ORANGE COUNTY SANITATION DISTRICT BIOSOLIDS MASTER PLAN

TECHNICAL MEMORANDUM 7: CIP PROJECT DEVELOPMENT FOR PLANT NO. 1 SOLIDS HANDLING FACILITIES

OCSD PROJECT NO. PS15‐01 reserved. rights

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2015.

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Holding

Veatch

&

Orange County Sanitation District

©Black 9 MAY 2017

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TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities | Orange County Sanitation District

Table of Contents Acronym and Abbreviations List ...... v Executive Summary ...... ES‐1 1.0 Introduction and Background ...... 1‐1 1.1 Purpose ...... 1‐1 1.2 Background Information ...... 1‐1 2.0 Plant No. 1 Post‐Dewatering Facilities Evaluation ...... 2‐1 2.1 Thermal Drying Equipment Types ...... 2‐1 2.2 Partial Drying Alternative ...... 2‐1 2.3 Thermal Drying (Rotary Drum) Alternative ...... 2‐3 2.4 Design Criteria for Rotary Drum Drying System ...... 2‐4 2.5 Rotary Drum Drying System Performance and Sizing ...... 2‐5 2.6 Site Layouts ...... 2‐7 2.7 Net Present Value Cost Evaluation ...... 2‐9 2.7.1 Capital Costs ...... 2‐9 2.7.2 Operating Costs ...... 2‐9 2.7.3 Net Present Value ...... 2‐11 2.7.4 Conclusions and Recommendations ...... 2‐13 3.0 Plant No. 1 Solids Handling Facility Issues Identified and Future Projects/Studies Recommended ...... 3‐1 3.1 Currently Planned CIP Projects ...... 3‐1 3.1.1 Gas Facilities Improvements for Plant No. 1 and Plant No. 2 (J‐124) ...... 3‐1 3.1.2 DAFT Demolition at Plant No. 1 ...... 3‐2 3.2 Solids Handling Process Evaluations and Projects Recommended ...... 3‐2 3.2.1 Plant No. 1 Cake Silo Storage Capacity Evaluation ...... 3‐2 3.2.1.1 Design Criteria and Assumptions ...... 3‐2 3.2.1.2 Storage Capacity Evaluation ...... 3‐3 3.2.1.3 Conclusion ...... 3‐4 3.2.2 Digester Solids Screening Evaluation ...... 3‐4 3.2.3 Digester Capacity Evaluation ...... 3‐5 3.2.4 Sludge Diversion to Plant No. 2 Evaluation ...... 3‐6 3.2.5 Existing Drying Bed Modifications Evaluation ...... 3‐7 3.3 O&M Identified Issues and Solutions ...... 3‐8 3.3.1 Digester Roof Coating Repair ...... 3‐9 3.3.2 Obsolete Boiler Demolition ...... 3‐9 3.3.3 Provide Backup Water Sources for Digester Gas Compressor ...... 3‐9 3.3.4 Assess Condition of and Repair Piping from Ferric Pumps to Digesters ...... 3‐9

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3.3.5 Repair Deficiencies Identified During P1‐100 Work ...... 3‐9 3.3.6 Repair WEMCO Mixing Pumps ...... 3‐9 3.3.7 Existing Hot Water Loop Evaluation ...... 3‐9 4.0 Implementation Schedule and Sequencing ...... 4‐1 5.0 Conclusions and Next Steps ...... 5‐1

See Enclosed Flash Drive for Appendices Appendix A – Process Design Calculation ...... A‐1 Appendix B – SWEET Cost Model Data ...... B‐1 Appendix C – Task 7 Meeting Minutes ...... C‐1 Appendix D – QC Review Affidavits ...... D‐1

Select Published Appendix Appendix A – Process Design Calculation ...... A‐1

LIST OF TABLES Table ES‐1. Plant No. 1 NPV Cost Summary…………………...…………………………………………………………ES‐1 Table 1‐1. Plant No. 1 Solids Flows and Loads ...... 1‐2 Table 2‐1. Plant No. 1 Dryer Conceptual Design Criteria ...... 2‐5 Table 2‐2. Dryer System Capital Cost Summary ...... 2‐9 Table 2‐3. Summary of Annual Sludge Loads Used in SWEET Model ...... 2‐10 Table 2‐4. Summary of Unit Costs and Demands for Utilities and Chemicals ...... 2‐10 Table 2‐5. Characteristics of Flows ...... 2‐11 Table 2‐6. Summary of Costs Associated with Dryer Maintenance and Operation ...... 2‐11 Table 2‐7. Estimated End Use Tipping Fees ...... 2‐11 Table 2‐8. Net Present O&M Costs ...... 2‐11 Table 2‐9. NPV Cost Summary ...... 2‐12 Table 3‐1. J‐124 Biogas Projection Comparison ...... 3‐2 Table 3‐2. Plant No. 1 Cake Silo Storage Design Criteria and Assumptions ...... 3‐3 Table 3‐3. Cake Silo Storage Evaluation Summary ...... 3‐3 Table 3‐4. Plant No. 1 Digester Working Capacities ...... 3‐6 Table 3‐5. Plant No. 1 Future Digester Capacity Evaluation (based on White Paper) ...... 3‐6 Table 4‐1. Implementation Schedule and Sequencing ...... 4‐1

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

LIST OF FIGURES Figure 1‐1. Task Flow for BMP ...... 1‐1 Figure 2‐1. Plant No. 2 Non‐Economic Evaluation ...... 2‐2 Figure 2‐2. IRWD Rotary Drum Dryer ...... 2‐3 Figure 2‐3. Andritz Dryer Process Flow Diagram ...... 2‐3 Figure 2‐4. Rotary Drum Dryer High Quality Granule ...... 2‐4 Figure 2‐5. Plant No. 1 Drying System Process Schematic and Mass Balance ...... 2‐6 Figure 2‐6. Plant No. 1 Drying System Conceptual Layout ...... 2‐7 Figure 2‐7. Plant No. 1 Potential New Dryer Building Location ...... 2‐8 Figure 2‐8. Plant No. 1 Drying NPV Cost Evaluation ...... 2‐12 Figure 3‐1. Screening Option 1 ‐ Screens on Sludge Transfer Loops ...... 3‐4 Figure 3‐2. Screen Option 2 ‐ Screens Upstream of Blend Tanks ...... 3‐5 Figure 3‐3. Plant No. 1 Sludge Drying Beds Location ...... 3‐7 Figure 3‐4. Sludge Drying Bed Sloped Floors ...... 3‐8 Figure 3‐5. Sludge Drying Bed Clogged Trench Drain ...... 3‐8 Figure 3‐6. Example Hot Water Loop Expansion Joint ...... 3‐9 Figure 3‐7. Hot Water Loop Piping Movement ...... 3‐10 Figure 3‐8. Hot Water Loop Piping Insulation Damage ...... 3‐10

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

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

% Percent AQMD Air Quality Management District BMP Biosolids Master Plan BTU British thermal units B&V Black & Veatch BV/BC Team Black and Veatch/Brown and Caldwell Team CDP Criterium Decision Plus cf Cubic foot cf/lb Cubic feet per pound cfd Cubic feet per day cfm Cubic feet per minute CIP Capital Improvement Program CO Carbon monoxide DAFT Dissolved Air Flotation Thickener dt Dry ton dtpd Dry tons per day ea Each °F Degrees Fahrenheit FE/FR Facilities engineering/repair FT Feet/foot FTE Full time equivalent FY Fiscal year gal Gallon GWRS Groundwater Replenishment System HDPE High‐density polyethylene hp Horsepower hr Hour HRT Hydraulic Residence Time I&C Instrumentation and Control IRWD Irvine Ranch Water District kWh Kilowatt‐hour lb Pound ls Lump sum MG Million gallons MGD Million gallons per day min Minute mm Millimeters MMBtu Million British thermal units N Nitrogen NFPA National Fire Protection Agency NPV Net present value

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O&M Operations and maintenance OCSD Orange County Sanitation District ppd Pounds per day R&R Restoration and replacement RFP Request for Proposal RTO Regenerative thermal oxidizer sf Square feet/foot SWEET Solid‐Water‐Energy‐Evaluation Tool TM Technical Memorandum TPODS Treatment Plant Operational Data Summary TS Total solids TSS Total suspended solids TWAS Thickened waste activated sludge U.S. United States VS Volatile solids VSR Volatile solids reduction VSS Volatile Suspended Solids WAS Waste activated sludge

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

Executive Summary This Technical Memorandum (TM) 7, CIP Project Development for Plant No. 1 Solids Handling Facilities, presents a post‐dewatering facilities evaluation and the development of potential solids handling capital improvement program (CIP) projects and/or evaluations. This work was conducted under Task 7 of Orange County Sanitation District (OCSD) Project No. PS15‐01, Biosolids Master Plan (BMP).

This document is organized to include the following sections:  Section 1: Introduction and Background  Section 2: Plant No.1 Post –Dewatering Facilities Evaluation  Section 3: Plant No.1 Solids Handling Facility Problems Identified and Future Project Development  Section 4: Implementation Schedule and Sequencing  Section 5: Conclusions and Next Steps

The following are highlights of each section in TM‐7.

Section 1 (Introduction and Background) This section presents background on the BMP and provides the context for TM‐7 and how it relates to the other TMs. A summary of the flows and loads from TM‐1 is provided, which forms the basis for the post‐dewatering facilities evaluation.

Section 2 (Plant No. 1 Post –Dewatering Facilities Evaluation) This section presents the post‐dewatering facilities evaluation at Plant No.1. Three alternatives were considered: (1) no post‐dewatering facilities, (2) partial drying with paddle dryers, and (3) thermal drying using rotary drum dryers. Partial drying was screened out due to non‐economic considerations. Capital and operations and maintenance (O&M) costs were then developed for a rotary drum thermal drying system in order to compare the net present value (NPV) between no drying or complete thermal drying. The evaluation showed that the no drying alternative had the lower NPV cost as shown in Table ES‐1. Also, thermal drying has some non‐economic disadvantages such as higher onsite O&M requirements, greater complexity, safety concerns, and challenging site considerations. Therefore, no post‐dewatering facilities are recommended at Plant No. 1.

Table ES‐1. Plant No. 1 NPV Cost Summary ALTERNATIVE CAPITAL COST O&M NPV No drying ‐‐ $147.6M $147.6M Thermal Dryer $52.7M $109.1M $161.8M

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

Section 3 (Plant No. 1 Solids Handling Facility Issues Identified and Future Projects/Studies Recommended) This section captures the Plant No. 1 solids handling facilities issues identified by OCSD staff, potential solutions to those problems, and future project development. A list of potential CIP projects and evaluations was developed and discussed with OCSD staff. The CIP projects identified do not need to be captured in the BMP because they are already accounted for in OCSD’s CIP program. Some potential projects that address issues identified by OCSD operations staff do not need to be captured in the BMP because they are small enough to be resolved through other OCSD programs. The following future solids handling evaluations are recommended to determine if a CIP project may be warranted:  Digester Solids Screening Evaluation  Digester Capacity Evaluation  Sludge Diversion Pipeline to Plant No. 2 Evaluation  Existing Drying Bed Modifications Evaluation

Section 3 describes these issues, identifies potential solutions, and recommends further study.

Section 4 (Implementation Schedule and Sequencing) In this section, a preliminary implementation schedule and sequencing plan was developed for the five evaluations identified in Section 3. For each evaluation, predecessor activities, estimated start dates, and durations are provided.

Section 5 (Conclusions and Next Steps) In this section, conclusions from the post‐dewatering evaluation and CIP project development are summarized. Since post‐dewatering at Plant No. 1 is not being recommended, no further steps are required. It is recommended that the five solids handling evaluation identified in Section 3 be completed to determine if any additional CIP projects are warranted.

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

1.0 Introduction and Background 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 to evaluate existing OCSD solids‐handling facilities, study solids‐treatment alternatives, and recommend future capital facilities improvements. The BMP report will be composed of nine technical memoranda and supporting information. This document presents Technical Memorandum (TM) 7: CIP Project Development for Plant No. 1 Solids Handling Facilities. As part of the CIP project development, Plant No. 1 post‐dewatering facilities were evaluated. 1.1 PURPOSE The purpose of TM‐7 is to develop CIP projects for the Plant No. 1 solids handling facilities based on the following: 1. A post‐dewatering facilities evaluation, which is used to recommend whether or not to add new thermal drying using a rotary drum dryer. 2. A review of solids handling facility issues identified by OCSD staff and currently planned CIP projects. 1.2 BACKGROUND INFORMATION Six TMs were previously submitted and reviewed by 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, TM‐5 High Strength Organic Waste Co‐Digestion Evaluation, and TM‐6 CIP Project Development for Plant No. 2. TM‐1 and TM‐2 form the baseline for the project as a whole and were used to provide background and context for this TM. TM‐3 summarized market research and an evaluation conducted to determine the biosolids products with the best market potential. Those selected products served as the starting point for the Plant No. 2 post‐dewatering facilities evaluation performed in TM‐4. In this TM‐7, a post‐dewatering facilities evaluation was performed for Plant No. 1. In addition, other potential Plant No. 1 biosolids CIP projects and evaluations were developed. A summary of the task flow for the BMP is provided on Figure 1‐1.

Figure 1‐1. Task Flow for BMP

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

Digested biosolids quantities that were used to develop a conceptual design for potential post‐ dewatering facilities were based on values identified in TM‐1 for Condition 1. Table 1‐1 summarizes these values.

