with P2‐98 construction planning.

5.2.3 Sequencing  Construct interim pre‐processed SSO receiving facility and implement demonstration pre‐ processed SSO program in 2018 or after. Investigate alternative delivery methods of partnerships with waste management companies to expedite construction and implementation schedule.  Depending on site footprint and digester gas capacity limitations, consider providing the ability to install an initial receiving facility with the ability to expand the capacity in the future. Alternatively, consider installing multiple receiving facilities to distribute pre‐ processed SSO to digesters and increase overall receiving capacity.

5.2.4 Construction Cost Estimate A budgetary cost estimate was developed for the Plan No. 2 solids CIP. Table 5‐2 presents the cost estimates for each project.

Table 5‐2. Summary of Probable Construction Cost for P2‐502

DESCRIPTION CONSTRUCTION COST 1

Sitework and Earthwork $ 550,000 Concrete $ 410,000 Metals $ 20,000 Process Equipment $ 1,030,000 Process Piping $ 500,000 Electrical $ 380,000 Instrumentation and Communications $ 190,000 Total $ 2,600,000 Notes: 1. Cost estimate basis: mid‐point of cost range (‐30%/+50%) using December 2016 dollars. 2. Refer to Appendix E for detailed cost estimate.

Final – May 9, 2017 5‐3 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

5.3 P2‐503 – RELOCATE AND DEMO WAREHOUSE AND COLLECTIONS PARKING AREA The existing above grade warehouse would need to be demolished and then reconstructed at a new location. The current warehouse and collections parking area may be used as staging area for P2‐ 504 (TPAD Project) and would ultimately serve as the location for the Class A batch tanks for P2‐ 504A. The warehouse and collections parking area would need to be relocated, and potentially, the collections group can be located off site at Plant No. 1 next to the auto shop.

5.3.1 Description The warehouse demolition is proposed to free up the site for construction staging and laydown area for the TPAD project (P2‐504). Upon completion of the main TPAD project, the suggestion location for construction of the Class A Batch Tanks is on top of the existing warehouse location under project P2‐504A.

5.3.2 Project Elements  The existing warehouse is approximately 21,000 square feet and should be replaced with a similarly sized building. Potential locations at Plant No. 2 are shown in Figure 5‐1 below.  The existing 38,000 sq. feet collections yard (parking lot) should be relocated, potentially to Plant No. 1. Potential locations are Plant No. 1 are shown in Figure 5‐2 below.  There are three existing catch basins between the existing collections yard and warehouse. The catch basins drain to the plant’s headworks. Construction best management practices should be used to protect the drain from sediment and construction debris.  Currently, the Collections Yard has five large parking spots (40 ft long x 12 ft wide) and nine medium parking spots (25 ft long x 12 ft wide) to accommodate an assortment of trucks utilized by the Collections Group. The relocated collections yard should provide adequate space and truck paths to and from the site, similar to the existing footprint.

Figure 5‐1. Drawing of the Existing and New Locations for the Warehouse

Final – May 9, 2017 5‐4 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Figure 5‐2. An Aerial of the Collections Yard's Existing and Relocation Sites

5.3.3 Sequencing  Based on project sequencing, relocation of the warehouse and collections yard should be early in the CIP implementation schedule as it is anticipated that the area currently occupied by these areas would be required for use by the contactor during construction of P2‐504. Relocation of these areas should therefore be complete prior to the start of construction of P2‐504.

5.3.4 Construction Cost Estimate A budgetary cost estimate was developed for the Plan No. 2 solids CIP. Table 5‐3 presents the cost estimates for each project.

Table 5‐3. Summary of Probable Construction Cost for P2‐503

DESCRIPTION CONSTRUCTION COST1

Sitework and Demolition $ 232,000 Concrete $ 837,000 Thermal Protection $ 149,000 Furnishings $ 113,000 Special Construction $ 1,324,000 Fire Suppression $ 329,000 Plumbing $ 426,000

Final – May 9, 2017 5‐5 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

DESCRIPTION CONSTRUCTION COST1

HVAC $ 387,000 Electrical $ 882,000 Earthwork $ 68,000 Exterior Improvements $ 366,000 Total $ 5,200,000 Notes: 1. Cost estimate basis: mid‐point of cost range (‐30%/+50%) using December 2016 dollars. 2. Refer to Appendix E for detailed cost estimate.

5.4 P2‐504 – TPAD PROJECT ELEMENTS TPAD refers to the on‐site digestion process that was selected for implementation at OCSD’s Plant No. 2. The TPAD project proposed for the biosolids CIP has been developed under this task to transition Plant No.2 from a CMAD facility to a TPAD facility in the quickest and most logical way in order to mitigate seismic and operational risks. This project refers to the construction of six 110‐ft diameter digesters designed to operate in either mesophilic or thermophilic operation.

