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Vol. 1, No. 1

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GOMCME LogoGulf of Maine Council on the Marine

Solar Aquatics: Greening up sewage treatment

BEAR RIVER, Nova Scotia -- A decidedly unglamorous part of the infrastructure in most communities, sewage treatment has attained star quality here.

Bear River's two-year-old Solar Aquatictm treatment plant last November received one of 15 international awards for excellence in environmental protection and enhancement from the Waterfront Center in Washington, DC.

The non-profit education corporation focuses on inland and coastal urban waterfront issues.

In 1995, the Bear River plant also received a Visionary Award from the Gulf of Maine Council on the Marine Environment, and was recognized at the G-7 summit in Halifax.

Designed as a greenhouse and built in Bear River's downtown area, the facility's aesthetic appeal and environmental approach have made it a tourist attraction and educational showcase, helping revitalize the waterfront, and drawing worldwide attention, said Annapolis County Councillor Bob Johnstone.

But celebrity aside, the plant meets the community's very down-to-earth need to collect and treat the sewage generated by its residents.

Applied Environmental Systems [AES], the Halifax firm that oversaw construction of the plant, acquired the license to the Solar Aquatic process for Eastern Canada from Ecological Engineering Associates [EEA] of Marion, Massachusetts.

Process treats to drinking water quality

Traditionally, treatment of sewage and wastewater is described in terms of three levels. Primary treatment uses settling and screening methods to remove solids. Secondary treatment uses an aeration process to add oxygen into the sewage to speed decomposition. Tertiary treatment removes higher levels of organic and solid materials, nitrogen, and phosphorous from the wastewater and disinfects it. Tertiary treatment brings the effluent to drinking water standards.

Paul Klaamas, an environmental engineer in Environment Canada's [EC] Environmental Protection Branch, said sewage treatment facilities on property owned by the Canadian Government must treat to the secondary level, but in other cases, "It's up to the provinces."

In New Brunswick and Nova Scotia, most sewage is treated to the primary or secondary level, then discharged into water bodies, said Al Smith, head of the Regional Habitat Program for EC's Canadian Wildlife Service, Atlantic Region. But currently, "There is no treatment whatsoever for the city of Dartmouth/Halifax," he acknowledged.

In the United States, the federal Clean Water Act requires that sewage discharged into water bodies be treated to the secondary level, said Carol Kilbride, spokeswoman for the US Environmental Protection Agency's [EPA] Center for Environmental Industry and Technology in Boston.

Greenhouse approach affordable, appealing

According to AES, the Solar Aquatic method can treat wastewater to tertiary quality levels cheaper than traditional methods, without chemicals, and producing less residual sludge.

The wastewater collected at the Bear River plant is funneled through the plant's greenhouse, which contains a system of solar tanks, a solar pond, and a constructed marsh designed to duplicate a natural ecosystem.

Plants, microorganisms, snails, and fish that live there consume most of the organic nutrients contained in the waste. The small amount of sludge generated by the process is composted on site.

"The place is filled with racked vegetation growing in this sewage," said Andrews. "You don't think you're inside a treatment plant."

The Solar Aquatic method can efficiently treat sewage flows of 20,000 to 100,000,000 gallons [approximately 74,000 liters to 38.5 million liters] per day -- the amount generated by an average small community -- according to AES, which also notes that the Solar Aquatic process appears more able than traditional sewage treatment methods to handle large amounts of toxic substances.

The method uses a large number of diverse organisms that can act as backups should one type of "friendly bacteria" be killed by a toxic substance.

System may expand to neighboring county

Serving 63 homes on the Annapolis County side of the river, the plant could begin to serve an additional 35 homes on the river's Digby County side this spring under a proposal to extend the system's main collection line, Johnstone said.

Previously, raw sewage from the village's homes and businesses was dumped directly into the river, and groundwater contamination from leaky septic systems was spreading among the town's small lots.

But the county couldn't afford conventional sewage treatment options, said Johnstone. Construction of a lagoon to hold the wastewater alone would have cost about $1 million, aside from piping costs and the cost of building a plant to treat the collected sewage, he said.

The Solar Aquatic facility cost approximately $600,000, including installation of a system of pipes to collect the wastewater.

Not only is the Bear River plant working, but so is another, much larger facility constructed in Beaverbank on the site of a nursing home complex, Andrews said.

Method addresses coastal water quality

According to Susan Peterson, president of EEA, which owns the rights to the Solar Aquatic technology, since the company was established in 1988, it has built 15 plants in the US, Canada, and Mexico that use the process to treat sewage, food processing waste, septic waste, and leachate -- the liquid runoff from landfills.

According to Peterson, enormous population growth since the 1970s has strained water resources and coastal environments in small towns, leading to "measurable coastal quality degradation." EEA's Solar Aquatics offer a more affordable, appealing method to address this issue, she said.

Kilbride agreed that coastal water quality in the Gulf of Maine has suffered. "Septic systems are a major problem along all of our coastal area," and faulty inland systems can cause groundwater problems that carry contamination to coastal waters as well, she said.