Table 1‐1. Plant No. 1 Solids Flows and Loads SOLIDS FLOW CONDITION VALUE Total undigested sludge Annual average 408,000 dry solids, pounds per day Peak 15‐day 491,000 (ppd) Maximum day 654,000 Total digested sludge dry Annual average 218,583 solids, ppd Peak 15‐day 262,409 (assumes 60% VSR reduction) Maximum day 350,060

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

2.0 Plant No. 1 Post‐Dewatering Facilities Evaluation A detailed post‐dewatering facilities evaluation for Plant No. 1 was conducted, which is similar to the post‐dewatering evaluation performed for Plant No. 2 in TM‐4. The base case alternative is no post‐dewatering facilities at Plant No. 1. The purpose of the evaluation was to determine if there are economic incentives and non‐economic drivers for adding post dewatering facilities. 2.1 THERMAL DRYING EQUIPMENT TYPES Thermal drying systems evaporate water from dewatered biosolids to produce a dried product that can be used as a fertilizer or fuel source. Drying systems use different heat transfer methods for conveying heat to the biosolids for water evaporation:

 Conduction systems transfer the heat from the source (typically steam or heated oil) through a metal surface to the solids. A paddle dryer is an example of a conduction system. Conduction systems are often called “indirect” dryers because the biosolids do not come in direct contact with the heat medium.  Convection systems use hot gasses in direct contact with the solids for water evaporation. Examples of convection systems include the rotary drum dryer and the belt dryer. Convection systems are often called “direct” systems because the biosolids comes in direct contact with the hot gases.

Both types have advantages and disadvantages. For example, a conduction system has significantly less exhaust air to treat than a convection system and is typically a smaller footprint than a similarly sized convection system. But conduction systems like paddle dryers typically produce an irregular shaped product with a relatively high concentration of fines, which is undesirable for marketable products. However, some convection systems are capable of producing uniform granules with low dust concentrations. Conduction systems typically operate at temperatures in the 390°F to 450°F range while convection systems can operate in the 300°F to 1,000°F range, depending on the specific dryer. 2.2 PARTIAL DRYING ALTERNATIVE The Plant No. 2 analysis of post‐dewatering systems in TM‐4 focused on partial drying and thermal drying. That analysis is also applicable for Plant No. 1.

Partial drying would involve thermally drying a portion of the biosolids, then blending the dried product with dewatered biosolids to reduce the mass to be transported for land application. The non‐economic evaluation of these two post‐dewatering options is shown on Figure 2‐1 and demonstrates that partial drying is the lowest ranked alternative. There are many unknowns associated with the process as it has not been applied in the U.S., and the primary benefit is the reduction of mass for transport. As shown on Figure 2‐1, criteria such as Operability/ Maintainability/Reliability, Safety, and End Use Market Diversity ranked comparatively lower for the partial drying alternative. For these reasons partial drying was not considered to be a viable process for Plant No. 1. During the workshop held on December 20, 2016, OCSD concurred with the recommendation to not carry the partial drying alternative forward for further evaluation.

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

Figure 2‐1. Plant No. 2 Non‐Economic Evaluation

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

2.3 THERMAL DRYING (ROTARY DRUM) ALTERNATIVE Of the different types of thermal drying systems available on the market, the rotary drum dryer is best suited for producing the high quality product identified during the market assessment summarized in TM‐3. It has a proven track record with biosolids and can be sized to process OCSD’s total biosolids production at Plant No. 1.

The rotary drum dryer is a continuous feed system capable of processing large quantities of biosolids in a single train. Single train systems can be sized to handle from less than 10 dry tons per day (dtpd) up to 90 dtpd. The drum dryer has been in use in the United Figure 2‐2. IRWD Rotary Drum Dryer States since 1926 with the development of the Milwaukee facility and is used by many of the largest installations in the U.S., such as Milwaukee, New York, Baltimore, Boston, Louisville, Nashville, and Jacksonville, as well as many medium size installations such as the Encina Wastewater Authority. The Irvine Ranch Water District (IRWD) is currently constructing a new rotary drum drying facility as shown in Figure 2‐2. There are more than 20 installations in the United States and more than 100 worldwide.

Rotary drum drying systems include the rotary drum, with direct gas heating and a recycle feed system. A process flow diagram for a typical system supplied by Andritz is shown in Figure 2‐3.

Recirculated Air Venturi Comb. Air Scrubber To RTO Fuel V Drum Dryer Polycyclone Wastewater Furnace Pre- Process Fan Separator Condenser Exhaust Fan

Pellets Wastewater Wastewater To RTO Mixer V

Trash > 10mm 4 to 10mm 2 to 4mm Screen Fugitive Dust Fines Collector V Diverter Crusher Valve

Cake

Pellet Wet Cooler Material Recycle Bin Bin

V Vent to Dust Collector Pneumatic Transporter to Silo

Figure 2‐3. Andritz Dryer Process Flow Diagram

Final ‐ May 9, 2017 2‐3 Biosolids Master Plan TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities | Orange County Sanitation District

In this process, dried recycled product is coated with dewatered cake in a mixer, before entering the rotary drum dryer. Heated process gas flows through the drum, heating the pellets and absorbing evaporated moisture while the rotation of the drum keeps the material in motion. At the exit of the drum, the density of the dried product is low enough that it becomes entrained in the process gas flow and is carried to a pre‐separator and cyclone, where the pellets are separated and conveyed to a screen. In the screen, oversized material and undersized material are separated from properly sized pellets. The oversized material is crushed and returned to the mixer, along with fines and a portion of properly sized pellets. This dry product is then recoated with dewatered cake and sent back through the dryer. A portion of the properly sized pellets downstream of the screen is not recycled, but is cooled in a product cooler and conveyed to storage as finished product.

Downstream of the cyclone, the process gas flows through a wet scrubber condenser for removal of particulates and moisture. The gas is then returned to the furnace to repeat the cycle. During operation, oxygen concentrations in the process gas are typically below five percent. A portion of the process gas stream is removed and directed to a high efficiency wet venturi scrubber to remove fine particulate. This blow‐down gas is then treated through a regenerative thermal oxidizer (RTO) for odor control.

Oxygen levels throughout the dryer system are maintained at a concentration below levels that may cause fires and explosions. These systems have extensive temperature and carbon monoxide (CO) monitoring systems throughout. Product is typically stored in silos prior to discharge into trucks. Product storage should also be monitored for temperature and CO. Nitrogen (N) inerting capability is recommended for silo storage systems in the event a smoldering fire is detected.

The primary advantages of the rotary drum dryer are the high quality and uniformity of the product and the high throughput capacity. The finished granule will typically range from 2 to 4 millimeters (mm) in diameter and will look similar to manufactured chemical fertilizers. Screening can be adjusted to control particle size and match the users’ needs. The hardness of the granules and screening both help to reduce the formation of dust during product handling. A photograph of a typical high quality granule from a rotary drum dryer is given on Figure 2‐4. Figure 2‐4. Rotary Drum Dryer High Quality Granule

The key disadvantage of the drum dryer is the complexity of the system. This type of system requires the continuous presence of operations staff to monitor the system and regular shutdowns for maintenance. 2.4 DESIGN CRITERIA FOR ROTARY DRUM DRYING SYSTEM As noted in Sections 2.2, partial drying technology was not recommended for post dewatering at Plant No.1. However, rotary drum drying is a suitable technology and was used to develop the requirements for a post‐dewatering facility at Plant No. 1. This section summarizes the preliminary

Final ‐ May 9, 2017 2‐4 Biosolids Master Plan Orange County Sanitation District | TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities design information for the drying system. Development was based on the 2035 loadings identified in Section 1.0. Figure 2‐5 on the following page shows a process flow schematic for the drying system as well as a mass balance based on the 2035 loadings. The detailed process calculations are given in Appendix A (enclosed Flash Drive) and published as a hard copy at the end of TM‐7. 2.5 ROTARY DRUM DRYING SYSTEM PERFORMANCE AND SIZING Preliminary sizing was based on the use of an Andritz DDS80 drying system. Several sizes were evaluated and the DDS80 provided the optimum size to meet current and future processing needs. The drying system was sized based on continuous operation with one unit always in standby mode. It is anticipated that a dryer train would be operated continuously for two to three weeks and then rotated out of service for preventative maintenance. Table 2‐1 shows the conceptual design criteria developed for the system.

Table 2‐1. Plant No. 1 Dryer Conceptual Design Criteria

PARAMETER DESIGN CRITERIA Cake feed total solids (TS), percent (%) 25 Dried product TS, % 92 Hours of operation Continuous Average power consumption/train, horsepower (hp) 920 Average energy requirement, British Thermal Unit per 1,600 (includes RTO) pound (BTU/lb) water evaporated Total energy demand, % of annual biogas produced 69 Operating + Standby units required Number of Units % utilization @ average Future (2035) 2+1 75 Ultimate 3+1 78

Final ‐ May 9, 2017 2‐5 Biosolids Master Plan TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities | Orange County Sanitation District

Figure 2‐5. Plant No. 1 Drying System Process Schematic and Mass Balance

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2.6 SITE LAYOUTS The rotary drum dryer systems would be housed in a new building located as close to the existing dewatering facility as possible. A conceptual building layout was developed based on providing capacity to accommodate the future (2035) conditions with three drying trains and space for a future train to meet the ultimate loading conditions. The building would require approximately 34,000 square feet (sf) of space, as shown in Figure 2‐6. Figure 2‐7 shows a potential location for the facility on the Plant No. 1 site, adjacent to the existing dewatering and truck loadout facilities. As suggested by the figure, it appears challenging to locate the dryer building close to the existing dewatering facilities. Also, the dryer would occupy area on the site that may be needed for future facilities.

Figure 2‐6. Plant No. 1 Drying System Conceptual Layout

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

Figure 2‐7. Plant No. 1 Potential New Dryer Building Location

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2.7 NET PRESENT VALUE COST EVALUATION Capital and operating costs were developed for the conceptual Plant No. 1 dryer system to evaluate the net present value (NPV) of the Thermal Drying option and the “No Drying” option. Details of the NPV cost evaluation are provided in the following sections.

2.7.1 Capital Costs Capital costs were estimated based on the dryer system conceptual design and layout presented in the previous sections. A summary of the capital costs is provided in Table 2‐2.

Table 2‐2. Dryer System Capital Cost Summary UNIT COST COST ITEM UNIT TOTAL ($/UNIT) EQUIPMENT Overhead Crane 1 lump sum (ls) $100,000 $100,000 Drying System 3 each (ea) $10,000,000 $30,000,000 Equipment Installation 1 ls $6,020,000 $6,020,000 BUILDING Building 34,000 sf $200 $6,800,000 HVAC 1 ls $30,000 $30,000 Allowance for cake delivery modifications 1 ls $1,000,000 $1,000,000 SUBTOTAL $43,950,000 INDIRECT COSTS Electrical and Instrumentation and Control (I&C) 1 ls $6,593,000 $6,593,000 Sitework 1 ls $2,198,000 $2,198,000 TOTAL $52,741,000

2.7.2 Operating Costs A yearly O&M cost was calculated based on the projected sludge loads into the dryer facility from 2023 to 2043. These sludge loads were determined based on data from 2014 Treatment Plant Operational Data Summary (TPODs) and 2035 Condition 1 projected loads presented in OCSD’s White Paper. These data were used to create a linear model to extrapolate the yearly inputs of primary sludge, waste activated sludge (WAS), and trickling filter sludge from 2023 to 2043. Table 2‐3 presents the estimated annual loads used in Brown and Caldwell’s Solids Water Energy Evaluation Tool (SWEET) program. Total solids and volatile solids were assumed to be the same for each year, which are presented in Table 2‐5.

O&M costs were based on the same dose and unit costs presented in TM‐4, except for potable water and composting. The source of potable water is different for the different plants. Also, the cost for composting was changed based on recent conversations with OCSD. A summary of costs and doses are presented in Table 2‐4 and Table 2‐6. Finally, Table 2‐7 indicates the fees associated with the different end use options.

