Wastewater effluent is the biggest cause of water pollution Canada. But when sewage sludge is properly treated, it can be a source of nutrient-rich organic materials that can be converted in fertilizer or a source of renewable energy. Here are interesting sewage treatment and biosolids management trends around Canada.
Ontario Develops Thermal Hydrolysis Digester
Thermal hydrolysis is a game changer in sewage treatment. This method employs steam injection to disintegrate cell structures freeing up organic compounds and lessening the viscosity of the sludge. The sludge is exposed to high temperatures and undergoes pressure cooking then quickly decompressed prior to anaerobic digestion. The result is more digestible organic matter to feed the micro-organisms in the digester. The process also kills pathogens and decreases foul odours.
A company based in Cambridge, Ontario by the name of Lystek International focuses on providing thermal hydrolysis solutions for biosolid management. The company has developed the first commercially available, low temperature, low pressure mobile Thermal Hydrolysis Processing unit: Lystek Mobile THP®.
The Lystek Mobile THP® offers smaller wastewater treatment plants a cost effective alternative biosolid management technology. To date, this is the smallest equipment available in the market. It is placed in two vertically stacked 50’ containers and requires minimal, external utilities. Another added advantage is biogas production that supports the green energy initiatives of the province.
British Columbia Wastewater Treatment Plant Recovers Usable Energy
Vancouver has created a sewage treatment process that is considered the largest heat recovery system in the province of British Columbia. The $700 million North Shore Wastewater Treatment Plant (NSWWTP) will generate heat from the treatment process by collecting heat from treated sludge which averages 15 degrees Celsius. Treated wastewater goes through a heat pump and the condensed heat from the pump will raise water temperature to up to 82 degrees Celsius.
The heated water is then utilized to heat buildings while the used up hot water is brought back to the heat pump that is again reheated to the desired temperature. The distribution system will be operated and managed by The Lonsdale Energy Corporation (LEC). The treatment plant will allocate about 5 megawatts of heat through a kilometer-long heat distribution piping developed by the said company. The recovery system is estimated to reduce greenhouse emissions of the North Shore Wastewater Treatment Plant by 75%. For every unit of electricity used up, the system can generate three units of heat. LEC only needs 5 megawatts of heat from the effluent to generate 25 megawatts, making it one of the largest heat recovery systems in British Columbia.
British Columbia Company Mixes Biosolids W/ Hog Fuel and Wood Ash
To meet the local government standards set the province of British Columbia on composts, the cities of Kelowna and Vernon have developed an organic fertilizer that mixes biosolids, hog fuel, and woodchips and ash. The woodchips and ash help mitigate the odours by delaying decomposition making it more acceptable to end-users and the community.
Sold as OgoGrow, it increases the available nutrients in the soil and improves its ability to absorb water. OgoGrow is a Class A type of compost that can be safely applied to flowers, shrubs and vegetable gardens making it popular with gardeners and landscaping companies. It can also be used to improve soil in golf courses and other green spaces. The company produces around 30,000 – 50,000 yards per year netting around $500,000 in sales per year.
Prince Edward Island Uses Biosolids as Topsoil for Green Spaces
While most biosolids based organic fertilizers are used by the city of Summerside in Prince Edward Island (P.E.I.) to boost agricultural uses, it has also started to use biosolid management to boost topsoil in various city parks and green spaces.
To ensure that the biosolids are safe for use, they go through several stages of processing observing strict standards set the both the municipal and federal governments. The City Director of Community Services J.P. Desrosiers noted that there was marked improvement in the health of greenery in public spaces. The residents are made aware of the program and expressed their support for the using biosolids to enhance topsoil. While treated biosolids does not pose any harm to humans and the environment, as an extra precaution, neighbourhoods are notified when biosolids are applied on the fields to limit exposure. They are also informed beforehand when heavy rainfall is expected, which may release strong odours in the air. The local government continue to work with the community to keep them updated on the initiative.
If you are a municipality in Ontario and in need of a biosolids management solution, please feel free to contact us on 1 (877) 479-1388.