Herbicide waste collected, then eaten by mould

Machinery is cleaned at the wash station and water goes from the collection pad to the bio bed.  |  Mary MacArthur photo

Bio bed is designed to collect chemicals in a holding tank 
where a mixture of peat moss, soil and straw break them down

GRANDE PRAIRIE, Alta. — Sonya Raven wants to help farmers get rid of their dirty little secret: what to do with the water after rinsing pesticides from the sprayer?

“I come from a ranch and know many, many farmers that have that spot behind the barn that shall remain unknown and untalked about,” said Raven, the agricultural fieldman for the County of Grande Prairie.

“We’re not talking intense concentration of herbicide, but it’s still not appropriate in my mind.”

Farmers aren’t intentionally trying to harm the environment, but they don’t know what to do with the rinse water with traces of herbicide. Do they spray it in the ditch, on gravel, on bare ground?

The problem also plagues chemical companies, custom sprayer operators and municipalities and counties.

When Raven heard a discussion on herbicide bio beds two years ago, she wanted to put the theory to practice and show farmers and other counties that bio beds are a simple yet effective solution to dealing with pesticides rinsed out of sprayers.

“For us, this is a way for us to take that spot behind the barn, bring it out into the open and do this.”

A bio bed is a lined herbicide disposal area that collects the rinse water on a collection pad where it drains into a holding tank and is then pumped onto a bio bed made from a mixture of soil, peat and straw to create a white mould that eats the herbicide.

“For me I just think it is important we are as environmentally conscious and responsible as possible as we can be,” said Raven, who built a bio bed at the County of Grande Prairie to dispose of its chemicals.

“It’s not terribly expensive and will last years.… It worked like a hot darn last year.”

Herbicide bio beds are still in the research phase in Canada, and Agriculture Canada researchers are testing different designs. However, they have become common in Europe.

At the County of Grande Prairie site, the sprayer equipment is driven on a mat where it is washed and any residual herbicide sprayed out and drained into a collection pit.

The wash pad is edged with children’s pool noodles to prove the system could be built inexpensively.

“I love the pool noodles around the wash bed. It’s simple and you can build it as big or as small as you need it,” said Raven.

The rinse solution is collected in an underground catchment basement and pumped onto the plastic lined bio bed. The soil and organic matter bind the herbicide particles, and the straw is the host for the white mould colony.

It’s estimated that 2,4-D breaks down in 10 to 12 weeks naturally, but takes only two weeks to break down in a bio bed.

“We wanted to have something that was a solution to us but also to show others that it is not cost prohibitive and it can be done,” said Raven.

“I am determined to prove we are environmentally conscious, because we are. To me it was such an easy win. It is very important as municipalities that we lead the way and show people that there are other options.”

About the author

Mary MacArthur's recent articles


Stories from our other publications