Municipal Options for Handling Compostable Materials

Unwanted food and yard materials make up to 60% of the household waste stream (by weight) in the warm months and account for a third of the yearly totals. Tackling such a large part of the waste stream has obvious appeal, but it has sometimes been overlooked as a first step in a waste reduction plan.

One big advantage is that these materials can be processed and used in the community, saving the need to find distant processors and pay for transport. Returning the nutrients in these materials to the soil builds fertility where it can be used and avoids the problems with methane, hydrogen sulfide and leachate that they can cause in landfills. Communities throughout Saskatchewan have recognized the potential of diverting these materials and are using a number of different strategies:

Keeping Compostables at Home — Helping citizens process compostables at home is the first choice of many municipalities—even large ones like Toronto and Calgary. People are encouraged to leave grass clippings on the lawn, use clippings and leaves as mulches and to compost food and plant materials in bins. Saskatoon, Regina, and many other Saskatchewan communities promote home composting. Lloydminster, Saskatoon and Unity subsidize bin purchases.

Community composting — Composting can be done at the apartment block or neighbourhood level. It is usually handled like a backyard site, with big piles or large capacity bins. The City Park Compost site in Saskatoon is one Saskatchewan example. The City of Toronto encourages apartment buildings, schools, and community gardens to consider this option and sells modestly priced, secure wooden bins to interested groups.

On Site, In-Vessel Composting — Large institutions can take charge of their own compostable wastes on site. They usually use sophisticated batch composters that let them speed up the early part of the composting process. The Regional Psychiatric Centre, Saskatoon, processes their food wastes mixed with wood chips in a Wright in-vessel compost system.

Yard Waste Composting — Some communities offer pick up or drop off points for yard materials which are then composted outdoors in long windrows. The level of management varies greatly at these sites; better compost is made when piles are well mixed, watered and turned. Outlook, Battleford and Humboldt compost yard waste in windrows and offer pick-up service to residents.

Co-Composting — When two different waste streams are mixed for processing, it is called co-composting. Mixing yard waste with manure, as happens at the Moose Jaw Exhibition compost site, is a common form of co-composting. The Edmonton co-composting facility mixes compostable home waste with sewage sludge.

(Source: WasteWatch, December 2000)

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