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

Table 2‐3. Summary of Annual Sludge Loads Used in SWEET Model YEAR PRIMARY SLUDGE (PPD) WAS (PPD) TRICKLING FILTER (PPD) 2023 245,378 85,874 14,103 2024 249,807 87,049 14,139 2025 254,235 88,223 14,175 2026 258,664 89,398 14,211 2027 263,092 90,573 14,247 2028 267,521 91,748 14,284 2029 271,950 92,923 14,320 2030 276,378 94,098 14,356 2031 280,807 95,273 14,392 2032 285,235 96,447 14,428 2033 289,664 97,622 14,465 2034 294,092 98,797 14,501 2035 298,521 99,972 14,537 2036 302,950 101,147 14,573 2037 307,378 102,322 14,609 2038 311,807 103,497 14,646 2039 316,235 104,671 14,682 2040 320,664 105,846 14,718 2041 325,092 107,021 14,754 2042 329,521 108,196 14,790 2043 333,950 109,371 14,827

Table 2‐4. Summary of Unit Costs and Demands for Utilities and Chemicals UTILITIES (WATER AND POWER) COSTS Imported Electricity ($/kilowatt‐hour (kWh)) $0.10 Exported Electricity ($/kWh) $0.04 Dryer power consumption (kwh/dry tons (dt)) 301.40 Natural Gas Unit Cost ($/MMBtu) $4.66 Natural Gas for Dryer (MMBtu/dt) 9.33 Potable water ($/748 gallons (gal)) $2.94 Plant water ($/million gallons (MG)) $61.22 Dryer Water Consumption (gallons/dt) 22,459 CHEMICAL COSTS Centrifuge Thickening Polymer Unit Cost ($/lb) $2.65 Centrifuge Thickening Polymer Dose (lb/dry ton solids) 5 Centrifuge Dewatering Polymer Unit Cost ($/lb) $2.65 Centrifuge Dewatering Polymer Dose (lb/dry ton solids) 20

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Table 2‐5. Characteristics of Flows PARAMETER PRIMARY SLUDGE WAS TRICKLING FILTER Total solids (%) 4.1 1.0 1.9 Volatile solids (%) 80 80 80

Table 2‐6. Summary of Costs Associated with Dryer Maintenance and Operation CRITERIA COSTS Maintenance Staff incl. benefits ($/hr) $59.22 Operations Staff incl. benefits ($/hr) $70.87 Full time employee (FTE)/shift (maintenance) ‐ dryer 0.33 FTE/shift (operations) ‐ dryer 2 Shifts/day 3 Percent for annual maintenance ‐ dryer 2% Restoration and Replacement (R&R) (20 years from start) $3,602,000

Table 2‐7. Estimated End Use Tipping Fees PROCESS END USE FEE Land Application CA ($/Wet ton) $36.00 On Site Land Application AZ ($/Wet ton) $45.00 Thermal Drying Bulk Horticulture ($/Wet ton) $26.00 Fertilizer Blending ($/Wet ton) $6.00 Class B Cake Land Application AZ ($/Wet ton) $55.00 Compost to Class A ($/Wet ton) $56.00

Based on the assumptions provided in the previous tables, a net present O&M cost was developed using the SWEET model for both the No Drying and Thermal Drying Options and is summarized in Table 2‐8. Detailed SWEET model data is given in Appendix B. The costs assume plant water will be used (in lieu of potable water). As shown in Table 2‐8, the net present O&M cost for Thermal Drying is $38.5M lower than that for No Drying. The maintenance and operation costs for thermal drying are higher than for not drying; however, the hauling costs for thermal drying are substantially lower than for not drying due to the lower water content in the dried product.

Table 2‐8. Net Present O&M Costs OPTION NET PRESENT O&M COST No Drying $147,634,000 Thermal Drying $109,087,000

2.7.3 Net Present Value The Plant No. 1 dryer system design criteria, capital, and operating costs were input into the SWEET model to determine the NPV for the Thermal Drying Option and No Drying Option.

Final ‐ May 9, 2017 2‐11 Biosolids Master Plan TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities | Orange County Sanitation District

The NPV evaluation is based on the following assumptions:  Escalation rate = 3.5%  Discount rate = 4%  Midpoint of construction = 2023  Life cycle duration = 2025‐2045 (20 years)

The results of the SWEET model output are show in Table 2‐9 and on Figure 2‐8.

Table 2‐9. NPV Cost Summary PROCESS CAPITAL COST O&M NPV No drying ‐‐ $147,634,000 $147,634,000 Thermal Dryer $52,741,000 $109,087,000 $161,828,000

$180 Capital $160 O&M PV NPV $140

$120

$100

Millions $80

$60

$40

$20

$0 No Drying Thermal Drying

Figure 2‐8. Plant No. 1 Drying NPV Cost Evaluation

Final ‐ May 9, 2017 2‐12 Biosolids Master Plan Orange County Sanitation District | TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities

2.7.4 Conclusions and Recommendations The SWEET evaluation of post‐dewatering alternatives for Plant No. 1 was presented to OCSD at a workshop on December 20, 2016. As shown in Figure 2‐8, the NPV for the Thermal Drying Option is approximately $14.2M higher than the NPV for the No Drying Option. While thermal drying has a lower O&M cost due to reduced hauling, the capital cost of the equipment increases the NPV above that of the No Drying Option.

In addition, the results of the noneconomic CDP evaluation of alternatives reported for Plant No. 2 in TM‐4 are also applicable for Plant No. 1. These results are given graphically in Figure 2‐1 (Section 2.2). Although thermal drying will increase product diversity, there are several non‐ economic disadvantages associated with thermal drying such as increased maintenance, equipment complexity, and safety concerns, which make this option less desirable.

Finally, it is challenging to find sufficient site area in close proximity to the existing solids dewatering facilities and the new building would eliminate valuable space for potential future facilities. Since there was not an economic incentive and there are several non‐economic disadvantages, thermal drying was not recommended for Plant No. 1 during the workshop held on December 20, 2016. OCSD concurred with this recommendation.

Final ‐ May 9, 2017 2‐13 Biosolids Master Plan Orange County Sanitation District | TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities

3.0 Plant No. 1 Solids Handling Facility Issues Identified and Future Projects/Studies Recommended A list of potential Plant No. 1 solids handling CIP projects and recommended evaluations was developed through review of OCSD’s current CIP project list, Plant No. 1 site walks with plant operations staff, and meetings with OCSD staff. Projects currently listed in OCSD’s CIP are described in Section 3.1 and are not carried forward for the BMP CIP. The screened list of BMP CIP projects is provided in Section 3.2. Lastly, a list of O&M issues identified by OCSD O&M staff, but not included in the final BMP CIP list is provided in Section 3.3. 3.1 CURRENTLY PLANNED CIP PROJECTS The following projects were previously identified in the Fiscal Year (FY) 2016‐2018 OCSD Proposed Budget for Plant No. 1. Since they have already been accounted for in OCSD’s planning, they will not be further discussed in the BMP.

3.1.1 Gas Facilities Improvements for Plant No. 1 and Plant No. 2 (J‐124) The Plant No. 1 gas facilities consist of low pressure gas collector piping and storage, gas compressors, gas dryers and a high pressure gas distribution piping. These facilities are used to collect and pressurize digester gas for fueling the Central Generation Power Facilities. According to OCSD, the gas compressor system’s mechanical equipment has reached the end of its service life and the gas facilities are in need of upgrading to improve safety and to meet current and future requirements of the Air Quality Management District (AQMD) and the National fire Protection Association (NFPA). The J‐124 Plant No. 1 improvements project will install new gas compressors and gas dryers and replace the high pressure flare system with a low pressure system. Sections of the gas piping need modification to control condensation and corrosion. The existing gas compressor building will be demolished and replaced at a new location on site.

The gas facilities improvements planned for J‐124 were recommended in project SP‐141, Gas Facilities Study for Plants 1 and 2. In SP‐141, future gas production projections were evaluated to determine if the gas facilities should be upgraded to handle future demands. Since the completion of SP‐141, OCSD’s Solids Loading Projections White Paper has been updated to include the most recent plant performance and future flow and load projections. As part of TM‐6 the gas projections in SP‐141 were compared to the gas projections based on the current loadings including impacts due to food waste imports at Plant No. 2 (see TM‐6, Table 4‐13, Table 4‐14 and Table 4‐16). A summary of the comparison is provided in Table 3‐1. As shown in the table, current loadings at Plant No. 1 for this BMP are lower than the SP‐141 design basis. Therefore, SP‐141 recommendations for Plant No. 1, to be constructed under Project J‐124 remain unchanged.

Final ‐ May 9, 2017 3‐1 Biosolids Master Plan TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities | Orange County Sanitation District

Table 3‐1. J‐124 Biogas Projection Comparison SP‐141 DESIGN WHITE PAPER DESIGN CRITERIA BASIS BASIS Projection Year 2045 2035 (Condition 1) Annual Average Solids Production, ppd 391,260 405,727 Volatile Solids Reduction (VSR), % 65 58 Biogas Production Rate, cubic feet per pound (cf/lb) Volatile 15.5 15.5 Solids (VS) destroyed Biogas Production (Annual Average Condition), cubic feet 2,156 1,840 per day per cubic feet per minute (cfm) Peaking Factor (Peak Hour to Annual Average) 1.5 1.5 Biogas Peak Hour Design Capacity, cfm 3,500 cfm 2,760

At the time of this TM, the RFP for J‐124 is expected to be released in April 2017. Per the FY 2016‐ 2018 Proposed Budget, the total project cost (current dollars) is estimated to be $87.9M (combined cost for Plant Nos. 1 and 2).

3.1.2 DAFT Demolition at Plant No. 1 The Dissolved Air Flotation Thickener (DAFT) Demolition Project would remove most of the DAFT facilities at Plant No. 1 including the DAFT structure, polymer building, and 10‐inch thickened waste activated sludge (TWAS) line in the gallery. A portion of the building containing an electrical room, satellite control room, laboratory, and restrooms will remain. The project is currently in the pre‐planning stage by OCSD staff and is estimated to start in year 2020 after P1‐101 is completed and the thickening centrifuges are reliably in operation.

The estimated project cost (in today’s dollars) prepared by OCSD is approximately $3.7M. The DAFT Demolition Project is not further discussed in the BMP because it will be further evaluated and included in OCSD’s 2017 Facility Master Plan. 3.2 SOLIDS HANDLING PROCESS EVALUATIONS AND PROJECTS RECOMMENDED This section reviews the major solids handling processes, evaluates the issues requested by the BMP scope of work and identified by OCSD Operations staff, and makes recommendations for future projects or additional evaluations.

3.2.1 Plant No. 1 Cake Silo Storage Capacity Evaluation During a project meeting on November 30, 2016, OCSD requested verification that the cake silo storage has adequate capacity for future conditions. B&V reviewed and updated the P1‐101 cake storage evaluation with the OCSD White Paper future loadings to confirm that adequate cake storage will be available.

3.2.1.1 Design Criteria and Assumptions The design criteria and assumptions listed in Table 3‐2 were made in order to evaluate the cake silo storage capacity.

Final ‐ May 9, 2017 3‐2 Biosolids Master Plan Orange County Sanitation District | TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities

Table 3‐2. Plant No. 1 Cake Silo Storage Design Criteria and Assumptions DESIGN CRITERIA ASSUMPTIONS SOURCE Design Year 2035 TM‐1 Loadings, Condition 1 Design Flow 125 mgd TM‐1 Loadings, Condition 1 Digested Sludge TSS 216,593 lb/d TM‐1 Loadings, Condition 1 Solids Capture Rate (Dewatering Centrifuge) 97 % TM‐1 Loadings, Condition 1 Dewatered Cake 210,095 lb/day TM‐1 Loadings, Condition 1 Dewatered Cake Specific Weight 64 lb/cf TM‐1 Loadings, Condition 1 Usable Cake Silo Volume (ea.) 12,100 cf P1‐101 Evaluation and Drawing Calculations1 Number of Cake Silos 4 Assumed all silos in service Storage Duration Required 3.5 days P1‐101 Evaluation Note: 1. The 12,100 cf volume assumed in the P1‐101 evaluation was verified by independently calculating the storage volume based on the P1‐34‐2 drawings. A volume of 12,100 cf is achieved once the average level in the silos is 4’‐7” below the bottom of the silo roofs. Level setpoints were not available at the time to confirm the programmed maximum silo levels.

3.2.1.2 Storage Capacity Evaluation OCSD staff requested that B&V confirm the silos are capable of storing a minimum of 3.5 days of cake produced during the year 2035 loading conditions listed in TM‐1 (Condition 1) and at a flow rate of 125 mgd. The 3.5 days represents the estimated time between truck loadouts over a holiday weekend (i.e., truck loadout stops on Friday afternoon and continues on Tuesday morning). The storage capacity evaluation was performed assuming the silos are empty at the start of the 3.5 days. The calculations for this evaluation are included in Appendix A (enclosed Flash Drive) and published as a hard copy at the end of TM‐7. The results are given in Table 3‐3.

A range of cake solids concentrations (25%‐30%) is given because the performance of the new dewatering centrifuges has not been established. A minimum of 3.5 days of storage is provided for the full range of solids concentrations evaluated. Cake solids would have to drop to approximately 23.7% solids concentration to jeopardize the requirement of 3.5 days of storage.

Table 3‐3. Cake Silo Storage Evaluation Summary DEWATERED CAKE THICKNESS 23.74% 25% 26% 27% 28% 29% 30% Total Cake Silo Storage Volume (cf) 48,400 48,400 48,400 48,400 48,400 48,400 48,400 Wet Cake (lb/d) 885,029 840,381 808,059 778,130 750,340 724,466 700,317 Wet Cake (tons/d) 443 420 404 389 375 362 350 Wet Cake (cf/d) 13,829 13,131 12,626 12,158 11,724 11,320 10,942 Wet Cake (cf/min) 9.6 9.1 8.8 8.4 8.1 7.9 7.6 Storage Duration (min) 5,040 5,308 5,520 5,732 5,945 6,157 6,369 Storage Duration (days) 3.50 3.69 3.83 3.98 4.13 4.28 4.42

Final ‐ May 9, 2017 3‐3 Biosolids Master Plan TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities | Orange County Sanitation District

3.2.1.3 Conclusion Based on the results of this evaluation, no additional cake storage is required at this time for the year 2035 (Condition 1) conditions provided in TM‐1, and no cake storage project is necessary.

3.2.2 Digester Solids Screening Evaluation OCSD operations staff have identified a fundamental problem with the anaerobic digesters in terms of grit and rag accumulations that are detrimental to digester performance. OCSD maintenance staff periodically clean the Plant No. 1 digesters to optimize performance. During the cleaning process, after the dirty digester is initially drained, the remaining digested sludge is transferred to one of the digesters in service. Sludge transferred from the side of the digester contains rags that tend to form a mat at the liquid level surface, while sludge transferred from the bottom of the digester contains grit that reduces the active volume. Hence these materials and the problems they cause are being transferred to clean digesters. Rags tend to plug the overflows on the active digesters, requiring maintenance staff to plunge the overflows frequently. OCSD staff would like to remove the rags and grit so they do not inhibit performance of the digesters and create added maintenance headaches.

