From Alternative Daily Cover to Anaerobic DigestionFrom Alternative Daily Cover to Anaerobic Digestion

California is the only state in the nation that counts the use of green waste alternative daily cover (ADC) at a landfill as landfill diversion, which qualifies as recycling. With green waste landfill bans on the books in 21 states, California is once again considering phasing out green waste ADC as landfill diversion credit by 2020 in the upcoming 75 percent Recycling Plan prepared by the state agency, CalRecycle, in a report which was due to the California Legislature on January 1, 2014. Plus, the California Air Resources Board (CARB) will be considering diverting from 50 percent to 75 percent of all organics from landfills by 2020 as part of the California Global Warming Solutions Act of 2006 (AB 32).

As California steps up to phase out organics from landfills, a few states have overturned green waste landfill bans to support disposal where there are landfill-gas-to-energy systems installed to create energy from the biomethane. Instead of developing biomethane in landfills that could take up to 30 years to realize, emerging anaerobic digestion (AD) technology is being commercialized throughout the United States today that can capture biomethane within 30 days and generate electricity and/or produce carbon negative transportation fuels. Now, 20 years after the passage of the green waste recycling ADC policy, California is poised to make the technological leap from ADC to AD while supporting and developing the compost infrastructure.

Green Waste ADC, Uncovered

Green waste ADC was deemed landfill diversion by the California Integrated Waste Management Board (CIWMB) in December 1993, and counted ADC as recycling since there were few composting facilities at the time with complex permitting, and unproven markets. The policy, AB 939, was to sunset in 1997, and afterward only count toward 7 percent of the 25 percent landfill diversion required of California cities in 1995, and 50 percent of diversion required in 2000. The Natural Resources Defense Council (NRDC) filed a lawsuit against the CIWMB claiming that counting ADC use as diversion was not legal. NRDC argued that the CIWMB compromise resolution was a Solomon-like decision that cut the ADC baby in half; allowing limited diversion credit with a sunset was arbitrary and capricious. 

By that time, large landfills were hooked on green waste ADC to deliver cost-effective landfill diversion to their client cities to comply with AB 939. The landfill industry sponsored AB 1647 (Bustamante) in 1996, which stated that the use of waste-derived ADC constitutes diversion through recycling. AB 1647 required the CIWMB to pass regulations encompassing past policies and established performance standards and limitations on maximum functional thickness necessary to ensure protection of public health and safety consistent with state minimum standards.

In 1998, California Code of Regulations Title 27 was adopted, which allows 11 types of ADC materials, as listed below, to be used at landfills as ADC within defined specifications, where landfill diversion credit, or recycling, was permissible for the waste-derived ADC: 

Since 1998, ADC use must be approved in writing by the County Health Department, acting as the local enforcement agency for the state, prior to use at solid waste landfills, consistent with the California Code of Regulations. The regulations also allow alternative intermediate cover (AIC) and beneficial reuse at landfills where it would still count as recycling. AIC is the compacted one-foot layer between landfill lifts. Beneficial reuse could consist of the use of mulch as erosion control or C&D as wet weather pads.

Green waste ADC was increasing at an average of 300,000 tons per year after the regulations were in place, and peaked in 2005, with more than 3 million tons being landfilled as ADC. It then started to decline by an average of 300,000 tons per year. By 2011, green waste ADC use was less than 1.7 million tons, a decrease of 43 percent in seven years, as tracked by the state agency, CalRecycle, and referenced in the included chart. ADC use by material types are listed from a peak in 2005 through 2011, where C&D material is up to 750,000 tons per year, sludge hovers around 300,000 tons per year and auto shredder fluff averages more than 600,000 tons per year. 

Leaving the Landfill

Green waste used as ADC has dropped over the years for a variety of reasons. Many landfill operators have shifted their green waste ADC tons to AIC or beneficial reuse, keeping landfill diversion credit without being subject to type of transparent reporting required for ADC. Other reasons for the green waste ADC decline may include residential co-collection of food waste with green waste, California droughts, economic recession, increased capacity at compost facilities and increased green waste mulch to land application.

The co-collection of residential food waste with green waste disallows its use as ADC. Green waste use as ADC is anticipated to continue to decline with the closure of the Puente Hills Landfill on November 1, 2013, sending 900 tons per day of green waste ADC or about 275,000 tons per year to other uses. Just years ago, the closure of the once-largest landfill in the nation would have been shocking. While the garbage was absorbed by nearby county landfills, green waste diversion destinations have been spotty. California has done a great job permitting over 1.5 billion tons of remaining landfill capacity, and will now focus on composting and AD.

ADC policies and legislation are back in 2014. Under new rules, green waste could still be used as ADC but would not count as recycling after 2020. Other types of ADC can still be used. So while there would be no ban on green waste ADC, higher and better uses are planned. Composting and AD facilities are being developed to receive the 1.7 million tons of green waste ADC that was disposed of in 2011, as well as those AIC and beneficial reuse green waste tons that are not posted.

The CalRecycle 75 Percent Recycling Plan that was scheduled to be delivered to the legislature on January 1, 2014 would not count any type of ADC as recycling, and would be a major factor in lowering the current statewide AB 939 landfill diversion rate of 66 percent in 2012, to a more realistic 50 percent. CARB will adopt the Scoping Plan 5-Year Update this spring as part of the California Global Warming Solutions Act of 2006 (AB 32), and will target landfilled organics. The focus will be on anaerobic digestion and composting. CARB has projected that up to 3.75 million tons of organics could go to AD by 2020, and another 3.75 million tons could go to compost facilities by 2020, moving up to 7.5 million tons of organics per year.

CARB has determined that producing renewable compressed natural gas (CNG) from dry fermentation AD is carbon negative, with a carbon intensity of minus 15. The collection industry in California is gearing up to field a carbon negative fleet consisting of over 15,000 heavy-duty vehicles by 2020.

Growing Infrastructure

Further developing the organic infrastructure is critical, as state policies for funding are being proposed within the billion-dollar AB 32 cap-and-trade program. The California Compost Coalition has submitted a white paper to CARB to fund the development of compost facilities and anaerobic digestion facilities with cap-and-trade money. Anticipating the future goals, CalRecycle released the Final Program Environmental Impact Report (EIR) for Anaerobic Digestion Facilities where it was assumed that there will need to be 70 AD facilities processing 50,000 tons of organic waste by 2020, achieving close to the 3.75 million tons per year of organic material needing to be diverted to AD by 2020. CalRecycle also released the Organic Road Map, where it was assumed that there will need to be 28 more composting facilities processing 500 tons per day to divert up to 3.75 million tons per year to composting by 2020. With 1.67 collection jobs and 0.5 processing jobs per 1,000 tons, the 7.5 million organic tons could result in 16,000 new jobs. 

CARB has prepared an investment plan on using the AB 32 cap-and-trade proceeds to fund the development of the compost and AD industry. Anaerobic digestion is at the nexus of AB 32 by diverting organic waste and producing renewable energy and carbon negative transportation fuel, while making compost to be used for sustainable agricultural in disadvantaged communities. Governor Brown plans to release his 2013-2014 budget in early January that will specify the investment in AD, on top of the $25 million per year that the California Energy Commission has been providing in grant funding.

By 2020, green waste ADC use that counted as recycling for 27 years will be diverted to AD and compost.  

Evan W.R. Edgar is the Principal of Edgar & Associates, Inc., a lobbying firm and environmental engineering firm based in Sacramento, Calif., specializing in solid waste management, recycling, composting and renewable energy issues.