5.4.1 Project Elements  Construct six new 110‐ft diameter digesters capable of mesophilic or thermophilic operation in the south west corner of the plant.  Modifications to several existing facilities to accommodate the new TPAD process as described above. These include: sludge cooling, hydronic loop modifications, additional hot water boilers, digester feeding, digested sludge transfer, digester gas system, digester overflow, and ferric feed piping.  A sludge cooling facility is suggested to cool the thermophilic digested sludge prior to transfer to the mesophilic stage. Sludge cooling provides adequate temperature in the mesophilic phase to improve biosolids quality, and without cooling, the biosolids product may exhibit slightly greater odors. This PDR evaluated effluent cooling for this purpose. The basis of this design assumes a conservative approach to process cooling using treated plant effluent, including filtration and water softening. The current CenGen cooling system operation also uses plant water, and only filtration is required. Given the current experience with the CenGen cooling process, it is believed that a similar approach can be considered for this project, but due to the complex nature of cooling processes, further evaluation into cooling alternatives is recommended.  The existing hot water loop should be extended to the new thermophilic digestion facility and include modifications to allow for elevated hot water temperatures. Increasing the hot water loop temperature would limit the ability of CenGen to waste the cooling water jacket heat into the hydronic loop. Modifications to the CenGen heat recovery and wasting system is suggested. In addition, the existing hot water loop pipe design would need to be evaluated to determine if the current thermal expansion control system can accommodate the higher operating temperatures.

Final – May 9, 2017 5‐6 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

 Additional hot water boilers are suggested to support the new thermophilic digesters. These boilers should be installed as part of the TPAD project and should be designed to operate on both digester gas and natural gas. Evaluations into cost effectiveness of the different fuels indicate that the primary fuel in the hot water boilers should be designed for digester gas.  The startup and initial operation of the TPAD digesters may require modifications to the current digester feed system, until the new DFF is constructed. These modifications may include new, higher capacity pumps at both the SBF and DAFTs and new feed piping. Digester feed modifications are described in more detail below with the P2‐504B.  Transfer piping from the new thermophilic digesters to the existing mesophilic digesters are suggested to operate in TPAD configuration. Transfer piping and control valves should be installed and tested while the existing digesters remain in operation.  Connection to the existing digester gas manifold from the new thermophilic digesters is recommended. The existing mesophilic digesters must remain in operation. A digester gas system outage or other strategies should be considered to facilitate connection of new gas piping to the existing gas system.  Emergency overflow piping from the new thermophilic digesters should be coordinated with yard piping and allow gravity flow to an appropriate designation. Provisions for rapid volume expansion should be also be considered in the overflow system design. For cost estimating purposes, it was assumed gravity flow was not possible and that a new pump station would be installed to convey overflowing sludge to the headworks or similar location.  Modifications to the existing ferric feed system are needed to allow ferric dosing of digester sludge to the new DFF and thermophilic digesters. More details of these requirements will be described in the sequencing description for P2‐504C. Following relocation of the ferric feed system, the feed dosing should be modified to accommodate the new location.  A new power building is recommended for installation under this project. The building would have a room for 12kV switchgear, 480V switchgear, and MCCs for the six digesters. Space should be allocated outside for four transformers. The power building would feed the six thermophilic digesters and should plan for future feed to the rebuilt P, Q, R, and S (105’ mesophilic digesters) and I, J, and K (80’ mesophilic digesters), the thickened sludge blend tank, pre‐processed SSO receiving facility, batch tanks, and other miscellaneous ancillary facilities. Based on the project design, the approximate peak load from the digestion facilities would be 2,300 HP, with power being drawn from CenGen.  A ramp for truck access to the thermophilic digestion equipment basement is required for maintenance purposes.

5.4.2 Sequencing  The TPAD process was recommended to mitigate the current seismic risk at Plant No. 2, allow for opportunities to produce Class A biosolids, and provide further reliability and redundancy, and as such the P2‐504 should be started as soon as possible.

Final – May 9, 2017 5‐7 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

5.4.3 Construction Cost Estimate A budgetary cost estimate was developed for the Plan No. 2 solids CIP. Table 5‐4 presents the cost estimates for each project.

Table 5‐4. Summary of Probable Construction Cost for P2‐504

DESCRIPTION CONSTRUCTION COST1

General Conditions $ 2,622,000 Sitework and Demolition $ 316,000 Concrete $ 25,852,000 Stone and Masonry $ 197,000 Metals $ 443,000 Thermal Protection $ 21,000 Finishes $ 944,000 Special Construction $ 2,193,000 Plumbing $ 800,000 HVAC $ 7,508,000 Electrical $ 27,496,000 Instrumentation and Communications $ 15,610,000 Earthwork $ 30,728,000 Exterior Improvements $ 1,155,000 Utilities $ 1,169,000 Process Pipe Fittings and Valves $ 15,072,000 Process Equipment $ 21,955,000 Total $ 154,100,000 Notes: 1. Cost estimate basis: mid‐point of cost range (‐30%/+50%) using December 2016 dollars. 2. Refer to Appendix E for detailed cost estimate.

5.5 P2‐504A – CLASS A BATCH TANKS The addition of batch tanks to the TPAD process would allow OCSD to produce Class A biosolids. It is suggested that the batch tank project (P2‐504A) be separated from the TPAD project (P2‐504) from a planning standpoint and can be added to the P2‐504 TPAD project, if desired before the RFP is released.

5.5.1 Description Class A batch tank is recommended to produce Class A biosolids per EPA 503 regulations through batch holding over a specified time and temperature. Class A batch tanks are implemented after the thermophilic digestion phase of TPAD and are operated at thermophilic temperatures.