In order to either prevent grit and rags from accumulating in the digesters in the first stage and/or to remove grit and rags during digester cleaning, two potential solids screening options were identified during discussions with OCSD staff. Option 1 includes in‐line screens (i.e., Huber strain press) in the transfer loops to capture debris before it’s transferred to the clean digesters. Option 2 includes screens upstream of the Sludge Blending Tanks. Options 1 and 2 are illustrated in Figure 3‐1 and Figure 3‐2, respectively.

It is recommended that OCSD perform a formal evaluation of the potential for new sludge Figure 3‐1. Screening Option 1 ‐ Screens on Sludge screening facilities. If the evaluation recommends Transfer Loops new sludge screens, a project should be added to the Plant No. 1 CIP in the future.

Final ‐ May 9, 2017 3‐4 Biosolids Master Plan Orange County Sanitation District | TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities

Figure 3‐2. Screen Option 2 ‐ Screens Upstream of Blend Tanks

3.2.3 Digester Capacity Evaluation It is noted that per the latest projections in the White Paper, the Plant No. 1 digesters will be at capacity in the year 2035, based on the following analysis. The projections assume IRWD is no longer sending IRWD solids to OCSD, the new P1‐101 centrifuges thicken to 28 percent solids, and no food waste receiving is added to Plant No. 1. OCSD staff has also indicated their desire for Digesters 5 and 6 to remain as digested sludge holding tanks.

Final ‐ May 9, 2017 3‐5 Biosolids Master Plan TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities | Orange County Sanitation District

Per the TM‐1, Condition 1, the following assumptions and design criteria have been established and are based on a 15‐day peaking factor of 1.2 per TM‐1:

 Design Year: 2035 Table 3‐4. Plant No. 1 Digester Working Capacities  Peak 15‐Day Flow to Digesters: 0.94 million gallons per day WORKING (MGD) DIGESTER CAPACITY (MG)  Working Digester Capacity (all 10 digesters in operation): 7 1.38 19.24 million gallons (MG) 8 1.38  Minimum Hydraulic Residence Time (HRT) for Class B 9 2.06 sludge: 17 days (peak 15‐day with 2 digesters out of 10 2.06 service) 11 2.06  Peak 15‐Day Volatile Suspended Solids (VSS) Load to 12 2.06 Digesters = 376,682 lb/d 13 2.06

The digester working capacities provided in OCSD’s 2009 Facility 14 2.06 Master Plan are shown in Table 3‐4. 15 2.06 16 2.06 If all the digesters are in operation, the HRT is approximately 20 10 TOTAL TOTAL = 19.24 days; however, OCSD routinely cleans the digesters and it’s fairly common to have one or two digesters out of service at any time. Therefore, OCSD has established that the minimum digester HRT must be met with 2 digesters out of service. The HRT was calculated for different pairs of digesters being out of service in Table 3‐5.

As shown in Table 3‐5, the HRT predicted for year 2035 exceeds the 17‐day threshold when more than two digesters are out of service.

Table 3‐5. Plant No. 1 Future Digester Capacity Evaluation (based on White Paper)

WORKING WHITE PAPER, CONDITION 1 CONDITION VOLUME FLOW VSS LOADING HRT 3 (MG) (MGD) (LB/D/FT ) (DAYS) All Digesters in Service 19.24 0.94 0.15 20.56 Digesters 7 and 9 Out of Service 15.80 0.94 0.18 16.88 Digesters 10 and 11 Out of Service 15.12 0.94 0.19 16.15

Based on the brief evaluation performed above, it is recommended that OCSD conduct a comprehensive evaluation of future digester capacity requirements. In order to provide an accurate assessment of digester capacity, the evaluation should occur after both projects P1‐100 and P1‐101 are completed and sufficient performance data is available to accurately predict the characteristics of the digester feed sludge. If the evaluation determines that additional digester capacity is needed, a CIP project should be added in the future for Plant No. 1.

3.2.4 Sludge Diversion to Plant No. 2 Evaluation OCSD currently diverts sludge from Plant No. 1 to Plant No. 2 via the wastewater interplant line in order to accommodate construction and digester cleaning activities. Project P1‐101A built a

Final ‐ May 9, 2017 3‐6 Biosolids Master Plan Orange County Sanitation District | TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities temporary high‐density poly ethylene (HDPE) sludge line to route primary sludge to the 78‐inch interplant line through a connection to an existing filtrate line at the Metering and Diversion Structure. Project P1‐101 installed a more permanent connection and piping system, which provides the same function. The interplant line discharges to the Plant No. 2 headworks. This arrangement reduces the capacity in the interplant line and requires the primary sludge to be re‐ settled at Plant No. 2.

OCSD would like to evaluate the potential for adding a dedicated pipeline for primary sludge diversion from Plant No. 1 to Plant No. 2 that avoids using the interplant line and discharges the sludge upstream of the sludge blending tanks at Plant No. 2 (to avoid re‐settling). The two potential corridors for the new sludge diversion pipe are the Santa Ana River bike path and Brookhurst Street. Both options have unique sets of challenges and would require a new, dedicated pump station at Plant No. 1.

During the P1‐101 project, OCSD evaluated two optional diversion arrangements, but ultimately deemed them to be non‐viable. The first option was to insert a new sludge diversion line inside the existing and unused 66” interplant line. This option is no longer viable because the 66” interplant line is planned for use to convey Plant No. 2 secondary effluent to the Groundwater Replenishment System (GWRS) treatment plant adjacent to Plant No. 1. The second option was to use the interplant gas line, which was previously out of service. This option is no longer viable because the interplant gas line has been rehabilitated and is now in use.

It is recommended that OCSD evaluate the feasibility of installing a dedicated primary sludge pipeline to Plant No. 2 and the costs associated with this alternative.

3.2.5 Existing Drying Bed Modifications Evaluation The existing sludge drying beds at Plant No. 1 are located south of the primary clarifiers and west of the Secondary Clarifier No. 2 as show in Figure 3‐3.

SECONDARY CLARIFIER 2

N SLUDGE DRYING BEDS

Figure 3‐3. Plant No. 1 Sludge Drying Beds Location

Final ‐ May 9, 2017 3‐7 Biosolids Master Plan TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities | Orange County Sanitation District

The beds were originally designed for sludge drying, but are now predominantly used for grit. OCSD staff have identified two issues with the drying beds: 1) The current V‐shape of the beds (slope down to middle) requires grit dumpers to stand downhill of their trucks when dumping, resulting in wet grit running over their feet (see Figure 3‐4); and 2) The beds drain to a grated trench in the middle and the drain is easily clogged with grit and sawdust (see Figure 3‐5).

Figure 3‐4. Sludge Drying Bed Sloped Floors

Because the beds are being used for both sludge drying and grit dumping, OCSD staff would like to modify the bed arrangement to accommodate both uses.

It is recommended that OCSD evaluate the aforementioned issues with the sludge drying beds and develop recommended modifications or a new design to address those issues. It appears likely that the existing beds will need to be relocated in the future in order to expand more critical process facilities. At that time, the existing beds would be demolished and a new design could be constructed at a new location. If the evaluation recommends modification or relocation of the drying beds, a new Plant No. 1 CIP project should be added in the future. Figure 3‐5. Sludge Drying Bed Clogged Trench Drain

3.3 O&M IDENTIFIED ISSUES AND SOLUTIONS During discussions with OCSD plant staff, the following O&M issues were discussed, but are not included in the BMP CIP project list for the reasons noted.

Final ‐ May 9, 2017 3‐8 Biosolids Master Plan Orange County Sanitation District | TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities

3.3.1 Digester Roof Coating Repair The exterior digesters’ roof coatings were identified for repair by OCSD staff. The design will be done under the P1‐100 project and the construction work will be done under the J‐126 project and managed by the P1‐100 team.

3.3.2 Obsolete Boiler Demolition The boiler near Digesters 5 and 6 has been identified for demolition by OCSD plant staff. The project is currently going through the OCSD clearinghouse process and will not be included in the BMP CIP.

3.3.3 Provide Backup Water Sources for Digester Gas Compressor OCSD plant staff would like a backup water cooling water source for the digester gas compressors. This work will be included in J‐124.

3.3.4 Assess Condition of and Repair Piping from Ferric Pumps to Digesters OCSD plant staff noted that the piping from the ferric pumps to the digesters should be inspected and is in need of replacement. This work will be included in the P1‐105 project.

3.3.5 Repair Deficiencies Identified During P1‐100 Work During work on P1‐100 (Digester Rehabilitation at Plant No. 1), several items were identified for future repair after completion of the project. OSCD has noted these items will be handled as facilities engineering/repair (FE/FR) projects.

3.3.6 Repair WEMCO Mixing Pumps OCSD plant staff noted the WEMCO mixing pumps are experiencing excessive vibration. OCSD has repaired some of the pumps by using sheaves. The remaining pumps are scheduled to be repaired by OSCD maintenance staff.

3.3.7 Existing Hot Water Loop Evaluation The hot water recirculation loop is a critical element of the overall sludge heating system that maintains the desired temperature in the anaerobic digesters and is critical to their performance. The piping runs between the heat exchangers, boilers, and digesters and is located primarily in tunnels. OCSD recently hired a contractor to replace the old bellows‐type expansion joints with new metal‐cylinder type expansion joints (Flexicraft Model EP). As shown in Figure 3‐6, the expansion joints appear to have experienced considerable movement. Figure 3‐6. Example Hot Water Loop Expansion Joint

Final ‐ May 9, 2017 3‐9 Biosolids Master Plan TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities | Orange County Sanitation District

Per the manufacturer’s product information, this joint has an allowable axial extension of 0.75 inches. As shown in Figure 3‐6, the joint appears to be extended beyond the allowable 0.75 inches. Possible reasons for the axial extension include incorrect installation and/or incorrect pipe anchorage, which allowed the piping to extend beyond the manufacturer’s allowance.

In addition, OCSD operations staff has noted movement in the piping system at bends. As shown in Figure 3‐7, the upper piping appears to have expanded to the left as evidenced by the vertical piping being slightly rotated from the vertical position. A properly designed piping system with adequate anchorage will handle axial compression and expansion while preventing excessive pipe movement at the expansion joints.

Lastly, OCSD staff noted several areas where the piping insulation has been damaged (see Figure 3‐8).

Inadequate insulation Figure 3‐7. Hot Water Loop results in excess heat loss Piping Movement and an increase in energy usage to maintain temperatures in the hot water loop.

OCSD project FE15‐09 will evaluate the hot water loop piping system and make the recommended Figure 3‐8. Hot Water Loop Piping Insulation improvements, including replacement of the piping. Damage

Final ‐ May 9, 2017 3‐10 Biosolids Master Plan Orange County Sanitation District | TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities

4.0 Implementation Schedule and Sequencing The evaluations identified in Section 3.2 may be implemented based on priority and any predecessor activities. The evaluations with the highest priority that can be started immediately will take precedence. A summary of the evaluations and their sequencing criteria is provided in Table 4‐1.

Table 4‐1. Implementation Schedule and Sequencing EARLY EVALUATION PREDECESSOR ACTIVITIES PRIORITY START Digester Solids None Immediately High Screening Completion of P1‐100 and P1‐101 Digester Capacity JAN 2020 High projects and 1 year of operational data Sludge Diversion to None Immediately Medium Plant No. 2 Existing Drying Bed Identifying a project that would require Unknown Low Modifications removal of existing drying beds

The information in Table 4‐1 can be used to plan the future CIP evaluations.

Final ‐ May 9, 2017 4‐1 Biosolids Master Plan Orange County Sanitation District | TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities

5.0 Conclusions and Next Steps The potential for adding post‐dewatering facilities at Plant No. 1 was evaluated in Section 2.0. The base case alternative was no post‐dewatering facilities and the analysis looked at whether there may be economic incentives and non‐economic drivers for adding post‐dewatering facilities. Two post‐dewatering alternatives were initially identified: (1) partial drying with paddle dryings; and (2) thermal drying using rotary drum dryers. Partial drying was initially screened out based on non‐economic criteria. Thermal drying (with rotary drum technology) was then compared with no drying on an economic basis. Thermal drying had a higher NPV than the no drying option. In addition, OCSD staff noted several non‐economic concerns with thermal drying such as increased maintenance, equipment complexity, safety, and site constraints.

An evaluation of cake storage capacity in the existing silos was performed in Section 3.0. The results showed that there is sufficient capacity in the silos through 2035 over the expected range of dewatered cake solids concentrations.

A list of potential Plant No. 1 solids handling facilities evaluations was identified and developed in discussions with OCSD staff. It is recommended that the following four evaluations be performed to determine if future Plant No. 1 CIP projects are warranted.

