Solid Waste & Recycling

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Composting in Saskatchewan

Quickly dispelling any eastern notions I might, have Joan Harrison of the Saskatchewan Waste Reduction Council (SWRC) succinctly states, "It's not all flat and its not all Prairie" -- the "it" being S...


Quickly dispelling any eastern notions I might, have Joan Harrison of the Saskatchewan Waste Reduction Council (SWRC) succinctly states, “It’s not all flat and its not all Prairie” — the “it” being Saskatchewan.

Like the province itself, the composting activities are wide and varied, if not a bit off the beaten track.

Until the 1990s the level of composting activity in Saskatchewan was quite low. Through the diligent work of the SWRC and dedicated individuals, composting has begun to make some modest inroads into the collective consciousness and in practice. (The SWRC has built up a good base of composting information on its websitewww.saskwastereduction.ca/ composting/index.html)

The main driver slowing the development of centralized composting programs for residential waste is the low tipping fee at landfills.

A few examples of composting initiatives follow.

City of Swift Current

In south-western Saskatchewan lies Swift Current. The city of 16,000 has promoted backyard composting and vermicomposting, through education and advertising, to its residents for a number of years. As well, it has provided curbside pickup of leaf and yard wastes since 2001.

Residents place materials, including grass clippings, weeds, plant stalks and tree leaves, in clear plastic bags. Collection is offered every two weeks from mid-April to early November by their private waste hauler Waste Management Inc. It’s estimated that 1,000 tonnes of waste is collected each year.

Composting is undertaken by Delta Rock and Sand. The incoming leaf-and-yard waste is manually debagged by workers organized through the Salvation Army. It’s mixed with cattle manure and straw bedding and formed into outdoor windrows. A high quality product is produced and sold for $19.50 per cubic yard or $3.50 per 5-gallon pail.

Prince Albert

The City of Prince Albert upgraded its wastewater treatment plant in the summer of 1999 from primary to secondary treatment using the conventional activated sludge process. The treatment processes incorporated at the J.W. Oliver Wastewater Treatment Plant generate biosolids as a by-product. These biosolids consist of primary and secondary waste activated sludge. The biosolids are thickened and dewatered at the plant prior to transport to the composting site, located at the municipal landfill, for stabilization and storage.

Working with EarthTech Canada, they developed an aerated static pile composting facility enclosed in a building for year-round operation. The composting facility, which opened in 2003, was built with financial assistance from the Canada-Saskatchewan Infrastructure Program at a cost of $2.2 million. It handles approximately 8,000 cubic metres of dewatered sludge annually.

After delivery to the site, biosolids are mixed with wood fibre and chips to balance the carbon to nitrogen ratio, control the temperature and to improve porosity and structure. The sludge/amendment/recycle ratio-mix design is 1: 2.4: 0.6. Three days worth of the mixed feedstock is placed in one of six bunkers using a front-end loader and allowed to compost for 18 days. Pathogen reducing temperatures greater than 55 degrees Celsius are reached for several days. Compost is cured outside in windrows for several months. The wood chips are removed from the mature compost by trommel screening for reuse in the compost mix.

Up until 2004, the finished screened compost was used as part of the final cover in the landfill decommissioning project. Since then, Saskatchewan Environment has given them approval to cover the existing landfill solid waste with stockpiled compost or mix the screened compost with topsoil for use by the Community Services Dept. in civic land- scaping.

Old zoo, new trick

Saskatoon’s Forestry Farm Park is a national historic site originally established in 1913 to grow and distribute tree seedlings for farm shelter belts. A zoo was established there in 1972. The zoo and park began accumulating animal manures and plant materials many years ago in static piles but there was no active composting. A compost project was initiated in the late 1990s when Larry Mullen, a local market gardener, asked to buy some of the older decayed material. After discussion, Larry was hired onto the park staff with the compost initiative as part of his job and the “Zoo Poo” project was begun.

The zoo now has an ongoing program to compost non-carnivore animal wastes and bedding mixed with plant materials from that park, as well as other nearby city parks. The materials are mixed and arranged in outdoor windrows and turned with front-end loaders. Temperature is monitored.

A portion of the finished compost is screened, bagged and sold to raise money for zoo projects. A 12 kg bag sells for five dollars. In 2005, $2,500 was raised and was directed towards a butterfly house in one of the onsite greenhouses. The remainder is used by the Parks Department. The city would like to expand its “in-house” park department composting but needs to find another location as the zoo site can’t handle more material.

Dead heads

Animals that die in livestock operations are a major management issue in Saskatchewan. Until recent changes in regulation it was common practice to take “deads” to a rendering plant.

Animal mortalities are typically composed outdoors in large bins made of wood or bales. The dead animals are composted with straw or sawdust. For the initial phase, the pile is left undisturbed. When the internal temperature drops, the pile can be turned. The composting process degrades all but the most resistant parts, such as teeth.

Composting dead poultry has been a common practice for some time. The technique is now frequently used by hog producers. Much larger animals such as cows can also be safely handled in this way. Most disease-causing organisms are reliably destroyed by the composting process. There are indications that the composting process does not destroy the prions that are associated with BSE. However, removing “deads” from rendering operations does much to remove possible infected animals from the food chain (i.e., animal-to-animal transmission).

Saskatchewan Agriculture has published an excellent booklet called Composting Animal Mortalities: A Producer’s Guide (www.agr/gov.sk.ca Go to the website and choose livestock, then beef, then production information).

Conclusions

The development of composting continues to proceed slowly. It’s still infused with significant grass roots involvement of those that want to do the right thing, but is moving towards centralized composting to meet specific needs.

As Harrison indicates, “Composting is not a priority but other waste issues have received more attention. There are good stewardship programs for used oil collection and old tires. New stewardship programs for paint and electronics are about to begin. The province is involved in developing a new solid waste strategy which is part of a larger ‘green’ strategy.”

Proving that Saskatchewan is not easy to pigeon-hole, Harrison concludes: “Saskatchewan is easy to draw … but difficult to spell.”

Paul van der Werf is president of 2cg Inc. in London, Ontario. Contact Paul at www.2cg.ca. With files from Joan Harrison, SWRC.


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