Safely managing milkhouse waste

by Christine Black

airy farmers can start washing their hands of milkhouse wastewater, thanks to research that is making disposal safer than ever before.

Ian Malcolm and William Kollaard, engineering researchers at Collège d'Alfred, have found a way to clean up milkhouse waste in Canada's dairy industry.

They've spent four years researching, developing, and testing various methods to deal with milkhouse washwater. As a result, they've come up with a small chemical reactor, called a "flocculator", that is making waves in milkhouse washwater disposal.

"The flocculator is a valuable innovation because the system can remove up to 99 per cent of the harmful phosphorus, as well as most of the milk residues left behind in wastewater," says Kollaard. "That makes the final disposal more reliable."

Milkhouse washwater has posed a problem in the dairy industry for years. To keep Canada's milk supply among the safest in the world, farmers wash their equipment and holding facilities after each milking. But this wash water is laden with phosphorus which can contaminate nearby surface waters. In addition, fat from milk residues clogs tile fields. Replacing clogged septic systems or manure storage capacity creates added expenses.

But with the Collège d'Alfred flocculator, things are looking up. The flocculator is the first chemical treatment system on the market and works by combining washwater and lime in a tank. An agitator mixes the contents of the tank, causing the phosphorus and fat particles to collide and bind to the lime (a process called flocculation).

Once the agitation stops, the bigger, heavier particles settle, allowing most of the original volume of washwater to be discharged phosphorus- and fat-free from the tank. The remaining sludge is then added to the existing manure system.

"The volume of washwater that has to be stored is dramatically reduced using the flocculator," says Kollaard. "Not only are the phosphorus and fat particles removed, but the remaining water can potentially be recycled."

Thirteen dairy farmers are housing individual units on site. With site testing done in Ontario, Quebec, New Brunswick, Nova Scotia, and New York state, the flocculator is now being marketed worldwide.

The flocculator requires a six-foot square space and will cost about $6,000 to install.

Preliminary research on the flocculator was sponsored by the Ontario Ministry of Environment and Energy, the Ontario Ministry of Agriculture, Food, and Rural Affairs, and the Dairy Farmers of Ontario. On site systems are funded by individual producers with the help from numerous conservation programs.