 Digester Solids Screening Evaluation  Digester Capacity Evaluation  Sludge Diversion to Plant No. 2 Evaluation  Existing Drying Bed Modifications Evaluation

Final ‐ May 9, 2017 5‐1 Biosolids Master Plan Orange County Sanitation District | TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities

Appendix A – Process Design Calculation

Final ‐ May 9, 2017 A‐1 Biosolids Master Plan Excel Calculation Record Cover Sheet

Client Name: Orange County Sanitation District Page: of Project Name: Biosolids Master Plan Project No. 190875 176447 Calculation Title: Mass Balance - P1 Drying Component Calculation No./File No.:

Verification Method: x Check and Review Alternate Calculations

Objective: Develop conceptual sizing criteria, including mass and anergy balances for thermal drying options at Plant 1

Unverified Assumptions Requiring Subsequent Verification No. Assumption Verified By Date

For additional assumptions, refer to Page:

This Section Used for B&V Standard Computer-Aided Calculations Program Name/Number: Version: B&VIf yes, Standard Verfication Computer-Aided only requires checkingCalculation the Used? accuracy of inputs and reviewing reasonableness of outputs. Yes x No If no, Verification requires (1) checking of the actual formulas used in the calculation along with the accuracy of inputs, (2) Alternate Calculations created by the Verifier and reviewed by the Preparer, or (3) an approved deviation permit outlining Verification method

Review and Approval Rev Prepared By Date Verified By Date Approved By Date 1 Anjana Kadava 11/14/2016 Scott Carr 11/18/2016

Version 3.0 Cells with user input data

Abbreviations: AAD - annual average day MMAD - maximum month average day

Solids Productions: \\BCIRVFP01\Projects\_Projects\148814 - PS15-01 Plant 2 OCSD solids loading projections white paper

Solids Loading 2035 AA Primary 2035 AA Sec 2035 AA Sec 2035 AA Total 2035 15-day 2035 15-day Sec 2035 15-day Sec 2035 15-day 2035 15-day Total 2035 Max Day 2035 Max Day Sec 2035 Max Day Sec 2035 Max Day 2035 Max Day Total 2035 AA WAS + TF Sludge Sludge Sludge TF/SC Sludge Primary Sludge Sludge Sludge TF/SC WAS+TF Sludge Primary Sludge Sludge Sludge TF/SC WAS+TF Sludge Total pounds/ day 299,000 100,000 15,000 115,000 414,000 359,000 120,000 18,000 138,000 497,000 479,000 160,000 24,000 184,000 663,000 Percent total (%): 0.80 0.32 0.35 0.32 0.57 0.80 0.32 0.35 0.32 0.57 0.80 0.32 0.35 0.32 0.57 VS (%) 74 85 80 84.3 76.9 74 85 80 84.3 76.9 74 85 80 84.3 76.9 Flow (mgd) 4.48 3.75 0.51 4.26 8.74 5.38 4.50 0.62 5.11 10.49 7.18 6.00 0.82 6.82 14.00

Solids quantities based on Table 17. TS and VS based on mass balances in the attachement. Plant 2 condition 3.

2035 Max Day Solids Production Primary Sludge WAS Trickling Filter Sludge Total Sludge Total pounds/ day 479,000 160,000 24,000 663,000 Percent total (%): 0.80 0.32 0.35 0.58 VS (%) 74.0 85.0 80.0 76.5 Flow (mgd) 7.0 4.2 2.0 13.2

4.5% TS if continue to thicken in primary clairifier. Thickening Separate Combined Unit Thickending Thickening Thickened Sludge TS Thickened PS % Thickend WAS+TF % Thickened Combined % 4.7 6.0 Solids Capture Rate % 98 98

Digestion Unit Low High Volatile Solids Reduction Rate % 50 60 Biogas Production Rate scf/lb VSr 15 15

Specific Density PS 1.00 WAS 1.00 TF WS 1.00 Thickened Sludge 1.00 Digested Sludge 1.00 Average Annual Max-15 Day Max-Day Primary Sludge Use this to size primary sludge pumping, piping, and thickening) Primary Sludge TS ppd 299,000 359,000 479,000 Primary Sludge TS % 0.80 0.80 0.80 Primary Sludge VS ppd 221,260 265,660 354,460 Primary Sludge VS % of TS 74.0 74.0 74.0 Primary Sludge Flow gpd 4,481,415 5,380,695 7,179,257 WAS (Use this to size WAS pumping, piping, and thickening) WAS TS ppd 100,000 120,000 160,000 WAS TS % 0.32 0.32 0.32 WAS VS ppd 85,000 102,000 136,000 WAS VS % of TS 85.00 85.00 85.00 WAS Flow gpd 3,747,002 4,496,403 5,995,204 TF WS (Use this to size TF WS pumping, piping, and thickening) TF WS TS ppd 15,000 18,000 24,000 TF WS TS % 0.35 0.35 0.35 TF WS VS ppd 12,000 14,400 19,200 TF WS VS % of TS 80.00 80.00 80.00 TF WS Flow gpd 513,875 616,650 822,199

Total Sludge Total Sludge TS ppd 414,000 497,000 663,000 Total Sludge TS % 0.57 0.57 0.57 Total Sludge VS ppd 318,260 382,060 509,660 Total Sludge VS % of TS 76.87 76.87 76.87 Total Sludge Flow gpd 8,742,292 10,493,748 13,996,660

Thickened Sludge - Separate Thickening (Use this to size thickened sludge pumping, piping, storage, and digesters for separate thickening alternative) Thickened Sludge TS ppd 405,720 487,060 649,740 Thickened Sludge TS % 4.70 4.70 4.70 Thickened Sludge VS ppd 311,895 374,419 499,467 Thickened Sludge VS % of TS 76.87 76.87 76.87 Thickened Sludge Flow gpd 1,035,053 1,242,563 1,657,585

Digested Sludge - Low VSR (Use this for dewatering equipment sizing and beneficial digester gas use evaluation etc.) VSR 50% VSR ppd 155,947 187,209 249,733 Digested Sludge TS ppd 249,773 299,851 400,007 Digested Sludge TS % 2.89 2.89 2.89 Digested Sludge VS ppd 155,947 187,209 249,733 Digested Sludge VS % of TS 62.44 62.43 62.43 Digested Sludge Flow gpd 1,035,053 1,242,563 1,657,585 Digester Gas Production scf/day 2,339,211 2,808,141 3,746,001

Digested Sludge - High VSR (Use this for digester gas handling equipment and pipe, digester emergency overflow pipe sizing etc.) VSR 60% VSR ppd 187,137 224,651 299,680 Digested Sludge TS ppd 218,583 262,409 350,060 Digested Sludge TS % 2.53 2.53 2.53 Digested Sludge VS ppd 124,758 149,768 199,787 Digested Sludge VS % of TS 57.08 57.07 57.07 Digested Sludge Flow gpd 1,035,053 1,242,563 1,657,585 Digester Gas Production scf/day 2,807,053 3,369,769 4,495,201 Calculation of Ultimate Solids Production Cells with user input data Reference green box for initial data on "Solids Load" tab

Primary Solids Average annual, ppd 443,000 From Table 4-2, TM1 (see green box on tab "Solids Load") 15-day max, ppd 532,000 From Table 4-2, TM1 (see green box on tab "Solids Load") VS, % of TS 74 From "Separate Thickening" tab Average Annual VS, ppd 327,820 15-day max VS, ppd 393,680

WAS Average annual, ppd 174,000 From Table 4-2, TM1 (see green box on tab "Solids Load") 15-day max, ppd 209,000 From Table 4-2, TM1 (see green box on tab "Solids Load") VS, % of TS 85.00 From "Separate Thickening" tab Average Annual VS, ppd 147,900 15-day max VS, ppd 177,650

TF Sludge Average annual, ppd 12,000 From Table 4-2, TM1 (see green box on tab "Solids Load") 15-day max, ppd 15,000 From Table 4-2, TM1 (see green box on tab "Solids Load") VS, % of TS 80.00 From "Separate Thickening" tab Average Annual VS, ppd 9,600 15-day max VS, ppd 12,000

Feed to Digestion Average annual, ppd 629,000 15-day max, ppd 756,000 Average Annual VS, ppd 485,320 15-day max VS, ppd 583,330 Composite VS, % of TS 77

Digested Solids VSR, % 60 Used high VSR values from "Assumptions" tab VS destroyed, ppd Average annual, ppd 291,192 15-day max, ppd 349,998 Digested solids, ppd Average annual, ppd 337,808 169 dtpd 15-day max, ppd 406,002 203 dtpd Rotary Drum Dryer Sizing Calculations - OCSD Plant 1 Cells with user input data 2035 Design Conditions

Input Parameters Solids Feed Information Average annual digested solids production, dtpd 109 Data from "Separate Thickening" tab Dryer Operating hours 15-day max digested solids production, dtpd 131 Data from "Separate Thickening" tab Start Stop Hrs/wk 25% used based on experience at operating facilities Dewatered solids concentration, % TS 25 for optimal performance of drying Monday 8 a.m. Friday 5 p.m. 105 Final product solids concentration, % TS 92 Monday 8 a.m. Friday Noon 100 Dryer Operation Monday 8 a.m. Fiday 8 a.m. 96 Average annual conditions, hrs/week 168 Refer to Operating Hours (blue box) Monday 8 a.m. Thursday 5 p.m. 81 15-day max conditions, hrs/week 168 Refer to Operating Hours (blue box) Monday 8 a.m. Saturday 8 a.m. 120 Weeks per year 52 Continuous Operation 168 Manipulate to correspond with suitable dryer sizes provided by manfactuers. Used value of 1 to calculate the total evaporative load required, and then used "Dryer Selection" tab for identifying best Number of dryer units required 1 options for number of units Economic and Energy Parameters Electric power costs, $/kWh 0.055 Heat energy requirement, BTU/lb H2O evaporated 1500 Excludes energy for odor control with RTO. Heat energy requirement for RTO for odor control, Indicate Yes or No if BTU/lbH2O evaporated 100 RTO is used yes Biogas quantity available, cf/day 0 Biogas heat value, BTU/cf 600 Natural gas cost, $/MMBTU 6.00

Average Calculations Annual 15-day Max Dryer Feed Characteristics (per unit) dt/hr/unit 4.6 5.5 wt/hr/unit 18.2 21.9 Product Characteristics dt/hr/unit 4.6 5.5 wt/hr/unit 4.9 5.9 Dryer evaporation rate, lb H2O/hr/unit lb H2O/hr/unit 26,531 31,850 Identify controlling condition(conditional statement used). kg H2O/hr/unit 12,038 14,451 15-Day Max

Heat energy required for drying*, MMBTU/yr 347,661 Heat energy required for odor control*, MMBTU/yr 23,177 Heat energy provided by biogas, MMBTU/yr 0 Natural gas to be purchased, MMBTU/yr 370,839 Rotary Drum Dryer Sizing Calculations - OCSD Plant 1 Cells with user input data Ultimate Design Conditions

Input Parameters Solids Feed Information Average annual digested solids production, dtpd 169 Reference calculations on "Ultimate Solids" tab Dryer Operating hours 15-day max digested solids production, dtpd 203 Reference calculations on "Ultimate Solids" tab Start Stop Hrs/wk 25% used based on experience at operating facilities Dewatered solids concentration, % TS 25 for optimal performance of drying Monday 8 a.m. Friday 5 p.m. 105 Final product solids concentration, % TS 92 Monday 8 a.m. Friday Noon 100 Dryer Operation Monday 8 a.m. Fiday 8 a.m. 96 Average annual conditions, hrs/week 168 Refer to Operating Hours (blue box) Monday 8 a.m. Thursday 5 p.m. 81 15-day max conditions, hrs/week 168 Refer to Operating Hours (blue box) Monday 8 a.m. Saturday 8 a.m. 120 Weeks per year 52 Continuous Operation 168 Manipulate to correspond with suitable dryer sizes provided by manfactuers. Used value of 1 to calculate the total evaporative load required, and then used "Dryer Selection" tab for identifying best Number of dryer units required 1 options for number of units Economic and Energy Parameters Electric power costs, $/kWh 0.055 Heat energy requirement, BTU/lb H2O evaporated 1500 Excludes energy for odor control with RTO. Heat energy requirement for RTO for odor control, Indicate Yes or No if BTU/lbH2O evaporated 100 RTO is used yes Biogas quantity available, cf/day 0 Biogas heat value, BTU/cf 600 Natural gas cost, $/MMBTU 6.00

Average Calculations Annual 15-day Max Dryer Feed Characteristics (per unit) dt/hr/unit 7.0 8.5 wt/hr/unit 28.2 33.8 Product Characteristics dt/hr/unit 7.0 8.5 wt/hr/unit 7.6 9.2 Dryer evaporation rate, lb H2O/hr/unit lb H2O/hr/unit 41,002 49,279 Identify controlling condition(conditional statement used). kg H2O/hr/unit 18,603 22,359 15-Day Max

Heat energy required for drying*, MMBTU/yr 537,291 Heat energy required for odor control*, MMBTU/yr 35,819 Heat energy provided by biogas, MMBTU/yr 0 Natural gas to be purchased, MMBTU/yr 573,110 Thermal Dryer Sizing Calculations - OCSD Plant 1 Cells with user input data Rotary Drum Dryer

Current Solids Loading (2014): estimated using 55% VSR Average annual digested, ppd 234,178 15-day max month digested, ppd 281,130 Average evap rate, kg H2O/hr 12,896 15-day max evap rate, kg H2O/hr 15,482

Use Andritz sizing as the Basis Evaporative Andritz Model Capacity, kg H2O/hr DDS70 7,000 DDS80 8,000 DDS90 9,000 DDS100 10,000

Dryer Evaporation Capacity Requirements Annual average, 15-day max, kg Design Condition kg H2O/hr H2O/hr Future (2035) 12,038 14,451 Ultimate 18,603 22,359

Units Operating (Rounded up to next operational unit)

at annual average conditions average unit load, average unit % of design at 15-day max conditions load, % of design Not rounded Rounded up Not rounded Rounded up DDS70 Current 1.84 2 92 2.21 3 74 Future (2035) 1.72 2 86 2.06 3 69 Ultimate 2.66 3 89 3.19 4 80 DDS80 Current 1.61 2 81 1.94 2 97 Future (2035) 1.50 2 75 1.81 2 90 Ultimate 2.33 3 78 2.79 3 93 DDS90 Current 1.43 2 72 1.72 2 86 Future (2035) 1.34 2 67 1.61 2 80 Ultimate 2.07 3 69 2.48 3 83 DDS100 Current 1.29 2 64 1.55 2 77 Future (2035) 1.20 2 60 1.45 2 72 Ultimate 1.86 2 93 2.24 3 75 7 Days/Week - 24 Hours/Day Operation (New Facilities) REGENERATIVE THERMAL 7 Days/Week - 24 Hours/Day Operation OXIDIZER CONDENSER FEED (Existing Facilities) WATER 6 CONDENSER