Final – May 9, 2017 5‐8 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

5.5.2 Project Elements  Construct six Class A batch tanks to allow operation of TPAD as a Class A process.  The open footprint on the site is limited, and the space for the batch tanks could be used by the contractor for staging during construction of P2‐504.  Two piping and utility tunnels would need to be constructed to connect the digesters to the batch tanks as well as to the secondary effluent sludge cooling system.  If the construction of the batch tanks is sequenced such that the batch tanks are constructed after P2‐504, provisions in the batch tank startup schedule should be adjusted to facilitate the transition of operation from Class B to Class A. For example, the Class B digested sludge in the mesophilic digesters would need to be dewatered and refilled with Class A sludge before the process is considered Class A. It is not expected that mixture of Class A and B sludge would be considered as Class A biosolids without additional pathogen testing. Additional schedule would be required to accommodate draining and filling of mesophilic digesters in a strategic manner to avoid process upsets during the transition from Class B to A. Alternatively, to draining the mesophilic tanks, pathogen testing could be used to verify Class A requirements are being achieved with the process. With this approach, the mesophilic digesters would remain in operation and would receive Class A digested sludge form the batch tanks. Over several HRTs, the contents of the mesophilic digesters would wash out and eventually meet Class A levels.  Reactivation and regrowth of indicator organisms after dewatering has been a concern in the industry. Monitoring of indicator organism and pathogen concentrations would help OCSD assess this potential concern. Partnering with other agencies adopting TPAD and TPAD Class A would also help to better assess this risk. It is anticipated that pathogen enumeration (such as Salmonella) would be a reliable testing method to confirm Class A. Providing additional features in the digestion process, like the ability to place tanks into series, has been shown to reduce the potential for reactivation and regrowth, and this flexibility should be considered for Plant No. 2.

5.5.3 Sequencing  After completion of the batch tanks, the startup schedule for conversion to Class A should include draining of the mesophilic digesters and cleaning to prevent cross‐contamination of Class B and Class A material. Further evaluation startup and Class A conversion is recommended.  The addition of batch tanks is not necessary to implement TPAD operation, and this evaluation assumed that the batch tanks would be built after the new thermophilic digesters (P2‐504), allowing the contractor to use the footprint of the batch tanks during construction of P2‐504 for staging.

5.5.4 Construction Cost Estimate A budgetary cost estimate was developed for the Plan No. 2 solids CIP. Table 5‐5 presents the cost estimates for each project.

Final – May 9, 2017 5‐9 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Table 5‐5. Summary of Probable Construction Cost for P2‐504A

DESCRIPTION CONSTRUCTION COST1

General Conditions $ 110,000 Sitework and Demolition $ 47,000 Concrete $ 9,135,000 Finishes $ 92,000 Plumbing $ 139,000 Electrical $ 4,248,000 Instrumentation and Communications $ 850,000 Earthwork $ 5,582,000 Exterior Improvements $ 185,000 Utilities $ 185,000 Process Pipe Fittings and Valves $ 2,584,000 Process Equipment $ 3,049,000 Total $ 26,300,000 Notes: 1. Cost estimate basis: mid‐point of cost range (‐30%/+50%) using December 2016 dollars. 2. Refer to Appendix E for detailed cost estimate.

5.6 P2‐504B – DIGESTER FEED FACILITY (DFF) The new DFF would replace the existing SBF where primary sludge and scum is blended and fed to the digesters. The new DFF would allow blending of primary sludge and thickened waste activated sludge for continuous feed to the digester. This facility would also include the addition of an odor control system.

5.6.1 Description The DFF would facilitate blending and equalization of PS, TWAS, scum, and potentially pre‐ processed SSO and a relatively constant feed anaerobic digesters. The feed system would accommodate both CMAD and TPAD modes of operation.

5.6.2 Project Elements  Construct the DFF, including the two DFF blend tanks, tank mixing system, digester feed pumps, and associated odor control facility.  If constructed in parallel with P2‐504, the startup, testing, and commissioning of the facility should be executed with the new thermophilic digesters.  A transition from the existing feeding system from the SBF and DAFTs (to the existing mesophilic digesters) to the new thermophilic digesters could be completed at startup of the DFF and TPAD. This approach would simplify any modifications to the existing digester feed system.

Final – May 9, 2017 5‐10 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

 If the DFF is sequenced to be constructed after P2‐504, temporary modifications to the existing digester feed system is suggested. At a minimum, it is anticipated that new, higher capacity pumps would be required at the SBF and DAFTs and temporary piping and control valves be installed at the new thermophilic digesters to allow feeding the new digesters prior to startup of the DFF.

5.6.3 Sequencing  Construction of the DFF could start after the demolition of the existing cake handling facility.  The DFF could be constructed in parallel with P2‐504 or sequenced later for cash flow purposes.

5.6.4 Construction Cost Estimate A budgetary cost estimate was developed for the Plan No. 2 solids CIP. Table 5‐6 presents the cost estimates for each project.

Table 5‐6. Summary of Probable Construction Cost for P2‐504B

DESCRIPTION CONSTRUCTION COST1

Concrete $ 776,000 Electrical $ 2,983,000 Earthwork $ 408,000 Exterior Improvements $ 81,000 Utilities $ 81,000 Process Pipe Fittings and Valves $ 6,358,000 Process Equipment $ 1,856,000 Total $ 12,600,000 Notes: 1. Cost estimate basis: mid‐point of cost range (‐30%/+50%) using December 2016 dollars. 2. Refer to Appendix E for detailed cost estimate.

5.7 P2‐504C – FERRIC CHLORIDE FACILITY P2‐504C would relocate the existing ferric facility, which currently feeds three digester segments. The recommended relocation site for the facility is adjacent to the new blending facility. The relocation would include all of the match pumps, tanks, and existing equipment.

