We need to rethink our traditional actions as we endeavour to tackle the municipal solid waste problem while managing the myriad of other environmental risks society faces, such as climate change. Given the reality we all generate waste and the fact that methane escaping from the landfilling of this waste is the third largest man-made contributor to GHGs makes it a global, societal responsibility to be more intelligent about waste management.
One exciting opportunity that has the potential to become a pillar in the North American solution is to convert the organic fraction of municipal solid waste into clean renewable energy. So there’s no confusion with other waste management practices, we will refer to this type of renewable energy as “bioenergy.” This opportunity is centred on the proven biological process of anaerobic digestion (AD). AD is deployed in thousands of organic processing facilities outside North America and in wastewater treatment plants around the globe.
Two cities in North America are leading the charge into this relatively
August/September 2008 www.solidwastemag.com31 new and burgeoning AD frontier. In Toronto, the six-year-old green bin source-separated organics program requires over 500,000 single family homes and thousands of businesses to separate over 100,000 tpy of their food/household organics, including disposable diapers and pet wastes, for weekly curbside collection. (See article, page 47.) In 2009 this program will be extended to over 500,000 multi-unit homes.
In September 2002, the city opened a 25,000 metric tpy AD organics processing facility utilizing the BTAprocess. Today it remains the cornerstone of the processing capacity supporting the program and the throughput has now improved to over 35,000 metric tpy. The lessons learned and success of the project has led to a formal procurement process that began this spring. The plan is for two AD facilities to be located on city-owned transfer station sites to annually convert 110,000 metric tonnes of SSO into bioenergy and high quality soil amendments.
In San Francisco, a very similar management practice is taking shape.
San Francisco waste staff discovered more about the bioenergy opportunity from their Toronto peers and used their learning to help develop and implement a similar program. Working with their service provider, Norcal Waste Systems (Norcal) and the East Bay Municipal Utility District (EBMUD), the plan is to implement an SSO collection and processing solution to annually convert 38,000 tons of SSO into bioenergy and a variety of other beneficial use organic products. Norcal will collect the SSO and then pre-process it utilizing the BTAprocess. Using excess capacity, EBMUD will then digest the resulting material and send the biogas to an existing cogeneration facility to produce renewable bioenergy. The processing solution is being delivered through a partnership between Metcalf & Eddy (an AECOM Company) and Canada Composting Inc. (CCI).
CCI is a pioneer in the development of commercial bioenergy solutions in North America. The company developed North America’s first two commercial, large-scale AD plants and has been engaged in numerous AD projects and studies in Canada, the USA and the Caribbean. Using a partnership approach, the corporate mission is to design, build, own, sell, finance and operate, in any combination, processing solutions that recover the resources inherent in the organic fraction of waste. The corporate vision is to use this fraction to produce clean, renewable bioenergy and a variety of organic products in an environmentally beneficial manner.
The nucleus of CCI’s bioenergy solutions is the BTAprocess (see boxed item). This German-developed, closed loop technology integrates sophisticated wet pre-processing techniques followed by AD. Acceptable residential and commercial generated waste feedstocks cover a broad range, including all pre-and post-consumer food scraps, non-recyclable fibre, disposable diapers, pet wastes, liquids, food processing residues, slurries, filter cakes, and compound packaging. A central tenet in the flexible, modular and robust process design is to strive for the diversion and best reuse of all the process outputs, including any residuals.
For those waste management practitioners that see a fit with their strategic solid waste plans and local environmental management plans and choose the bioenergy direction, the benefits to be accrued will translate into three primary value points for their communities:
1. Maximized diversion and reuse of organic waste resources;
2. Maximized reduction of local, waste-related GHG and VOC emissions, and;
3. A secure, community-based source of renewable bioenergy. It’s not about managing solid waste, its about changing and elevating our thinking.
Randy Cluff is Director, Business Development, with Canada Composting Inc., in Newmarket, Ontario. Contact Randy at email@example.com