Compost Operations


Wastewater treatment byproducts, or biosolids, are used as a key ingredient in the GMWC composting system.

Treatment of sludge at the WWTF involves conditioning with liquid lime, use of high-speed centrifuges for dewatering, followed by the addition of dry lime.

Upon arrival at the Composting Facility, it is mixed with green waste consisting of bark (from sawmills), ground forestry waste, wood chips and other green waste.

The initial mix produces 42 tons windrows, on average annually, that are 50 m long on the composting pad. Windrows spend a minimum of eight weeks on the active aerated pad and are turned over twice. The windrows are covered with a breathable cover during the initial phases and can reach temperatures of more than 70° Celsius. The windrows are then moved and grouped into lots of three initial windrows on the curing pad where they are conditioned and left to compost at a slower rate while cooling down. The complete process takes one year. Consequently, one year's production will be available for use in the following year.

Processing and product usage in the present year involves screening of the previous year's stockpiles (lots) for use by the general public, landscapers and local municipalities. The public was allowed to pick up compost free of charge from the self-loading bins. Product was sold to landscapers and is provided to the area municipalities for their horticultural activities and various land improvement/development projects.

Historical Data :








    2016        2017       2018        2019   

                     Biosolids Wet-Tonnes





 11,311    11,128    11,183     11,188  

                     Biosolids Dry-Tonnes





   3,169      3,082       3,154       3,105  

                     % Solids





   28.0        27.7         28.2          27.8  


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