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Regional municipality looking for alternative to treat septic tank waste starting next year
By Dave Rogers, The Ottawa Citizen
OTTAWA-Outaouais sewage lagoons condemned by Ottawa Riverkeeper Meredith Brown as likely to pollute the Gatineau and Ottawa rivers are already being used in three West Quebec municipalities with provincial government approval.
Brown said Monday that the liquid flowing from the sewage lagoon that the MRC des Collines plans to build near the Gatineau River to treat septic tank sludge would probably not meet proposed federal standards for river water.
The regional municipality is considering a sewage lagoon because the City of Gatineau has decided to stop treating septic tank waste from the Gatineau Hills and the Pontiac at the end of 2010, leaving more than 45,000 rural Outaouais residents without sewage treatment.
Patrick Laliberté, environment and physical resources manager for the MRC des Collines, said the sewage lagoons in Chelsea, Cantley and Notre-Dame-de-la-Salette already worked well by treating sewage with bacteria. He said septic tank waste was more concentrated, but could be treated effectively in the same way.
Laliberté said the region would pump 2,000 tonnes of sludge yearly from septic tanks for treatment in a sewage lagoon. Solids that settle in the lagoon would be composted and used as fertilizer or burned to produce electricity. The liquid would flow into the Gatineau River.
The MRC des Collines has not chosen a site for the lagoon, which is to be completed by December 2011.
Brown warned that sewage sludge pumped from septic tanks was a threat to drinking water and called sewage lagoons a rudimentary form of sewage treatment.
“The effluent from the lagoon has to be treated because it is really concentrated and actually gets dumped into the river,” she said. “It is well known that the effluent from lagoons won’t meet federal standards.
“Lagoons have trouble meeting nitrogen, ammonia and phosphorus standards in the aquatic environment. Phosphorus causes blue-green algae blooms and ammonia is toxic to aquatic life.”
Brown said the system of treating sewage in Old Chelsea using cattails and aerated water and a new sewage lagoon scheduled to open in Farm Point in August would add nutrients and toxic chemicals to the Gatineau River.
“There are tried, tested and true designs where you don’t have to release liquid effluent into a lake or a river,” she said. “If you have a lot of area you can slowly release it into the ground and have a lot of evaporation.
“The MRC des Collines should be looking at a solution that meets all its needs and protects the river at all costs.
“They should investigate other alternatives to treat septic waste.”
Alain Bourgeois, Chelsea’s director of public works and infrastructure, said a reed bed sewage system on Mill Road that handled waste from 60 households treated contaminants effectively.