An American company is about to begin construction of a US$12 million anaerobic digester in Richmond, Canada that it claims will be North America's first high-efficiency system to produce renewable energy from food and yard waste.

Harvest Power's digester technology, if successful in Richmond, could be deployed at landfills across Canada according to Natural Resources Canada, which is investing $4 million into the company’s Richmond facility over two years.

The company is breaking ground on its digester, which will sit directly adjacent to the composting facility, within a month, according to Paul Sellew, Harvest's co-founder and CEO.

Sellew said the company chose Richmond because of federal and provincial government policies supporting renewable energy production. It also liked Metro Vancouver’s landfill diversion policies.

Although some Metro Vancouver municipalities divert more waste from the landfill than others, they are all participating in the Zero Waste Challenge, which aims to divert 70% of the region's solid waste from landfills by 2015.

Most of the 200,000 tonnes of food and yard waste that Fraser Richmond, a Canadian company acquired by Harvest Power in 2009, turns into fertilizer each year comes from Metro Vancouver.

In an email, the City of Vancouver's engineering department said 20,000 tonnes of yard trimmings and food scraps were collected from Vancouver homes from May to December 2010 – an 8% (1,500-tonne) increase compared with the same period in 2009.

Sellew said that in the U.S., about 97% of food waste is incinerated or taken to landfills.

"So places like Vancouver that are beginning this source separation of organics, those are the exceptions to the rule right now."

Sellew added that only about 100 communities in North America are separating organic garbage from the main waste stream.

Waste that enters the digester becomes a meal for microbes in an oxygen-free environment. A byproduct of the process is biomethane, or biogas, which can be converted into electricity.

Wastewater treatment plants and other facilities gasify liquid waste through digesters, but Sellew said Harvest's will be the first North American-based digester to gasify "high-solids" (food and yard waste).

Harvest's digester requires the high-calorie content of food waste to create usable biogas.

Give the imbalanced ratio of yard to food waste delivered to Fraser Richmond, only about 27,000 of the facility's 200,000 tonnes of collected waste will initially enter the digester annually.

The City of Vancouver says that approximately 35% of household garbage is compostable food scraps and food-soiled paper.

As more residences and businesses divert their food waste, Harvest will expand the digester's capacity from two to around five megawatts (MW) of biogas-generated electricity. Roughly 250 to 300 homes can be powered by one MW.

Once the waste is converted to biogas, its leftovers are composted with other garbage.

Sellew said the waste is largely the same volume and quality before and after it's digested.

The company is negotiating with local electricity companies about selling its biogas.

(Source: Food waste helping feed Harvest Power’s garbage-to-gold ambitions [Business in Vancouver])