Organics to Energy Program. On the Way to Clean Energy from Wastewater

Transcription

1 Organics to Energy Program On the Way to Clean Energy from Wastewater

2 Environmental Services - Learning to love lemonade Central Treatment Plant is underutilized Fuel costs are high and variable Solid Waste Management goal: 70% diversion from landfill by 2028 Tacoma area is an air quality maintenance zone Greenhouse gas emissions 2

3 3 Developing Synergy in Partnership Wastewater Utility Surface Water Utility Solid Waste Utility

4 Tacoma s Waste Composition

5 FoodCycling Made Easy Tacoma Brown Bucket Brigade

6 A Winning Combo! Simple System Food Only Comprehensive Outreach

7 Overview: a new attitude From Waste Management to Resource Management Food waste is a valuable resource Divert food waste from landfill for higher purpose Use excess capacity at treatment plant to produce Methane (RNG) Capture methane (RNG) to use as vehicle fuel Convert City Fleet to CNG 4

8 Organics to Energy Program 3

9 Gas Production On average the equivalent of 1,000 gallons of diesel is flared each day. 5

10 $/DGE $0.00 $1.00 $2.00 $3.00 $4.00 $5.00 $6.00 Transportation Fuel Projected Costs Source, US Energy Information Administration, Annual Energy Outlook 2014 (2015 dollars per Diesel Gallon Equivalent, unless otherwise noted) Diesel Propane E85 Gasoline Natural Gas 200 scfm Biogas Production Source, US Energy Information Administration, Annual Energy Outlook 2012 (2012 dollars per Diesel Gallon Equivalent, unless otherwise noted)

11 Renewable Identification Number (RIN) Credits Credits are purchased by oil companies to show they are meeting their obligation to use renewable fuels as required by the Energy Independence and Security Act (2007) RINs are a traded commodity with volatile prices, currently about $0.50 per dieselgallon equivalent 7

12 Business Plan Divert food waste from landfill to the Central Treatment Plant, increasing Renewable Natural Gas (biogas) production Position Environmental Services as a wholesale provider of renewable natural gas vehicle fuel by installing equipment to condition digester gas to CNG engine manufacturers specifications Develop a public-private partnership with a fuel distributor to vend biogas at their facilities Receive RIN credits for each gallon-equivalent sold for vehicle use 8

13 Sounds Great But Wastewater concerns: Foaming in ATAD process with low ph materials Ability of food waste to induce auto-heating Impacts on quality of TAGRO products Solid Waste concerns: Equipment operations Materials management Processing, storage, odors Foaming in ATAD Quad 2 at CTP TAGRO Blending Facility 9

14 Pilot: Commercial Food to 15 ATAD Goals 1. Evaluate the viability of food waste diversion and digestion 2. Determine feasibility of simultaneously increasing gas production and waste diversion 3. Demonstrate that food waste will not adversely affect TAGRO

15 Market Analysis: Start with Commercial Food Waste Pilot 750-1,000 commercial food waste generators in Tacoma 65 participating in pilot program City provides containers tons per week 600 tons collected in

16 DODA MiniBioseparator -- Selected Technology Reject materials carried up the mill Auger feeds food waste from hopper to mill Pulp extruded through screen 12

17 Loading the Grinder (before) 18

18 19 Pilot Study Results No adverse effects to TAGRO One ton of food waste yields about 3,600 ft3 of RNG (equivalent of about 13 gallons of diesel) Odors can be controlled Food waste can be used to stabilize plant load Fibrous organics should be excluded Modify pilot study equipment to allow year-round operation Reject material from DODA.

19 Loading the Grinder (after) 20

20 Residential Disposers Study - Wapato Lake Pre- and post-sorting of household waste revealed: Food disposed in the garbage per household decreased 14% from 25.9 lbs. to 22.4 lbs. Food placed in with the yard waste decreased from 4.6 lbs. to 0.5 lbs., a reduction of 89%. 21

21 Wapato Lake Results Majority (78%) reported no problems. Problems reported were: jams, clogs (15%) noisy (5%) broken (3%) odors (3%) Fats, oils, and grease disposed of in trash (97%). 90% were satisfied or very satisfied with program. Nearly 60% reported using the FWD almost always in meal prep and cleanup; 75% reported they put all or most food waste down FWD. 86% reported a decrease in trash 22

22 Clean Fuel Implementation Grant submittal for biogas equipment March 2016 Solid Waste CNG fueling facility online in 2015 Bio-CNG facility preliminary design complete City currently ordering dual fuel light vehicles. Solid Waste has purchased 10 CNG trucks with 10 more on the way by end of 2016 and Wastewater fleets converted over time according to replacement schedule 16

23 Potential Benefits Helps keep utility rates low by: Reduces and stabilizes fuel costs Renewable Identification Number (RIN) revenue Better utilization of plant infrastructure Reducing material sent to landfill Augment nutrients to treatment plant Greater operational resilience Helps the environment by: Increases life of landfill Reduces greenhouse gas emissions Reduced air emissions (particulates) Builds Tacoma s reputation for Green Innovation 14

24 Questions? Jim Parvey, P.E., LEED AP Office of Environmental Policy and Sustainability (253)