5.7.1 Background The relocation of the existing ferric chloride feed facility would free up site space allocated for other treatment processes.

5.7.2 Project Elements  Relocate the existing ferric chloride feed facility.

Final – May 9, 2017 5‐11 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

5.7.3 Sequencing  Relocate the existing ferric chloride feed facility when the current footprint is needed for another process facility.

5.7.4 Construction Cost Estimate A budgetary cost estimate was developed for the Plan No. 2 solids CIP. Table 5‐7 presents the cost estimates for each project.

Table 5‐7. Summary of Probable Construction Cost for P2‐504C

DESCRIPTION CONSTRUCTION COST1

Sitework and Demolition $ 87,000 Concrete $ 194,000 Electrical $ 515,000 Earthwork $ 265,000 Process Pipe Fittings and Valves $ 50,000 Process Equipment $ 259,000 Total $ 1,400,000 Notes: 1. Cost estimate basis: mid‐point of cost range (‐30%/+50%) using December 2016 dollars. 2. Refer to Appendix E for detailed cost estimate.

5.8 P2‐505 – REPLACE DIGESTERS P, Q, R, S This project would consist of the demolition of four digesters (P, Q, R, and S) and Power Building C. The current plan for Digesters P, Q, R, and S is to be rebuilt in place, two at a time, because each pair share a common equipment room.

5.8.1 Background Digesters P, Q, R and S require expensive structural modifications and ground improvements to mitigate seismic risks. These digesters are at the end of their useful life, and replacement of these facilities is preferred. P2‐505 would demolish and replace Digesters P, Q, R, and S.

5.8.2 Project Elements  Demolish and replace Digesters P, Q, R, and S.  Demolish Power Building C. A new power building is currently planned to be constructed with P2‐504.  Construction of P2‐505 should be implemented with two digesters at a time to ensure sufficient mesophilic digestion capacity remains online. A minimum of 6.11 Mgal of mesophilic digester volume is anticipated to meet peak 15‐day loads process requirements at the end of the anticipated construction period.

Final – May 9, 2017 5‐12 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

5.8.3 Sequencing  Prior to completion of P2‐504, Digesters P, Q, R, and S should remain in service as their capacity would be required to supplement the other mesophilic digesters in providing reliable solids processing.  Start construction of P2‐505 following completion of P2‐504. Construction should assume two digesters at a time as each pair of digesters share a common mechanical building. Prior to the completion of P2‐504, the digesters should remain in service to provide necessary solids processing capacity.

5.8.4 Construction Cost Estimate A budgetary cost estimate was developed for the Plan No. 2 solids CIP. Table 5‐8 presents the cost estimates for each project.

Table 5‐8. Summary of Probable Construction Cost for P2‐505

DESCRIPTION CONSTRUCTION COST1

General Conditions $ 892,000 Sitework and Demolition $ 7,047,000 Concrete $ 16,362,000 Plumbing $ 184,000 Electrical $ 11,244,000 Earthwork $ 12,559,000 Exterior Improvements $ 982,000 Utilities $ 746,000 Process Pipe Fittings and Valves $ 3,384,000 Process Equipment $ 3,333,000 Total $ 56,800,000 Notes: 1. Cost estimate basis: mid‐point of cost range (‐30%/+50%) using December 2016 dollars. 2. Refer to Appendix E for detailed cost estimate.

5.9 P2‐506 – ULTIMATE PRE‐PROCESSED SSO RECEIVING FACILITY The ultimate pre‐processed SSO receiving facility would replace the interim receiving facility and be constructed to receive a greater capacity of pre‐processed SSO. The capacity and potential locations for the ultimate pre‐processed SSO receiving facility were evaluated in detail in TM 5. The recommended location is next to the new blending facility, where Digesters L & M are currently located.

5.9.1 Background Following successful operation of the interim pre‐processed SSO receiving facility (P2‐502), P2‐506 would allow for expansion of the pre‐processed SSO receiving program through construction of a larger capacity pre‐processed SSO receiving station to replace the interim facility.

Final – May 9, 2017 5‐13 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

5.9.2 Project Elements  Construction of the ultimate pre‐processed SSO receiving facility to expand receiving capacity of pre‐processed SSO.  Construct an odor control facility to treat foul air generated from the ultimate pre‐ processed SSO receiving facility.  Integrate pre‐processed SSO receiving facility into the digester feed system to allow pre‐ processed SSO to be effectively transferred to the digestion process.  The addition of pre‐processed SSO to the digestion process would result in significant increases in gas production. Evaluate the anticipated gas production rates associated with pre‐processed SSO co‐digestion and determine if sufficient capacity exists in the digester gas piping, gas conditioning, and digester emergency relief devices.

5.9.3 Sequencing  Construct the ultimate pre‐processed SSO receiving facility following completion of P2‐504, when significant additional digester capacity becomes available for pre‐processed SSO digestion.

5.9.4 Construction Cost Estimate A budgetary cost estimate was developed for the Plan No. 2 solids CIP. Table 5‐9 presents the cost estimates for each project.