4 7 8 CONDENSATE MIXER DIRECT DRYER NATURAL GAS TO RTO

CAKE SILO RECYCLE STORAGE

5 BURNER PRODUCT SCREENING NATURAL GAS PRODUCT COOLING ANAEROBIC SLUDGE DIGESTION 1 HOLDING

Pneumatic Transporter 9

2 CENTRIFUGE DEWATERING WET CAKE RECEIVING BIN PRODUCT SILO

3

BACKUP DEWATERED CAKE LOAD OUT TRUCK LOAD OUT

ENTER DATA IN CELLS CAPTURE

Parameter Units 7 d/wk 7 d/wk INPUT DATA 1 2 3 4 5 6 7 8 9 Stream Digested Cent. Feed Centrate Cake Burner Condenser Feed Water Condensate RTO Product ANNUAL Digested dtpd 109 Solids Quantity dt/hr 4.6 4.6 0.0 4.6 ------4.6 Overall Process Schematic, Solids & Energy Balance AVERAGE % TS - Digested % 2.9 dry lbs/hr 9,200 9,200 0 9,200 ------9,200 % Capture - Centrifuge % 100 % TS 2.9 2.9 0.0 25.0 ------92 % TS - Dewatered Cake % 25 wt/hr 157 157 0 18 ------4.9 % TS - Dried Product % 92 Flow gpm 640 640 566 -- -- 1,700 1,750 -- -- Condenser Feed Water Total gpm 1700 Energy MMBTU/hr ------39.8 -- -- 2.7 -- Operation time hr / wk 168

Parameter Units 7 d/wk 7 d/wk ALTERNATIVE 1: ROTARY DRUM TECHNOLOGY INPUT DATA 1 2 3 4 5 6 7 8 9 Stream Digested Cent. Feed Centrate Cake Burner Condenser Feed Water Condensate RTO Product 15 DAY Digested dtpd 131 Solids Quantity dt/hr 5.5 5.5 0.0 5.5 ------5.5 MAXIMUM % TS - Digested % 2.9 dry lbs/hr 11,000 11,000 0 11,000 ------11,000 % Capture - Centrifuge % 100 % TS 2.9 2.9 0.0 25.0 ------92 % TS - Dewatered Cake % 25 wt/hr 189 189 0 22 ------5.9 % TS - Dried Product % 92 Flow gpm 760 760 672 -- -- 1,700 1,760 -- -- Condenser Feed Water Total gpm 1700 Energy MMBTU/hr ------47.8 -- -- 3.2 -- Operation time hr / wk 168

ENERGY Dryer (BTU / lb H2O Evaporated) 1500 CONTENT RTO (BTU / lb H2O Evaporated) 100 OCSD Biosolids Master Plan TM 7 ‐ CIP Project Development for Plant No. 1 Solids Handling Facilities Plant No. 1 Cake Silo Storage Capacity Evaluation Calculations

Table 1. Cake Silo Performance and Operation Assumptions: CRITERIAVALUE SOURCE Design Year 2035 OCSD White Paper, Condition 1 Design Flow 125 mgd OCSD White Paper, Condition 1 Digested Sludge TSS 216,593 lb/d OCSD White Paper, Condition 1 Solids Capture Rate (Dewatering Centrifuge) 97% OCSD White Paper, Condition 1 Dewatered Cake 210,095 lb/d Calculation Dewatered Cake Specific Weight 64 lb/cf OCSD White Paper, Condition 1 Usable Cake Silo Volume (ea.) 12,100 cf P1‐101 Evaluation and Drawing Calculations Number of Cake Silos 4 Truck Volume 30 cy P1‐101 Evaluation Truck Loading Time 15 min P1‐101 Evaluation No. of Trucks Loading at a Time 1 Loading Hours 8 hrs/day P1‐101 Evaluation 3.5 days Storage Duration Required P1‐101 Evaluation 5,040 min

1 of 4 OCSD Biosolids Master Plan TM 7 ‐ CIP Project Development for Plant No. 1 Solids Handling Facilities Plant No. 1 Cake Silo Storage Capacity Evaluation Calculations

Table 2. Cake Silo Storage Duration Calculations DEWATERED CAKE THICKNESS 25% 26% 27% 28% 29% 30% 23.74% Total Cake Silo Storage Volume (cf) 48,400 48,400 48,400 48,400 48,400 48,400 48,400 Wet Cake (lb/d) 840,381 808,059 778,130 750,340 724,466 700,317 885,029 Wet Cake (tons/d) 420 404 389 375 362 350 443 Wet Cake (cf/d) 13,131 12,626 12,158 11,724 11,320 10,942 13,829 Wet Cake (cf/min) 9.1 8.8 8.4 8.1 7.9 7.6 9.6 Storage Duration (min) 5,308 5,520 5,732 5,945 6,157 6,369 5,040 Storage Duration (days) 3.69 3.83 3.98 4.13 4.28 4.42 3.50

2 of 4 OCSD Biosolids Master Plan TM 7 ‐ CIP Project Development for Plant No. 1 Solids Handling Facilities Plant No. 1 Cake Silo Storage Capacity Evaluation Calculations

Figure 1. Cake Silo Volume Calculations with Silo Full Top Radius 15 ft Top EL 56.67 Mid‐EL 42.49 Bottom EL 27.99 R =15ft Bottom R 6 ft EL 56.67

Volume 1 R = 15.00 ft H = 14.18 ft V = 10,021 cf Volume 1 = 10,021 cf

Volume 2 R2 15 ft R1 6 ft EL 42.49 H 14.5 ft V 5,330 cf 14.5 Volume 2 = 5,330 cf

EL 27.99

R =6ft

Volume = 15,351 cf

3 of 4 OCSD Biosolids Master Plan TM 7 ‐ CIP Project Development for Plant No. 1 Solids Handling Facilities Plant No. 1 Cake Silo Storage Capacity Evaluation Calculations

Figure 2. Cake Silo Level Calculations for 12,100 CF Volume Top Radius 15 ft Top EL 52.07 Mid‐EL 42.49 R =15ft Bottom EL 27.99 Bottom R 6 ft EL 56.67 PRV 55.5 Volume 1Max Cake EL 52.07 R = 15.00 ft 4.60 H = 9.58 ft 3.43 V = 6,770 cf Volume 1 = 6,770 cf

Volume 2 R2 15 ft R1 6 ft EL 42.49 H 14.5 ft V 5,330 cf 14.5 Volume 2 = 5,330 cf

EL 27.99

R =6ft

Volume = 12,100 cf

4 of 4 Orange County Sanitation District | TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities

Appendix B – SWEET Cost Model Data

Final ‐ May 9, 2017 B‐1 Biosolids Master Plan Risk adjustments (+/- percent): Year of analysis 2023 Benefits Alternative 1: Plant No.1 without drying Escalation rate 3.50% Capital costs Life Cycle Alternative Cost Analysis ($000s) Discount rate 4.00% Running costs

Year 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 Expressed in 2023 dollars, unescalated -- dollars

Capital Outlays Capital Capital Outlay 2 Capital Outlay 3 Capital Outlay 4 Capital Outlay 5 Capital Outlay 6 Capital Outlay 7 Capital Outlay 8 Total capital outlays

Benefits: Benefit 1 Benefit 2 Benefit 3 Total benefits

Annual Running Costs: Polymers, $/y Class B Cake Land App, $/y 2,757,060 2,771,500 2,785,941 2,800,381 2,814,822 2,829,262 2,843,703 2,858,143 2,872,583 2,887,024 2,901,464 2,915,905 2,930,345 2,944,786 2,959,226 2,973,667 2,988,107 3,002,547 3,016,988 3,031,428 3,045,869 Compost to Class A, $/y 2,807,188 2,821,891 2,836,594 2,851,297 2,866,000 2,880,703 2,895,406 2,910,109 2,924,812 2,939,515 2,954,218 2,968,921 2,983,624 2,998,327 3,013,030 3,027,733 3,042,436 3,057,139 3,071,842 3,086,545 3,101,248 Running cost 4 Running cost 5 Running cost 6 Running cost 7 Running cost 8 Running cost 9 Running cost 10 Running cost 11 Running cost 12 Total running costs 5,564,248 5,593,392 5,622,535 5,651,678 5,680,822 5,709,965 5,739,109 5,768,252 5,797,396 5,826,539 5,855,683 5,884,826 5,913,969 5,943,113 5,972,256 6,001,400 6,030,543 6,059,687 6,088,830 6,117,974 6,147,117

Contract Maintenance Cost Maintenance 1 Maintenance 2 Maintenance 3 Maintenance 4 Maintenance 5 Maintenance 6 Total risk costs

R&R Costs: R&R Cost 1 R&R Cost 2 R&R Cost 3 R&R Cost 4 R&R Cost 5 R&R Cost 6 R&R Cost 7 R&R Cost 8 Total refurbishments

Net Benefit/(cost) (5,564,248) (5,593,392) (5,622,535) (5,651,678) (5,680,822) (5,709,965) (5,739,109) (5,768,252) (5,797,396) (5,826,539) (5,855,683) (5,884,826) (5,913,969) (5,943,113) (5,972,256) (6,001,400) (6,030,543) (6,059,687) (6,088,830) (6,117,974) (6,147,117)

Expressed in escalated dollars with sensitivity adjustments

Capital Outlays Capital Capital Outlay 2 Capital Outlay 3 Capital Outlay 4 Capital Outlay 5 Capital Outlay 6 Capital Outlay 7 Capital Outlay 8 Total capital outlays

Benefits: Benefit 1 Benefit 2 Benefit 3 Total benefits

Annual Running Costs: Polymers, $/y Class B Cake Land App, $/y 2,757,060 2,868,503 2,984,369 3,104,833 3,230,073 3,360,276 3,495,636 3,636,356 3,782,644 3,934,717 4,092,802 4,257,133 4,427,953 4,605,515 4,790,083 4,981,929 5,181,336 5,388,598 5,604,022 5,827,925 6,060,636 Compost to Class A, $/y 2,807,188 2,920,657 3,038,631 3,161,284 3,288,801 3,421,372 3,559,194 3,702,472 3,851,419 4,006,258 4,167,217 4,334,535 4,508,461 4,689,252 4,877,176 5,072,509 5,275,542 5,486,573 5,705,914 5,933,887 6,170,829 Running cost 4 Running cost 5 Running cost 6 Running cost 7 Running cost 8 Running cost 9 Running cost 10 Running cost 11 Running cost 12 Total running costs 5,564,248 5,789,160 6,023,000 6,266,117 6,518,874 6,781,648 7,054,830 7,338,828 7,634,063 7,940,975 8,260,019 8,591,668 8,936,414 9,294,767 9,667,259 10,054,438 10,456,878 10,875,171 11,309,936 11,761,812 12,231,465

Contract Maintenance Cost Maintenance 1 Maintenance 2 Maintenance 3 Maintenance 4 Maintenance 5 Maintenance 6 Total risk costs

R&R Costs: R&R Cost 1 R&R Cost 2 R&R Cost 3 R&R Cost 4 R&R Cost 5 R&R Cost 6 R&R Cost 7 R&R Cost 8 Total refurbishments

Net escalated benefit/(cost) (5,564,248) (5,789,160) (6,023,000) (6,266,117) (6,518,874) (6,781,648) (7,054,830) (7,338,828) (7,634,063) (7,940,975) (8,260,019) (8,591,668) (8,936,414) (9,294,767) (9,667,259) (10,054,438) (10,456,878) (10,875,171) (11,309,936) (11,761,812) (12,231,465)

Life cycle cost analysis

PVs in 2023 (5,564,248) (5,566,500) (5,568,602) (5,570,555) (5,572,361) (5,574,020) (5,575,535) (5,576,906) (5,578,135) (5,579,223) (5,580,173) (5,580,984) (5,581,658) (5,582,196) (5,582,601) (5,582,873) (5,583,013) (5,583,022) (5,582,903) (5,582,655) (5,582,281)

NPV as of 2023 (117,130,442)

Appendix A, Page 1 of 1 Alt_1 Risk adjustments (+/- percent): Year of analysis 2023 Benefits Alternative 2: Plant No.1 with drying Escalation rate 3.50% Capital costs Life Cycle Alternative Cost Analysis ($000s) Discount rate 4.00% Running costs

Year 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 Expressed in 2023 dollars, unescalated -- dollars

Capital Outlays Capital 52,741,000 Capital Outlay 2 Capital Outlay 3 Capital Outlay 4 Capital Outlay 5 Capital Outlay 6 Capital Outlay 7 Capital Outlay 8 Total capital outlays 52,741,000

