Converting green waste to hydrocarbons
In April, the City of Hoover, Alabama officially became the first community in the United States to fuel their municipal vehicles with E85 ethanol made from wood waste collected from city public works projects and curbside collection of yard debris.
“To our knowledge and according to the United States Department of Energy, it is the first true application where it is actually fueling vehicles,” said Mark Bentley, executive director of the Alabama Clean Fuels Coalition. This coalition is among 90 “Clean Cities” state-based organizations established under the umbrella of the United States Department of Energy in 1993 to facilitate voluntary public-private partnerships to create viable markets for clean, alternative fueled vehicles.
Hoover, a suburban community just south of Birmingham is the state’s sixth largest city with a population just over 75,000, but leads the state, perhaps even the nation in the per capita use of alternative fuels for municipal vehicles. Of all Hoover’s municipal vehicles, 88 percent are now powered by E85 ethanol, electricity, commercially purchased B20 biodiesel and biodiesel produced from recycled cooking oil donated by citizens and restaurants. ...read more
FOCUS on WOOD/GREEN WASTE
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According to the United States Environmental Protection Agency (EPA) and various large municipal solid waste agencies, green waste such as yard trimmings, arborist cuttings and food residuals constitute from 25 to 30 percent of the American municipal solid waste stream. That’s a lot of biomass going to landfills that could otherwise become useful, environmentally beneficial compost, or feedstock for ethanol production.
Green waste is widely used at landfills as alternative daily cover (ADC) as a substitute for dirt and other material. But there are many options for ADC. For example, besides green waste and compost, California’s Integrated Waste Management Board (CIWMB) approves ash and cement kiln dust, treated auto shredder waste, construction and demolition waste, contaminated sediment sludge and shredded tires for ADC.
There are no current CIWMB restrictions on landfilling with green waste or using it as ADC, but regulations are in place to reduce landfill organics by 50 percent by 2020. Landfill operators in California are only supposed to apply an appropriate amount of green waste at the end of the day to cover garbage on the working face of the landfill. Thickness requirements are aimed at reducing the abuse of green waste as ADC.
Because green waste has high carbon value, the last place it should go is into landfills. Composting green waste offers the benefits of resource efficiency by creating useful, natural fertilizers and soil improvement characteristics. High quality compost is in high demand by farmers because of growing consumer demand for organic foods – people who want to avoid ingesting foods treated with chemical fertilizers and prevent the runoff of destructive chemicals from farmlands into the water supply.
But there are emerging national problems associated with large-scale municipal composting. In California, the apparent worldwide leader in implementing environmental regulations, we may be seeing the forerunners of composting regulations to come in other states. “Composting is starting to be regulated by our Air Resources Board because of the smell and by the Water Board due to concerns over ground water contamination,” said compost information specialist Charlene Graham at CIWMB. In addition, air quality regulators such as the South Coast Air Quality Management District and the San Joaquin air district have rules that require the reduction of volatile organic compounds and ammonia which are typically emitted from composting operations. ...read more