Total Makeover for Biosolids Handling at DC Water s Blue Plains Advanced Wastewater Treatment Plant. February 2015

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1 Total Makeover for Biosolids Handling at DC Water s Blue Plains Advanced Wastewater Treatment Plant February 2015

2 Today s Makeover Will Include Recent History of Blue Plains Solid Handling Processes Evolution of the New Plan Implementation Future Use of Final Product Brown and Caldwell 2

3 Recent History 370 MGD (ADWF Capacity) >1B hydraulic capacity 550 MG primary treatment Total Nitrogen Old 7.5 mg/l New 4.2 mg/l Phosphorus to.18 mg/l Clean Rivers Program 4 tunnels, 96% elimination of overflows Brown and Caldwell 3

4 Recent History Solids Processing of Three Different Sludges Gravity Thickeners (Primary Sludge) DAFT Bldg. (Biological Sludge) Centrifuge Dewatering Class B Cake Loadout Lime Biosolids Program Site (6.5 acres) Brown and Caldwell 4

5 Recent History Biosolids Handling Collect 3 sludges primary, secondary, nit/denite Add lime ~ 20% by volume Mix Dewater with centrifuge Haul away Brown and Caldwell 5 5

6 Recent History Class B Sludge 1200 wet tons/day (65 20-yard trucks) Lime addition adds 15% to the total volume Haul distances kept increasing Brown and Caldwell 6

7 Risks and Costs An Annual Concern DC Water s Risks and Costs Were Increasing Yet farmers were Lovin It Haul miles increased due to lime, metals, and nutrient limitations Virginia concerns over Class B and non- Virginian sludges Brown and Caldwell 7

8 The New Plan Brown and Caldwell 8

9 The New Plan Desired Goals Alternative Development An International Panel of Experts Establishment of Goals Class A Product (Pathogen Destruction) Low Odor Reduce Biosolids Mass/Volume (Anaerobic Digestion) Utilize Gas Selected Alternative Thermal Hydrolysis with Anaerobic Digestion Brown and Caldwell 9

10 The New Plan Gravity Thickeners DAFTs Power Emissions R R Biogas Treatment and CHP Steam Biogas Blend Tank Screening and Pre-Dewatering R Cambi THP Mesophilic Anaerobic Digestion Final Dewatering Loadout Lime Recycle Processing Dewatering Mix Store & Loadout R Class A R Class B Brown and Caldwell 10

11 The New Plan Procurement Method 75 years design-bid-build DC Water indicated design-build was an option Decrease design and construction time (surveys confirmed) Reduce overall costs (all parties including DC Water) Benefit from contracting innovation (limited) Prescriptive specifications Site limited Existing operations Brown and Caldwell 11

12 The New Plan Four Components and Three Delivery Methods Gravity Thickeners R R DAFTs Power Emissions Biogas Treatment and CHP Combined Heat & Power Design-Build-Operate Site Preparation Site Prep Design-Build-Build Steam Biogas Main Process Train Design-Build Blend Tank Screening and Pre-Dewatering R Dewatering Cambi THP Lime Mix Mesophilic Anaerobic Digestion Store & Loadout Belt Filter Presses Recycle Processing R Loadout Class A Final Dewatering Design-Build- Build R Class B Brown and Caldwell 12

13 Main Process Train Project Highlights MPT processing all of DC Water s ~300 dry tons produced per day All 4 digesters are receiving sludge with full mixing Digesters producing a quality (62% methane) biogas at an estimated rate of 2800 cubic feet per minute Performance Testing for MPT began in January 2015 with 4-5 months duration flow through, mixers, class A, COD reduction, HEX, air permit Status: 99% Complete Brown and Caldwell 13

14 Combined Heat and Power (CHP) Project Highlights Auxiliary boiler on natural gas Turbines estimated to go on-line late April Temporary boilers being used as a standby Blowers, moisture removal, RO, deaerator, siloxane removal all tested Status: 95% Complete Brown and Caldwell 14

15 Final Dewatering Project Highlights Trains A&B in operation; trains C&D in January Early dewatering results 28-30% - optimization later. Polymer dosage lower than expected Status: 91% Complete Brown and Caldwell 15

16 Implementation Project Cost: Construction Cost: $400 Million 40% DC, 60% Area Users ROI (Return on Investment) Years or Dollars Project has not impacted the rate payers Savings more than enough to pay off bonds Brown and Caldwell 16

17 Implementation What Are All the Financial Benefits? Cost Savings Process Model: $10-15 Million (was 30 mil early on) Power savings of 10 MW net Haul cost: Only the volume decrease has been claimed Labor: Fewer new staff might increase the savings Chemical cost: No lime cost, lower polymer demand No end use credits in model Brown and Caldwell 17

18 Implementation Benefits not claimed as Financial Benefits yet Class A Biosolids More options and less hauling Biogas Turbines combust a greenhouse gas RECs maybe 1.7 mil Total Volume of Biosolids for Disposal Down 50% Total Carbon Footprint Reduced by 40% All Benefits are On Target! Brown and Caldwell 18

19 Future for the Project On-site Room for Four More Digesters FOG Program Co-Digestion No landfills 1000 lbs of foodwaste/month do something! Cambi Data Indicating Early Designs Conservative Supports Energy Neutrality Brown and Caldwell 19

20 Future for the Project Potential Use of Biosolids Use in tree planting (reduces runoff) Bioretention mixes Restoration projects Green roofs (reduces runoff) Urban gardens & farms Golf courses Employee and citizen use Partnering with civic groups, DC and federal agencies, environmental groups, etc. Carbon sequestration Brown and Caldwell 20 20

21 Questions Brown and Caldwell 21