Benefits: Benefit 1 Benefit 2 Benefit 3 Total benefits

Annual Running Costs: Natural gas used, $/y 1,220,681 1,227,075 1,233,468 1,239,861 1,246,255 1,252,648 1,259,042 1,265,435 1,271,829 1,278,222 1,284,616 1,291,009 1,297,403 1,303,796 1,310,190 1,316,583 1,322,977 1,329,370 1,335,764 1,342,157 1,348,550 Labor, $/y 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 1,007,635 Energy 833,864 838,231 842,599 846,966 851,334 855,701 860,069 864,436 868,804 873,171 877,538 881,906 886,273 890,641 895,008 899,376 903,743 908,111 912,478 916,846 921,213 Water Demand - Drying($/y) 38,597 38,799 39,001 39,203 39,405 39,607 39,810 40,012 40,214 40,416 40,618 40,820 41,023 41,225 41,427 41,629 41,831 42,033 42,235 42,438 42,640 Class A Dried Granule to Land App (CA) 54,923 55,211 55,499 55,786 56,074 56,362 56,649 56,937 57,225 57,512 57,800 58,088 58,375 58,663 58,951 59,238 59,526 59,814 60,101 60,389 60,677 Class A Dried Granule to Land App (AZ) 68,654 69,014 69,373 69,733 70,092 70,452 70,812 71,171 71,531 71,890 72,250 72,609 72,969 73,329 73,688 74,048 74,407 74,767 75,127 75,486 75,846 Class A Dried Granule to Bulk Horticulture 238000.7409 239,247 240,494 241,740 242,987 244,234 245,480 246,727 247,973 249,220 250,466 251,713 252,959 254,206 255,453 256,699 257,946 259,192 260,439 261,685 262,932 Class A Dried Granule to Fertilizer Blending 109846.4958 110,422 110,997 111,573 112,148 112,723 113,299 113,874 114,449 115,025 115,600 116,175 116,751 117,326 117,901 118,477 119,052 119,627 120,203 120,778 121,353 Running cost 9 Running cost 10 Running cost 11 Running cost 12 Total running costs 3,572,201 3,585,634 3,599,066 3,612,498 3,625,930 3,639,362 3,652,795 3,666,227 3,679,659 3,693,091 3,706,524 3,719,956 3,733,388 3,746,820 3,760,253 3,773,685 3,787,117 3,800,549 3,813,982 3,827,414 3,840,846

Contract Maintenance Cost Dryer Maintenance 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 Maintenance 2 Maintenance 3 Maintenance 4 Maintenance 5 Maintenance 6 Total risk costs 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000 879,000

R&R Costs: Equipment Replacement 3,602,000 R&R Cost 2 R&R Cost 3 R&R Cost 4 R&R Cost 5 R&R Cost 6 R&R Cost 7 R&R Cost 8 Total refurbishments 3,602,000

Net Benefit/(cost) (57,192,201) (4,464,634) (4,478,066) (4,491,498) (4,504,930) (4,518,362) (4,531,795) (4,545,227) (4,558,659) (4,572,091) (4,585,524) (4,598,956) (4,612,388) (4,625,820) (4,639,253) (4,652,685) (4,666,117) (4,679,549) (4,692,982) (4,706,414) (8,321,846)

Expressed in escalated dollars with sensitivity adjustments

Capital Outlays Capital Capital Outlay 2 Capital Outlay 3 Capital Outlay 4 Capital Outlay 5 Capital Outlay 6 Capital Outlay 7 Capital Outlay 8 Total capital outlays

Benefits: Benefit 1 Benefit 2 Benefit 3 Total benefits

Annual Running Costs: Natural gas used, $/y 1,220,681 1,270,022 1,321,322 1,374,657 1,430,106 1,487,753 1,547,684 1,609,987 1,674,756 1,742,086 1,812,077 1,884,834 1,960,465 2,039,080 2,120,797 2,205,736 2,294,023 2,385,788 2,481,166 2,580,299 2,683,331 Labor, $/y 1,007,635 1,042,902 1,079,404 1,117,183 1,156,285 1,196,755 1,238,641 1,281,993 1,326,863 1,373,303 1,421,369 1,471,117 1,522,606 1,575,897 1,631,054 1,688,140 1,747,225 1,808,378 1,871,671 1,937,180 2,004,981 Energy 833,864 867,569 902,613 939,047 976,925 1,016,304 1,057,244 1,099,804 1,144,048 1,190,042 1,237,855 1,287,556 1,339,220 1,392,923 1,448,745 1,506,768 1,567,078 1,629,764 1,694,918 1,762,637 1,833,020 Water Demand - Drying($/y) 38,597 40,157 41,779 43,465 45,218 47,041 48,936 50,906 52,954 55,083 57,296 59,597 61,988 64,474 67,057 69,743 72,535 75,436 78,452 81,586 84,844 Class A Dried Granule to Land App (CA) 54,923 57,143 59,451 61,851 64,346 66,940 69,636 72,440 75,354 78,383 81,532 84,806 88,209 91,746 95,423 99,245 103,217 107,346 111,637 116,098 120,734 Class A Dried Granule to Land App (AZ) 68,654 71,429 74,314 77,314 80,433 83,675 87,045 90,550 94,192 97,979 101,916 106,008 110,261 114,683 119,279 124,056 129,021 134,182 139,547 145,122 150,917 Class A Dried Granule to Bulk Horticulture 238,001 247,621 257,623 268,022 278,833 290,073 301,758 313,905 326,533 339,661 353,307 367,493 382,239 397,567 413,500 430,061 447,274 465,166 483,762 503,090 523,179 Class A Dried Granule to Fertilizer Blending 109,846 114,287 118,903 123,702 128,692 133,880 139,273 144,879 150,708 156,767 163,065 169,612 176,418 183,492 190,846 198,489 206,434 214,692 223,275 232,196 241,467 Running cost 9 Running cost 10 Running cost 11 Running cost 12 Total running costs 3,572,201 3,711,131 3,855,409 4,005,241 4,160,838 4,322,421 4,490,217 4,664,464 4,845,408 5,033,304 5,228,418 5,431,023 5,641,406 5,859,862 6,086,700 6,322,238 6,566,808 6,820,753 7,084,429 7,358,208 7,642,473

Contract Maintenance Cost Dryer Maintenance 879,000 909,765 941,607 974,563 1,008,673 1,043,976 1,080,515 1,118,333 1,157,475 1,197,987 1,239,916 1,283,313 1,328,229 1,374,717 1,422,832 1,472,632 1,524,174 1,577,520 1,632,733 1,689,879 1,749,024 Maintenance 2 Maintenance 3 Maintenance 4 Maintenance 5 Maintenance 6 Total risk costs 879,000 909,765 941,607 974,563 1,008,673 1,043,976 1,080,515 1,118,333 1,157,475 1,197,987 1,239,916 1,283,313 1,328,229 1,374,717 1,422,832 1,472,632 1,524,174 1,577,520 1,632,733 1,689,879 1,749,024

R&R Costs: Equipment Replacement 7,167,219 R&R Cost 2 R&R Cost 3 R&R Cost 4 R&R Cost 5 R&R Cost 6 R&R Cost 7 R&R Cost 8 Total refurbishments 7,167,219

Net escalated benefit/(cost) (4,451,201) (4,620,896) (4,797,016) (4,979,804) (5,169,511) (5,366,397) (5,570,733) (5,782,798) (6,002,884) (6,231,291) (6,468,334) (6,714,336) (6,969,635) (7,234,580) (7,509,533) (7,794,870) (8,090,982) (8,398,273) (8,717,162) (9,048,087) (16,558,716)

Life cycle cost analysis

PVs in 2023 (4,451,201) (4,443,169) (4,435,111) (4,427,028) (4,418,920) (4,410,787) (4,402,631) (4,394,451) (4,386,248) (4,378,023) (4,369,775) (4,361,505) (4,353,214) (4,344,901) (4,336,568) (4,328,215) (4,319,841) (4,311,448) (4,303,037) (4,294,606) (7,557,182)

NPV as of 2023 (95,027,860)

Appendix A, Page 1 of 1 Alt_2 Orange County Sanitation District | TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities

Appendix C – Task 7 Meeting Minutes

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

B&V Job 190875 PS15-01 No. OCSD BIOSOLIDS MASTER PLAN Date: January 3, 2016

FINAL MEETING MINUTES Page: 1 of 6

Meeting Location: Plant No. 1 Conference Room C Meeting Date: December 20, 2016 Meeting Time: 9:00 AM to 11:00 AM Meeting Topic: Task 7.2 – Plant No. 1 Post-Dewatering Evaluation and CIP Projects Revision Date: Authored By: Jake Holden and Dan Buhrmaster

Attendees: OCSD Team Black & Veatch/ Brown and Caldwell Team Sharon Yin Michelle Hetherington Jim Clark – Black & Veatch Jon Bradley Nasrin Nasrollahi Dan Buhrmaster – Black & Veatch Kathy Millea Tom Meregillano Matt Thomas – Black & Veatch Martin Dix Jake Holden – Black & Veatch Scott Carr – Black & Veatch (via phone)

Handouts: See attached

The key points that were discussed in the meeting are summarized below and follow the order of the meeting agenda. Some points may not be recorded in the same sequence as actually discussed. Action items are noted below and will be included in the Action Item Log.

No. Item Action By Due Date 1 MEETING PURPOSE  Present recommendation on post-dewatering facilities  Present cake storage evaluation  Present Plant No. 1 evaluation list for future projects 2 SAFETY MOMENT  B&V/BC provided a safety moment on holiday decorating. 3 POST – DEWATERING EVALUATION  B&V/BC reviewed post-dewatering product and market alternatives from Task 3.  Only new thermal drying and partial drying facilities were considered in accordance with the scope of work and because the Plant 1 digesters do not have the seismic issues that exist at Plant 2.  Partial drying was eliminated from further consideration at Plant 1 for the following reasons: (1) it received the lowest non-economic score during the Plant 2 evaluation, (2) partially dried solids can be difficult to handle and typically this alternative is accomplished with solar drying, and (3) the approach of using a paddle

The above represents the author’s understanding of the items discussed and the decisions made during the context of the meeting. All items are assumed to be correct if the author is not contacted with clarifications.

B&V Job 190875 PS15-01 No. OCSD BIOSOLIDS MASTER PLAN Date: January 3, 2016

FINAL MEETING MINUTES Page: 2 of 6

No. Item Action By Due Date dryer and blending with dewatered cake has not been fully proven at other plants.  B&V/BC reviewed thermal drying drivers, technologies, and manufacturers. Thermal drying was compared with a “no drying” alternative for this evaluation.  B&V/BC reviewed the concept design for the Plant No. 1 rotary drum (thermal) dryers.  B&V/BC reviewed the site layout and noted a potential location for the dryers based on future demolition projects. It was noted that the drying facility would occupy a large fraction of the site space that will open up after the demolition of existing facilities after P1-101 is complete. It is OCSD’s goal to keep open site space for future facilities whenever possible.  B&V/BC reviewed the SWEET NPV cost evaluation results, noting that thermal drying has an NPV $15-20M greater the no drying alternative. The O&M savings associated with thermal drying is a significant reduction in the volume of biosolids and truck hauling. However, this savings was not enough to offset the capital and O&M costs associated with new thermal drying.  B&V/BC recommended not to install thermal drying at Plant 1, and OCSD concurred, for the following general Decision reasons:  Higher NPV for thermal drying  Greater O&M complexity  Safety issues associated with high temperatures and dust concerns, while noting that these can be largely mitigated through proper O&M  Site space constraints

4 CAKE SILO STORAGE EVALUATION  B&V/BC performed an evaluation of the cake silo storage volume to confirm whether sufficient capacity is projected for the future. A minimum of 3.5 days of storage is needed to accommodate a hauling schedule of approximately 5 days per week.  B&V/BC evaluated the silo storage capacity over a range of 25-30% solids concentration. This range of solids concentration was used because the actual performance of the new dewatering centrifuges has not yet been established.

The above represents the author’s understanding of the items discussed and the decisions made during the context of the meeting. All items are assumed to be correct if the author is not contacted with clarifications.

B&V Job 190875 PS15-01 No. OCSD BIOSOLIDS MASTER PLAN Date: January 3, 2016

FINAL MEETING MINUTES Page: 3 of 6

No. Item Action By Due Date  The results of the evaluation show that that the cake silos have adequate storage capacity for 3.5 days of storage between 25-30% cake thickness, assuming all 4 silos are in operation.  OCSD requested the table on slide 28, which shows storage duration vs. dewatered cake thickness. B&V/BC Complete  It was noted there is additional volume in the truck loading hopper, downstream of the silos, that was not included in the evaluation.

5 PLANT NO. 1 RECOMMENDED BIOSOLIDS AND GAS TREATMENT EVALUATIONS  A meeting was held on November 30 between OCSD and B&V/BC with the purpose of identifying any new evaluations or projects that should be included in the Biosolids Master Plan (BMP). A site walk down was also conducted to assist in the discussion. The following five evaluations were recommended for inclusion in the BMP, the evaluations were discussed in detail, and OCSD Decision concurred: 1) Evaluate Solids Screening for Digesters o During the digester cleaning process, it is currently necessary to transfer digested sludge from the digester to be cleaned to operating digesters. As a result, unwanted grit and rags are transferred from the dirty digester to clean digesters. o The transfer of rags often causes clogging of the digester overflows. Operations staff has to then plunge the overflows on the clean digesters, to alleviate the blockage. o There are at least two potential solutions to minimize the transfer of rags and grit: 1) provide an in-line screen (Huber strain press) in the transfer loop to capture debris before it’s transferred to the clean digester; 2) provide screens upstream of the existing blending tanks to minimize rags prior to digestion. o It was noted that this type of screening may have O&M challenges associated with handling of screenings and odor control. However, plant staff would like to have a detailed evaluation this equipment, including seeing these screens in service. o In TM-7, B&V will include the solids screening as a

The above represents the author’s understanding of the items discussed and the decisions made during the context of the meeting. All items are assumed to be correct if the author is not contacted with clarifications.