Table 5‐9. Summary of Probable Construction Cost for P2‐506

DESCRIPTION CONSTRUCTION COST1

Sitework and Earthwork $ 680,000 Concrete $ 800,000 Metals $ 180,000 Process Equipment $ 2,210,000 Process Piping $ 730,000 Electrical $ 860,000 Instrumentation and Communications $ 430,000 Total $ 5,900,000 Notes: 1. Cost estimate basis: mid‐point of cost range (‐30%/+50%) using December 2016 dollars. 2. Refer to Appendix E for detailed cost estimate.

5.10 P2‐507 – RELOCATE DIGESTER‐HOLDERS (FORMERLY I, J, K) Project planning for P2‐507 consists of the demolition of seven digesters, Digesters I, J, K, M, N, O, and T. Based on project recommendations, digesters that serve a similar holder function as I and J would be relocated to where existing Digesters M, O, and T are located. These digesters can serve as both holder and active digesters depending on the needs of the plant.

Final – May 9, 2017 5‐14 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

5.10.1 Background Following completion of P2‐504 and P2‐506, P2‐505 would relocate digesters I, J, and K. These digesters require expense structural modifications and ground improvements to mitigate seismic risks. After the completion of P2‐504 and P2‐505, Digesters I, J, and K would be at the end of their useful life, and replacement of these facilities is preferred. P2‐507 would demolish and replace Digesters I, J, and K. These new digesters would serve as mesophilic digesters and holders capable of operation as mesophilic digesters.

5.10.2 Project Elements  Demolish and rebuild Digesters I, J, and K as digesters capable of mesophilic operation or the ability to operate as a holder.  Digester M shares an equipment room with Digester L. Digester L is to be demolished under P2‐506 Pre‐processed SSO Receiving Facility project—that project will retain Digester M and the shared equipment room to be demolished under this project.  Digesters N and O would have to be demolished at the same time as they share an equipment room. Digester T has a stand‐alone equipment room.  Relocation of Digesters I, J, and K would ultimately free up footprint on the site for other process facilities.

5.10.3 Sequencing  Start construction following completion of P2‐505 to ensure sufficient mesophilic digestion capacity remains online during P2‐505.

5.10.4 Construction Cost Estimate A budgetary cost estimate was developed for the Plan No. 2 solids CIP. Table 5‐10 presents the cost estimates for each project.

Final – May 9, 2017 5‐15 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Table 5‐10. Summary of Probable Construction Cost for P2‐507

DESCRIPTION CONSTRUCTION COST1

General Conditions $ 481,000 Sitework and Demolition $ 7,567,000 Concrete $ 9,065,000 Plumbing $ 135,000 Electrical $ 7,434,000 Earthwork $ 8,538,000 Exterior Improvements $ 736,000 Utilities $ 559,000 Process Pipe Fittings and Valves $ 2,407,000 Process Equipment $ 2,371,000 Total $ 39,300,000 Notes: 1. Cost estimate basis: mid‐point of cost range (‐30%/+50%) using December 2016 dollars. 2. Refer to Appendix E for detailed cost estimate.

5.11 P2‐508 – DIGESTER DEMOLITION Under P2‐508, the six remaining digesters should be demolished to free up site footprint for future treatment processes.

5.11.1 Background P2‐508 demolishes the six remaining digesters, Digesters C, D, E, F, G, and H, to free up site footprint for future treatment process facilities. In addition to the digesters, the gas holder next to the digesters would be either rebuilt or relocated.

5.11.2 Project Elements  Demolish Digesters C, D, E, F, and G.  Rebuild or relocate the digester gas holder.

5.11.3 Sequencing  Start construction following completion of the other CIP projects. P2‐508 could begin sooner if the associated mesophilic digester capacity is not required.  The digester gas holder provides a benefit to process operation. Rebuild or relocate the digester gas holder when it reaches the end of its useful life or when the site space is required for another process.

5.11.4 Construction Cost Estimate A budgetary cost estimate was developed for the Plan No. 2 solids CIP. Table 5‐11 presents the cost estimates for each project.

Final – May 9, 2017 5‐16 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Table 5‐11. Summary of Probable Construction Cost for P2‐508

DESCRIPTION CONSTRUCTION COST1

Sitework and Demolition $ 6,481,000 Special Construction $ 97,000 Earthwork $ 764,000 Total $ 7,400,000 Notes: 1. Cost estimate basis: mid‐point of cost range (‐30%/+50%) using December 2016 dollars. 2. Refer to Appendix E for detailed cost estimate.

Final – May 9, 2017 5‐17 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

6.0 Modifications to Existing CIP Projects Under Task 6, the BV/BC Team developed a recommendation of projects, project schedules, and associated construction costs for the Plant No. 2 solids handling CIP, and this section describes potential modifications to existing CIP projects due to changes that resulted from decisions developed during this master plan.

The existing CIP projects potentially impacted by the development of the new digestion and pre‐ processed SSO co‐digestion facilities are summarized as follows:  X‐032 Solids Storage and Truck Loading  J‐124 Digester Gas Handling Facilities  P2‐500 Digester Repairs (formerly P2‐91‐1) 6.1 X‐032 – DEWATERED SLUDGE STORAGE AND TRUCK LOADING REHABILITATION Project X‐032 is the project developed by OCSD Planning Staff to improve the condition of the sludge dewatering truck loadout. The sludge cake silos and truck loading facility was last evaluated for capacity under P2‐92, the centrifuge dewatering project which is currently under construction. Further evaluation under this TM has determined that between digested sludge storage and dewatered cake storage there is adequate capacity to meet projected sludge loadings through the planning period of this masterplan. The truck loading analysis was re‐evaluated with updated 2035 digested sludge loading assuming no solids from IRWD and flow is split evenly between Plant No. 1 and Plant No. 2. The results of the analysis showed a greater variation in weekly operation can accommodate holiday operations, with peak dewatering operation in the middle of the week and storage of digested sludge in sludge storage tanks during the long weekend. This analysis can be found in Appendix I (enclosed Flash Drive) and published as a hard copy at the end of TM‐6. Based on this analysis, no expansion of the sludge cake storage is required; however, a condition assessment performed by OCSD has determined the need for future rehabilitation.

