Sewage plan | The hamlet of Cynthia, Alta., builds a solar greenhouse to treat its sewage with plants and bacteria
CYNTHIA, Alta. — It’s a question facing hundreds of small hamlets and villages across the Prairies. What happens when the sewage lagoon needs replacing?
The councillors at Brazeau County in Alberta decided not to build another smelly lagoon at the edge of town. Instead, they built a solar greenhouse that treats the sewage with plants and bacteria.
County officials took a chance on new technology for the tiny hamlet of Cynthia, population 60, that they hoped could be a model for sewage lagoons across the country.
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Brazeau County reeve Wes Tweedle said it was an experiment. They had to do something with their existing sewer system and took a chance on the alternative technology.
The $1.8 million Solar Aquatic Systems plant works well when it is working and fails dramatically when it fails, said the county’s Darcy Mulroy.
“It’s wonderful when it’s working,” said Mulroy, who has been in charge of repairing the Cynthia facility since it was built in 2009.
The 2,000 sq. foot glass-fronted building looks more like a greenhouse than a waste water treatment plant. It is designed to clean 88 cubic metres of effluent a day.
Sewage from the hamlet is piped into a large 20 cubic metre surge tank and then into six aerobic and anaerobic tanks inside the facility.
Bacteria grow on the tank walls and on the roots of tropical plants floating in the water, which provides more surface area and increases the number of bacteria in the water.
“The more bacteria the better,” said Mulroy.
However, the new sewage plant has been plagued with problems from the beginning.
EcoTek, the company from Langley, B.C., that designed and built the plant, had built only two other plants, both in warm climates: British Columbia and Cuba.
Last fall, the aeration system and boiler needed replacing. The passive solar building faces west rather than south and gets too hot during winter days.
The solar panels were filled with water and stopped working after they froze. Recently the surge tank pipe separated and needed repair.
This spring, Mulroy’s biggest problem was trying to keep ground water out of the sewage lines.
Despite the problems, Mulroy still believes the system has its benefits. It was the sewage treatment facility that enticed Mulroy to start working in the county’s water and sewer department.
“This is definitely a viable option,” said Mulroy, who has led tours from other municipalities at the facility.
“I don’t want other people to deal with the same mistakes as we have.”
Tweedle said the system will be a good alternative for small towns and villages once the problems are ironed out. With no smell, the facility can be located inside a community.
“If we can get it working good, it is an excellent alternative,” he said.
The plant may need to be expanded because of new oilfield camps hooking up to Cynthia’s water and sewer system.
Mulroy believes an A-frame building with roof openings to regulate the heat would be an easy addition and help fix some of the light and heat issues.
The plant is designed to be a continuous flow system with sewage flowing in and clean water flowing out continually.
Alberta regulations require enough lagoon storage capacity for nine months. The sewage is pumped into the old lagoon once it is cleaned.
Twice a year, the clean water is pumped from the lagoon to a nearby waterway.
The lagoon was drained June 18 and the water quality was “phenomenal,” said Mulroy.
“You could see right through the water to the bottom when we were discharging. It was clean.”