B&V Job 190875 PS15-01 No. OCSD BIOSOLIDS MASTER PLAN Date: January 3, 2016

FINAL MEETING MINUTES Page: 4 of 6

No. Item Action By Due Date recommended evaluation and will note that a similar study could be considered for Plant No. 2 digested sludge screening. 2) Evaluate Existing Hot Water Loop o OCSD noted the recent bellows expansion joints were not installed correctly (stretched beyond manufacturer’s tolerance). o OCSD also noted the hot water pipe has experienced significant movement. o B&V/BC observed the hot water loop piping with OCSD during the November 30 site visit and there does appear to be significant movement in the piping system. It is not possible to visually assess whether this movement is excessive. o B&V/BC recommended that a comprehensive inspection and evaluation be performed of the hot water loop to determine if improvements or modifications are needed. OCSD concurred. o In the interim, OCSD’s conditions assessment team can look at hot water piping now to see if any specific repairs are recommended, such as repair of the piping insulation. 3) Evaluate Adding Digester Capacity o B&V/BC noted that per the OCSD White Paper, the Plant 1 digesters are projected to be at capacity in Year 2035, even after IRWD stops sending sludge to Plant 1 and even with the new P1-101 thickening and dewatering facilities. o Digesters #5 and #6 need to be maintained as digested sludge holders. o In TM-7, B&V will note the potential digester capacity concerns and will recommend a future capacity evaluation after projects P1-100 and P1-101 are completed and enough thickening centrifuge performance data has been accumulated (in approximately 2-3 years). 4) Evaluate Primary Sludge Diversion Line to Plant 2 o Currently, the only way to divert solids from Plant 1 to Plant 2 is to discharge settled primary sludge to the interceptor sewer going to Plant 2. These solids must be re-settled at Plant 2. Also, the current arrangement reduces the capacity of the interceptor sewer.

The above represents the author’s understanding of the items discussed and the decisions made during the context of the meeting. All items are assumed to be correct if the author is not contacted with clarifications.

B&V Job 190875 PS15-01 No. OCSD BIOSOLIDS MASTER PLAN Date: January 3, 2016

FINAL MEETING MINUTES Page: 5 of 6

No. Item Action By Due Date o In TM-7, B&V will note the concerns with the temporary diversion, list the benefits of a dedicated sludge diversion to Plant 2, and will document that the sludge diversion line was previously evaluated in project P1-101A. o A separate sludge diversion line would offer OCSD significant operational flexibility in shifting sludge load between Plant 1 and Plant 2 digesters. Therefore, B&V is recommending that a dedicated sludge diversion line be re-evaluated in the future. o OCSD will provide B&V/BC with the previous sludge OCSD Complete diversion line evaluation from P1-101A. o It is recognized that this may be a costly alternative and there may be significant constraints in terms of pipeline easements and land area availability. 5) Evaluate Drying Bed Modifications o B&V/BC noted that the use of drying beds for grit dumping is causing operational challenges. The V- shape of the beds requires drivers to stand downhill of the dumping area. Also, the trench drain gets clogged frequently. o Operations staff would like to use the drying beds to for both sludge drying and grit dumping. o In TM-7, B&V will recommend an evaluation of the drying beds. o Modification of the drying beds could be handled as an FE project. Alternately, the beds could be relocated as part of a larger project and would be re- designed at that time.  In TM-7, it was decided to list all biosolids related projects for Plant 1 that have been identified in other studies. No detailed description is needed – just identify these biosolids projects for completeness.  OCSD noted that DAFT demolition should be included as a BMP CIP project. OCSD noted that project X-043 is in the works, which may cover DAFT demolition work. OCSD will provide details of project X-043 (description, OCSD Complete cost, and schedule) to B&V. In TM-7, B&V will summarize X-043 project and describe the current status of the project.  OCSD requested that the X-403 project include demolition of the TWAS piping between DAFTs and Digesters.

The above represents the author’s understanding of the items discussed and the decisions made during the context of the meeting. All items are assumed to be correct if the author is not contacted with clarifications.

B&V Job 190875 PS15-01 No. OCSD BIOSOLIDS MASTER PLAN Date: January 3, 2016

FINAL MEETING MINUTES Page: 6 of 6

No. Item Action By Due Date

6 TASK 7 NEXT STEPS  B&V/BC reviewed the Task 7 scope of work and noted that the following items may be deleted since no new facilities are being recommended at Plant No. 1 for this BMP: (1) geotechnical investigation and feasibility study; (2) evaluation of SP-141 design criteria; and (3) evaluation of CenGen capacity. OCSD concurred.  B&V/BC will present Draft TM-7 at the January 17 meeting and the final TM-7 will be completed after OCSD’s review and resolution of any comments.

7 ACTION ITEMS  B&V/BC will forward the cake silo storage evaluation B&V/BC Complete table to OCSD.  OCSD to provide B&V with sludge diversion pipeline OCSD Complete evaluation from P1-101A.  OCSD to provide B&V with project X-043 details, which OCSD Complete will be summarized in TM-7.

The above represents the author’s understanding of the items discussed and the decisions made during the context of the meeting. All items are assumed to be correct if the author is not contacted with clarifications.

B&V Job 190875 PS15-01 No. OCSD BIOSOLIDS MASTER PLAN Date: January 20, 2017

FINAL MEETING MINUTES Page: 1 of 4

Meeting Location: Plant No. 1 Conference Room A Meeting Date: January 17, 2017 Meeting Time: 12:30 PM to 1:30 PM Meeting Topic: Task 7.3 – TM 7: CIP Project Development for Plant No. 1 Solids Handling Facilities Revision Date: Authored By: Jake Holden, Jim Clark, and Dan Buhrmaster

Attendees: OCSD Team Black & Veatch/ Brown and Caldwell Team Sharon Yin Michelle Hetherington Jim Clark – Black & Veatch Jeff Mohr Eros Yong Dan Buhrmaster – Black & Veatch Kathy Millea Tom Meregillano Jake Holden – Black & Veatch Kevin Hadden Daisy Covarrubias Tom Chapman – Brown and Caldwell Dan Bunce – Brown and Caldwell Andrew Tran – Brown and Caldwell

Handouts: None

The key points that were discussed in the meeting are summarized below and follow the order of the meeting agenda. Some points may not be recorded in the same sequence as actually discussed. Action items are noted below and will be included in the Action Item Log.

No. Item Action By Due Date 1 OVERVIEW AND MEETING PURPOSE  B&V/BC provided an overview of Task 7 and explained that the purpose of the meeting was to present TM 7, including the recommendation on post-dewatering facilities, and discuss the development of Plant No. 1 CIP projects/evaluations. 2 SAFETY MOMENT  B&V/BC provided a safety moment on applying safety practices from the job site to home repair, such as locking out electrical devices during work and identifying hazardous materials. 3 PRESENT TM 7 – CIP PROJECT DEVELOPMENT FOR PLANT NO. 1 SOLIDS HANDLING FACILITIES  B&V/BC presented the contents of TM 7.  B&V/BC noted that much of the TM7 material was presented during the 12/20/16 meeting and 6 hard copies of TM7 have been provided to OCSD. a) Plant No. 1 Post-Dewatering Evaluation

The above represents the author’s understanding of the items discussed and the decisions made during the context of the meeting. All items are assumed to be correct if the author is not contacted with clarifications.

B&V Job 190875 PS15-01 No. OCSD BIOSOLIDS MASTER PLAN Date: January 20, 2017

FINAL MEETING MINUTES Page: 2 of 4

No. Item Action By Due Date o B&V/BC noted that Plant 1 digesters do not have the same structural concerns as Plant 2 digesters and there are no current drivers that would require replacement of the digesters. o B&V/BC presented the non-economic CDP analysis of Plant 2 and noted it would be similar to Plant 1, noting that partial drying was the least favorable alternative and less favorable compared with thermal drying. o B&V/BC noted the team’s recommendation to only evaluate thermal drying. OCSD concurred. Decision o B&V/BC presented a potential site layout for the dryer building, noting that it would require a large footprint, would be further from the thickening/dewatering building than preferred, and would take up valuable space for future facilities. o B&V/BC presented a summary of the SWEET analysis and the final NPV costs for the baseline alternative (no drying) and the thermal drying alternative. The baseline alternative was about $14M lower than the drying alternative. o B&V/BC recommended no post-dewatering (thermal drying) facilities at Plant 1. OCSD concurred. Decision b) Plant No. 1 Solids Handling Facilities Issues and Future Projects/ Studies Recommended o B&V/BC presented the Plant 1 solids handling CIP development portion of the TM. o B&V/BC noted the current solids handling CIP projects: Gas Facilities Improvements(J-124) and the Plant 1 DAFT demolition and OCSD advised that neither need to be further discussed in the BMP. o B&V/BC to develop gas projections for Plant 1 based on White Paper flows/loads and compare to the SP- 141 gas design basis to determine if any B&V 1/31/17 modifications to the SP-141 equipment recommendations are needed. o B&V/BC also presented the results of the Plant 1 cake silo storage evaluation and the five recommended future evaluations. o B&V/BC noted the cake silo storage evaluation showed that adequate capacity (> 3.5 days) is available in the cake silos over a 25-30% range in dewatered cake solids concentration. Therefore, no

The above represents the author’s understanding of the items discussed and the decisions made during the context of the meeting. All items are assumed to be correct if the author is not contacted with clarifications.

B&V Job 190875 PS15-01 No. OCSD BIOSOLIDS MASTER PLAN Date: January 20, 2017

FINAL MEETING MINUTES Page: 3 of 4

No. Item Action By Due Date additional cake storage is recommended. OCSD concurred Decision o B&V/BC discussed the recommended Digester Solids Screening evaluation and noted that the two potential locations for the screens would be in the sludge circulation loop or upstream of the sludge blending tanks. B&V/BC recommends that this evaluation be started soon with high priority. o B&V/BC discussed the recommended Hot Water Loop evaluation, noting that the expansion joints may have been extended beyond the manufacturer’s tolerance, there is piping movement that should be evaluated, and that some of the insulation has been damaged. It is recommended that this evaluation be started soon with a medium priority. o OCSD recalled hearing that this issue may already be under an existing FE project. OCSD to check with Rich Leone on status of FE project. OCSD Completed o POST MEETING NOTE(1/19): SY confirmed with Rich Leon that FE15-09 is repairing the entire hot water loop system. o B&V/BC to move the hot water piping under Section 3.3 (O&M Identified Issues and Solutions) and state FE15-09 will fix them. B&V 1/31/17 o B&V/BC discussed the recommended Digester Capacity evaluation, noting that the White Paper, Condition 1 flows/loads will push the digesters to their capacity and that additional digesters should be evaluated. OCSD noted that the evaluation would take place after P1-101 thickening centrifuge performance data is available. This evaluation is considered a high priority. o OCSD noted that P1-100 may not have provided a permanent fix (extend life to 20 years) to some of the existing digester domes and some may need additional repair or replacement in 5 to 10 years. o OCSD to check internally to confirm whether or not OCSD Completed replacement of some digester domes is required. o POST MEETING NOTE(1/19): SY confirmed with Adam Coghill that P1-100 permanently repaired the digester domes and that no CIP project is required. o B&V/BC discussed a potential Sludge Diversion

The above represents the author’s understanding of the items discussed and the decisions made during the context of the meeting. All items are assumed to be correct if the author is not contacted with clarifications.

B&V Job 190875 PS15-01 No. OCSD BIOSOLIDS MASTER PLAN Date: January 20, 2017

FINAL MEETING MINUTES Page: 4 of 4

No. Item Action By Due Date Pipeline to Plant 2 evaluation noting that OCSD would prefers a dedicated sludge line that discharges primary sludge into the Plant 2 sludge blending facility for operational flexibility. However, this may be cost prohibitive and there will be challenges locating a potential corridor for this pipeline. The sludge line should be included as an alternative to expanding digestion under Section 3.2.4 (Digester Capacity Evaluation). o B&V/BC will move the Plant 1 to 2 sludge diversion pipeline option to Section 3.2.4 and include it as an B&V 1/31/17 alternative to expanding the digester capacity at Plant 1. o B&V/BC discussed the Existing Sludge Drying Bed Modifications evaluation, noting that OCSD would like the beds designed for both grit dumping and sludge drying. This project will likely be combined with another project in the future. o B&V/BC discussed other issues identified by O&M that will not be further discussed in the BMP including: Digester Roof Coating Repair, Obsolete Boiler Demolition, Backup Water Sources for Digester Gas Compressor, Condition of Ferric Piping/Pumps to Digesters, Repair Deficiencies Identified During P1-100 Work, and Repairing WEMCO Mixing Pumps. c) Implementation Schedule and Sequencing o B&V/BC presented a table showing a potential implementation schedule and sequencing. d) Conclusion and Next Steps o B&V/BC noted that TM 7 concluded that post- dewatering at Plant 1 is not recommended. B&V/BC noted that the five recommended solids handling evaluations could result in Plant 1 CIP projects in the future. 4 TASK 7 Look Ahead Schedule  B&V/BC requested OCSD’s TM 7 comments in 4 weeks – by February 14.  B&V/BC presented a table showing the status of each TM and the Draft BMP. 5 ACTION ITEMS  See previous sections for action items.

The above represents the author’s understanding of the items discussed and the decisions made during the context of the meeting. All items are assumed to be correct if the author is not contacted with clarifications. Orange County Sanitation District | TM‐7: CIP Project Development for Plant No. 1 Solids Handling Facilities

Appendix D – QC Review Affidavits The following is a copy of the QC affidavits, which are signed by the following people who reviewed TM‐7:

 Matt Thomas (B&V)  Dan Buhrmaster (B&V)

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