A budgetary cost estimate was developed by OCSD Planning Staff based on condition assessment. The total estimated construction cost for X‐032 is $2.5 million. Note the cost estimate was completed in February 2016. 6.2 J‐124 – DIGESTER GAS HANDLING FACILITIES J‐124 would replace the existing digester gas compressor facility with a new compressor facility and waste gas burners. This project was evaluated in a previous project, SP‐141 Gas Facility Study for Plants No. 1 and 2. The digester gas production rates should increase with the implementation of TPAD and pre‐processed SSO co‐digestion (see Section 3.4.2 and Section 4.2.10). Based on current assessments, the scope of J‐124 should be modified to account for the increased gas production estimates.

The scope of J‐124 should be modified to account for the increased gas production estimates and future expansion for TPAD and pre‐processed SSO co‐digestion.

Final – May 9, 2017 6‐1 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

6.2.1 Recommended Design Considerations  Consider whether to modify the scope of J‐124 to account for the increased gas production from TPAD and pre‐processed SSO co‐digestion (see Section 3.4.2 and Section 4.2.10).  Gas conditioning equipment design should account for increased moisture in the digester gas from the thermophilic digesters and increased capacity.  As shown on Figure 4‐24, the new Gas Compressor Building is currently shown located on an existing fault. Design evaluation would need to include seismic considerations in determining the final location of and foundation requirements for these facilities.  The Gas Compressor Building needs to accommodate future steam boilers and support facilities due to the additional heating demands for TPAD under P2‐504.  Power Building E should be sited in a similar location to the Gas Compressor Building. Further coordination is recommended during the execution of J‐124 to refine the site layout of these structures.

6.2.2 Future Steam Boiler Coordination The future thermophilic digesters would require additional heat and two new steam boilers are recommended to provide this supplemental heating. The existing steam boilers along with heat recovered from the cogeneration units currently provide heat for the existing digesters. Steam produced from the engine exhaust and boilers provide heat into the heating water system. The hot water is pumped to the digester facility and used as required in sludge heat exchangers to maintain digester heating.

The new steam boilers would operate in series with the existing cogeneration heat and steam boilers. The existing equipment can’t meet the heating demands for TPAD, therefore the new steam boilers, with the use of steam to hot water converters/heat exchangers, would be used to meet the rest of the heating demands. Space near the CenGen facility and boilers is limit and it is recommended the new boilers be located near the digester complex, as part of the new Gas Compressor Building to be designed as part of the J‐124 project. The new steam boilers would require the associated water treatment equipment, including chemical feed system, water softener, deaerator and boiler water feed pumps. The new boiler room would require space for the two steam boilers plus the additional equipment. See Figure 6‐2 for the combined compressor and boiler building layout. The boiler system would need interconnections to the potable water system for boiler feed water, digester gas and natural gas for fuel to the boilers, and treated plant effluent for boiler blowdown cooling.

6.2.3 Construction Cost Estimate A budgetary cost estimate was developed as part of SP‐141 for the Plant No. 2 solids CIP. The total construction cost was estimated to be $23.5 million. 6.3 P2‐500 – DIGESTER REPAIRS P2‐500 will repair the existing digesters to ensure reliable operation until the implementation of TPAD under P2‐504. This project continues current OCSD practice of condition assessment and as‐ needed repairs during regularly scheduled digester cleaning. Drawing upon the recommendations

Final – May 9, 2017 6‐2 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities of P2‐91‐1 and recent observations by the OCSD and BV/BC team, this project ensures adequate budget in the CIP for repairs and replacement of equipment as necessary.

6.3.1 Background 0CSD’s current digester maintenance program services two digesters at a time in each fiscal year. During the regularly scheduled maintenance, digesters are cleaned, valves at or near failure are replaced, OCSD’s corrosion group performs condition assessments prompting repairs of structural damage that could lead to catastrophic failure, and other repairs as needed are implemented. Figure 6‐1 provides a summary of when each of the digesters were built, their cover types, and last major rehab projects (excluding P2‐89 which rehabbed the mechanical and electrical equipment for Digesters I and J). Further details are provided in Appendix G (enclosed Flash Drive) and published as a hard copy at the end of TM‐6.

