Port Hawkesbury Paper is turning to a small army of micro-organisms to treat its excess water.

The paper mill is using microbes to treat 30,000 cubic metres of sludge every day. The innovative technology is being used in pulp mills across North America.

Port Hawkesbury paper produces 360,000 metric tonnes of paper a year, producing a lot of waste water, known as effluent.

The plant is taking that effluent and introducing millions of micro-organisms to it in large containers called reactors. The microbes are then known as "activated sludge."

Port Hawkesbury Paper environmental specialist Ken Mitchell says the microbes need to be kept at specific temperatures and daily tests are performed to ensure the multistep process is working as it should.

“The micro-organisms, on a biological level, actually consume the chemicals in the effluent and convert it into materials more natural to the environment,” he says.

Makes waste water benign

Port Hawkesbury Paper Pulp Production Manager Mark Frith explains the process that takes place in the reactors.

“By taking time in the reactors with nutrients — and we have nitrogen and phosphorus present, and all the oxygen which is mixing in — the biology and the biosolids make the waste water completely benign to the receiving water behind us,” he said.

There are many stages to the process, from siphoning off water to separating the water from solids. Tonnes of micro-organisms then eat through the sludge.

Firth says when the biology works well, it separates the solids out perfectly and ensures that only a clear liquid runs off into the Strait of Canso.

The only evidence of the now-treated effluent is a white frothy patch in the waters adjacent to the plant.