Solids Master Plan Briefing June 22, 2017 Meeting Agenda Review of - - PowerPoint PPT Presentation

Solids Master Plan Briefing

June 22, 2017

Meeting Agenda

 Review of Master Plan Process  Status Update  Technology Selection  Budget & Next Steps  Discussion

Review of Master Plan Process

Master Plan Process - Where Are We Now?

• Fall 2015
• Prioritize needs
• Narrow down

choices

Set and Rank Criteria

• Winter 2016
• Look at

Immediate needs

Condition Assessment

• Spring/Summer

2016

Develop Alternatives

• Fall 2016-

Winter 2017

Final Report

Ongoing outreach to stakeholders Ongoing peer review COMPLETED! COMPLETED! WE ARE HERE COMPLETED!

Solids Master Plan: Evaluation Process



Workshop 1 - Kickoff and Project Objectives Defined



Workshop 2 - Define Screening and Evaluation Criteria



Workshop 3 - Technology Identification and Screening



Workshop 4 - Process Specific Analysis



Workshop 5 – Alternative Train Development and Preliminary Findings : Selection of top 4 alternatives



Workshop 6 – Weighted Criteria Ranking of Alternatives



Workshop 7 – Final Plan Recommendations

Universe of Technologies Screened Technologies and Process Analysis Top 4 Selected Alternatives

Ranking and Final Evaluation

Recommended Plan

Status Update

We’ve Been Busy!

 Fall 2016  Initiated Virginia Tech lab-scale digestion pilot  Toured UOSA (Centreville) to learn more about their Solids

Handling process

 Winter 2017  Updated DES leadership on the Solids Master Plan process  Met with WSSC (Prince Georges and Montgomery Counties) to

learn more about their Master Planning process

 Held meetings with WPCP staff on the Solids Master Plan status,

and solicited feedback on alternatives

We’ve Been Busy!

 Spring 2017  Met with County Manager, Mark Schwartz, on Solids Master Plan  Presented the Solids Master Plan process to industry leaders  Presented to Arlington County community members – CivFed,

ACE, E2C2, FAAC, NCAC, AHCA

 Optional Meeting with Stakeholders to discuss emissions,

regional solutions, and financing

Virginia Tech Study

 Arlington County partnered with

Virginia Tech to research which anaerobic digester operating conditions and dewatering methods resulted in optimized gas production and reduced odors.

Virginia Tech Study

 The results found that Arlington’s

raw sludge are within the expected range for gas production and methane content.

 Variables such as dewatering

method, polymer dose, and storage time all impacted odor production.

 The results showed that Arlington’s

digestion process would be more stable than industry standards.

Technology Selection

Top Four Alternatives

Name Biosolids quality Major features Lime Stabilization rehab-only Class B What we have now; highest amount of biosolids and trucks; no gas production; odorous Anaerobic Digestion (AD) Class B Biosolids volume lower; gas production; fewer odors Thermal Hydrolysis (THP) + Anaerobic Digestion Class A Biosolids volume reduced further; more gas production; fewer odors Anaerobic Digestion + Heat Drying Class A Least amount of biosolids; no net gas production; fewer odors

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5.85 8.06 6.71 6.12 14.70 14.07 11.79 12.07 7.78 9.09 10.14 8.76 3.04 4.77 5.56 5.43 5 10 15 20 25 30 35 40 Lime AD THP+AD AD+DRY ECONOMIC OPERATIONAL ENVIRONMENTAL SOCIAL

AD HAS HIGHEST OVERALL SCORE THP+AD IS SECOND OVERALL

Weighted Criteria Ranking Summary

Scores are very close; do not provide clear direction on path forward THP + AD highest on social and environmental

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Benefits of THP/MAD Compared MAD

 Pathogen Reductions: Meets Class A (higher

quality) standards

 Fewer, smaller digesters: Thermal hydrolysis

greatly reduces the volume of the digester tanks – from 32

 Higher rate of methane production: More

energy generation

 Increased dewaterability: THP biosolids are

easier to dewater and require less polymer

 Reduced trucking: THP reduces the quantity

• f biosolids

Alt 3: Recommendation to County Manager

Primary Sludge Secondary Sludge Holding/ Blending/ Tank(s) Screening and Pre-Dewatering

Anaerobic Digestion

Dewatering Land Application or Distribution and Marketing (Class A) Biogas to Utilization Centrate To Headworks CentrateTo Headworks Cake Hopper Holding Tank Cake Storage THP Reactors Steam Generator

Benefits of Class A Biosolids

 Greater public acceptance  More outlets for distribution: land

application, soil amendment, revenue stream…

 Less land application restrictions than Class

B biosolids

 Pathogen reduction – over 90% lower than

Class B requirements

 Rigorous testing to ensure compliance  Reduced hauling costs

DC Metro Region Biosolids Trends

76.10% 43% 12.10% 39.80% 0% 10% 20% 30% 40% 50% 60% 70% 80% 2010 2016

Percentage of Class A and Class B Biosolids over time in Mid-Atlantic Region

Class B Class A

County Opportunities

 BIOSOLIDS IN OUR COMMUNITY  Class A option can be used as an organic soil

amendment – soil blends created now like Milorganite (Milwaukee) or Bloom (DC)

 High nutrient content of biosolids means

little or no use of chemical fertilizers

 ENERGY RECOVERY POSSIBILITIES  Energy Recovery On-Site – Combined Heat and Power (CHP)  Energy Recovery using biogas derived fuels is of interest to County

Transit Bureau - ART Bus Fleet runs on compressed natural gas (CNG) – New ART fueling station being constructed across the street from the Plant

 Looking at digesting other organic wastes in future – would result in

greater gas production

Budget and Next Steps

Utilities Fund is an Enterprise Fund

 Enterprise Funds are self-sufficient.  Water-sewer rate set at level which, along with other

revenues including excess fund balance, will fully fund activities.

 Ensuring that the rate stays at an affordable level is a key

goal of managing this fund.

 Utilities Fund must balance the needs on the water and

wastewater sides

 Capital Improvement Plan (CIP) process for FY2019-28 will

start in the fall and be adopted in July 2018.

• 5,000,000

10,000,000 15,000,000 20,000,000 25,000,000 30,000,000 35,000,000 40,000,000 45,000,000 FY16 FY17 FY18 FY19 FY20 FY21 FY22 FY23 FY24 FY25 FY26 FY27 FY28 FY29 FY30

Projected Utility Fund Annual Debt Service w/o Water Project

Existing VRA Debt Existing GO Debt Plant Debt Service (includes Solids Master Plan THP/AD) FY17-26 CIP Water & Sewer Infrastructure Debt Service

Next Steps – Short Term (Next Two Years)

 Finalize Master Plan Report  Air Quality Study – Emissions from sources associated

with CNG and CHP options

 Further Exploration of Regional Solutions

 Meetings with DC Water

 Determine proposed end use for biogas (CNG or CHP)  Continue Phase 1 SMP Design  Finalize timing of Phases 2 and 3 (depending on

Washington Aqueduct decisions)

 Hold periodic update meetings with stakeholders

Next Steps – Longer Term (Next 3-5 Years)

 Review Solids Master Plan Report  Conduct negotiations with outside entities:

DC Water, Washington Gas, and/or ART/WMATA bus facilities

 Hire a Design Engineer  Begin Design of Phase 2 and Phase 3 Projects  Hire a Construction Manager  Prepare drawings and specifications for construction  Hold periodic update meetings with stakeholders

DISCUSSION