Figure 6‐1. Digester Summary Indicating Original Construction Date, Major Repair Jobs, Dome Types, and Lining

6.3.2 Project Elements Table 6‐1 summarizes the detailed scope of work for this project.  Rehab or replacement of heat exchangers for sludge recirculation and heating system  Replacement of mixing pumping system  Repair dome wall seal, install dome liners  Replace hot water system  Digester cleaning

Final – May 9, 2017 6‐3 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Table 6‐1. P2‐500 Scope of Work Summary SYSTEM/ CATEGORY ITEM DIGESTERS1 C D E F G H I J K L M N O P Q R S T Sludge Mixing Replace old mixing pumps                   System Sludge Recirculation Rehab or replace heat exchanger                   and Heating System Replace recirculation pumps                   Sludge Transfer Replace bottom sludge transfer pumps                   System Digester Structure Install concrete coating on dome                   and Internal Piping Replace PVC tent liners with concrete                   coating Repair dome to wall seal                   Repair wall penetrations in floor slab and                   digester wall Valve Replacement Replace small valves                   Replace large valves                   Gas Handling System Replace vent PRVs with J‐Tubes                   Hot Water System Replace hot water pumping and piping                   (incl. three‐way valve) Replace the existing temperature sensor                   with digital sensor and connect to SCADA system. Miscellaneous Safety Replace insulation and coating on domes                   Items Safety handrail repairs                   Miscellaneous safety items (e.g. remove                   unused pipe supports and other tripping hazards) Note: 1. Checkmarks safety items.

Final – May 9, 2017 6‐4 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

6.3.3 Sequencing Sequencing has been developed by OCSD staff and the BV/BC team to optimize repair and rehabilitation projects with sequencing of future construction projects. Specific timing and projects are detailed in Appendix G.

6.3.4 Construction Cost Estimate A detailed breakdown of the cost can also be found in the Appendix E (enclosed Flash Drive) and hard copies of the individual facility cost summaries are published at the end of TM‐6. The total estimated construction cost for P2‐500 is $32.7 million, based on December 2016 dollars.

Final – May 9, 2017 6‐5 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Figure 6‐2. Revised Gas Compressor Building Layout to Accommodate Future Steam Boilers

Final – May 9, 2017 6‐6 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

7.0 Implementation Schedule and Sequencing A schedule was developed to plan for the future efforts associated with implementation of the solids expansion projects at Plant No. 2. The details for schedule development are given in Appendix D (enclosed Flash Drive) and published as a hard copy at the end of TM‐6. The schedule reflects the typical budgeting and design‐bid‐build contractual approach used by OCSD. Other contracting methods, such as design build, could be considered for some of the projects. Each project schedule includes estimates for duration of the following activities:

 Project start, development and advertisement of the RFP  Project award, negotiations, and NTP  PDR development  Detailed design  Invitation for bid, award, and construction NTP  Construction, testing, and commissioning

Project start dates and durations for each project stage were presented to OCSD at several workshop: Workshop 6.1.3 on November 15, 2016, Workshop 6.1.3.1 on November 16, 2016, and Workshop 6.1.4 on November 28, 2016. The implementation schedule reflects the outcome of these workshops.

Final – May 9, 2017 7‐1 Biosolids Master Plan TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

Figure 7‐1. Plant No. 2 CIP Implementation Schedule

Final – May 9, 2017 7‐2 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

Table 7‐1, below, outlines the projected project scheduling at Plant No. 2. A detailed version of the table is in Appendix D.

Table 7‐1. A Summary of the Projected CIP Scheduling TASK NAME DURATION START FINISH P2‐500 ‐ INTERIM DIGESTER REPAIRS 136 months 1/2/2017 4/28/2028 Construct 136 months 1/2/2017 4/28/2028 P2‐501 ‐ PERIMETER SCREENING 53 months 7/3/2017 11/30/2021 Planning, Design, And Contract Admin 29 months 7/3/2017 11/29/2019 Construct 24 months 12/2/2019 11/30/2021 P2‐502 ‐ INTERIM PRE‐PROCESSED SSO FACILITY 39 months 2/23/2017 5/29/2020 Planning, Design, And Contract Admin 21 months 2/23/2017 11/29/2018 Construct 18 months 11/30/2018 5/29/2020 P2‐503 ‐ RELOCATE WAREHOUSE AND COLLECTIONS 51 months 1/1/2019 3/31/2023 YARD Planning, Design, And Contract Admin 27 months 1/1/2019 3/30/2021 Construct 24 months 3/31/2021 3/31/2023 J‐124 ‐ DIGESTER GAS HANDLING FACILITIES 102 months 4/1/2017 9/30/2025 Planning, Design, And Contract Admin 54 months 4/1/2017 9/29/2021 Construct 48 months 9/30/2021 9/30/2025 X‐032 – DEWATERED SLUDGE STORAGE AND TRUCK 33 months 7/1/2021 4/1/2024 LOADING REHABILITATION Planning, Design, And Contract Admin 24 months 7/1/2021 6/29/2023 Construct 9 months 6/30/2023 4/1/2024 P2‐504 ‐ TPAD 131 months 7/3/2017 5/31/2028 Planning, Design, And Contract Admin 71 months 7/3/2017 5/30/2023 Construct 60 months 5/31/2023 5/31/2028 P2‐504A ‐ CLASS A BATCH TANKS 155 months 7/3/2017 5/31/2030 Planning, Design, And Contract Admin 71 months 7/3/2017 5/30/2023 Construct 84 months 5/31/2023 5/31/2030 P2‐504B ‐ THICKENED SLUDGE FEED FACILITY 131 months 7/3/2017 5/31/2028 Planning, Design, And Contract Admin 71 months 7/3/2017 5/30/2023 Construct 60 months 5/31/2023 5/31/2028 P2‐504C ‐ FERRIC CHLORIDE FACILITY 64 months 2/1/2035 5/31/2040 Planning, Design, And Contract Admin 40 months 2/1/2035 5/28/2038 Construct 24 months 5/31/2038 5/31/2040 P2‐505 ‐ REPLACE DIGESTERS P, Q, R, S 121 months 4/27/2023 6/1/2033 Planning, Design, And Contract Admin 61 months 4/27/2023 5/31/2028

Final – May 9, 2017 7‐3 Master Plan Biosolids TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities | Orange County Sanitation District

TASK NAME DURATION START FINISH Construct 60 months 6/1/2028 6/1/2033 P2‐506 – PRE‐PROCESSED SSO FACILITY 65 months 7/2/2029 11/30/2034 Planning, Design, And Contract Admin 41 months 7/2/2029 11/29/2032 Construct 24 months 11/30/2032 11/30/2034 P2‐507 ‐ REPLACE DIGESTER‐HOLDERS 132 months 6/1/2027 6/3/2038 (FORMERLY I, J, K) Planning, Design, And Contract Admin 71 months 6/1/2027 4/28/2033 Construct 60 months 6/2/2033 6/3/2038 P2‐508 ‐ DIGESTER DEMOLITION 131 months 7/2/2029 5/31/2040 Planning, Design, And Contract Admin 71 months 7/2/2029 5/30/2035 Construct 60 months 5/31/2035 5/31/2040

Final – May 9, 2017 7‐4 Biosolids Master Plan Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

8.0 Program Cost A budgetary cost estimate was developed for the Plant No. 2 solids CIP. Table 8‐1 presents the cost estimates for each project and the associated markups.

All costs are construction costs based on a Class 4 estimate as defined by the AACE International cost estimate classification system. The following were assumed for the construction cost markups:  Contractor general conditions – 15%  Startup, training, and O&M – 4%  Project level allowance – 50%  Builders risk, liability, auto insurance – 2%  Contractor bonds and insurance – 1.5%

Table 8‐1. Estimate of Probable Construction Cost for Proposed Plant No. 2 Solids Handling CIP (Cost Estimate Basis: December 2016 dollars, unless specified below)

BMP PROJECT CONSTRUCTION COST ESTIMATE (MILLIONS) PROJECT NAME NUMBER LOW (‐30%) MID HIGH (+50%) P2‐500 Interim Digester Repairs $22.9 $32.7 $49.1 P2‐501 Perimeter Screening $0.9 $1.3 $2.0 P2‐502 Interim Pre‐processed SSO $1.8 $2.6 $3.9 Facility P2‐503 Relocate Warehouse and $3.6 $5.2 $7.8 Collections Yard J‐1241 Digester Gas Handling Facilities $16.5 $23.5 $35.3 X‐0322 Dewatered Sludge Storage and $1.8 $2.5 $3.8 Truck Loading Rehabilitation P2‐504 TPAD Project $107.9 $154.1 $231.2 P2‐504A Class A Batch Tanks $18.4 $26.3 $39.5 P2‐504B Digester Feed Facility $8.8 $12.6 $18.9 P2‐504C Relocate Ferric Chloride Facility $1.0 $1.4 $2.1 P2‐505 Replace Digesters P,Q, R, and S $39.8 $56.8 $85.2 P2‐506 Ultimate Pre‐processed SSO $4.1 $5.9 $8.9 Facility P2‐507 Replace Digester‐Holders $27.5 $39.3 $59.0 (Formerly I, J, and K) P2‐508 Digester Demolition $5.2 $7.4 $11.1 ALL TOTAL CIP $260.2 $371.6 $557.8

Notes: 1 Estimates are based on February 2015; 2 Estimates are based on February 2016.

Final – May 9, 2017 8‐1 Master Plan Biosolids Orange County Sanitation District | TM‐6: CIP Project Development for Plant No. 2 Solids Handling Facilities

9.0 References Gerba, C.P., N. Castro‐del Campo, J.P. Brooks, and I.L. Pepper. Exposure and Risk Assessment of Salmonella in Recycled Residuals. Water Science and Technology. 2008.

Higgins, M.J., Y.C. Chen, S.N. Murthy, and D. Hendrickson. (2006a) Examination of Reactivation of Fecal Coliforms in Anaerobically Digested Biosolids. Water Environment Research Foundation Report No. 03‐CTS‐13T, Alexandria, VA.

Higgins, M.J., S.N. Murthy, and Y.C. Chen. (2006 b) Understanding Factors Affecting Conditioning and Dewatering. Water Environment Research Foundation Report No. 01‐CTS‐1, Alexandria, VA.

Higgins, M.J., Y.C. Chen, S.N. Murthy, and D. Hendrickson (2008 a) Evaluation of Bacterial Pathogen and Indicator Densities After Dewatering of Anaerobically Digested Biosolids: Phase II and III. Water Environment Research Foundation Report No. 04‐CTS‐3T. Alexandria, VA.

Higgins, M.J. and S.N. Murthy. (2015) Modifications to Improve Management of Biosolids: Regrowth, Odors, and Sudden Increase in Indicator Organisms. Water Environment Research Foundation Report No. SRSK4T08. Alexandria, VA.

Zaleski, K.J., K.L. Josephson, C.P. Gerba, and I.L. Pepper. Survival, Growth, and Regrowth of Enteric Indicator and Pathogenic Bacteria in Biosolids, Compost, Soil, and Land Applied Biosolids. Journal of Residuals Science and Technology, Vol. 2, No. 1 January 2005.

Final – May 9, 2017 9‐1 Master Plan Biosolids