Add a rinsate biobed
Originally published March 2020 in Farming Smarter magazine
by Kristi Cox
Biobeds are a low cost, simple way to responsibly handle pesticide rinsates and maintain healthy water and soil. Farming Smarter installed one and they’re making it easier for others to have one too.
Using biobeds contains the rinsate left when changing products or putting a sprayer away. While rinsate is mostly water, it still has herbicides, fungicides or insecticides in it. Typically, producers have a dedicated spot to spray this waste.
“The advantage of using a pesticide rinsate biobed is that it doesn’t take more space than a dedicated area and you know where your rinsate is because it’s collected and contained,” explained Dr. Claudia Sheedy, Research Scientist in Environmental Chemistry and Immunochemistry with Agriculture and Agri-Food Canada. “You can control what happens to it.”
Sheedy explained that if rinsate is sprayed on the land, the residues can travel to groundwater or nearby surface water and contaminate the environment.
Biobed systems include a collection pad that drains into a sump, a holding tank and two biobed tanks. The biobed tanks have gravel, a sump pump, filter fabric, and heat tape. They also have a bio-mixture, consisting of topsoil, wood chips or straw, and peat or compost.
The liquid drips slowly from the holding tank into the first biobed tank so the system doesn’t get saturated. It percolates through the first tank and it moves into the second tank.
“Once it comes out of the second tank it’s clean enough water to use for grass or shelter belts,” said Jamie Puchinger, Farming Smarter’s Assistant Manager.
The two biobed tanks are seeded. The chemical concentration is strong in the first one, so there usually isn’t any growth, but there should be plant growth on the second tank.
“It’s a good indication that the biobeds are working as expected,” said Puchinger. “You start to see some death on the second biobed if the first isn’t quite doing it’s job. It’s a visual gauge of how well the system is working.”
Sheedy explained that biobeds have been tested with about 200 pesticides out of the approximately 600 active ingredients registered for use in Canada.
“For these 200 pesticides, the vast majority of them are removed 100% by the biobed,” Dr. Sheedy said. “We’re not sure if they’re being degraded by the microbes inside the bio-mixture or if they’re simply being retained by the bio-mixture itself, but they’re not found in the final effluent after the rinsate has gone through the biobed.”
Farming Smarter secured funding through the Canadian Agricultural Partnership for a biobed project. That project has two purposes. The first is to ensure that Farming Smarter takes care of all its rinsate responsibly. The second is to encourage on-farm adoption by producers in Alberta.
“Our goal is to have 50 farms in Alberta implement a biobed in the next couple of years,” said Puchinger.
To aid in this goal, Farming Smarter is building a demonstration system on a mobile trailer. It has the same components as a full system, but at a smaller scale. Producer can borrow this trailer and Farming Smarter can take it to events throughout the province to spread awareness.
In addition, Farming Smarter worked with Southern Irrigation to create a kit that will allow producers to easily build a system.
“We’ve taken all the guess work out of it at this point,” said Puchinger. “It creates an easy to follow system, so you don’t have to make multiple part runs.”
The Biobed kit costs less than $5000, and producers can apply for Canadian Agriculture Partnership funding to cover part of those expenses. This makes it a simple, low cost solution to managing rinsate. After construction, biobeds are relatively low maintenance. They need to be winterized in the fall. This process for producers includes capping the biobeds with a lid or tarp to prevent the bio-mix blowing in the wind; dismantling the pumps to prevent freezing; draining all lines of fluids.
The bio-mixture eventually needs replacement, but Sheedy is still studying its useful life span in Canada.
“In Europe, they typically tell growers to remove it after seven years, you compost it for a year, and you replace that bio-mixture with fresh bio-mixture into the tanks,” said Dr. Sheedy.
Dr. Sheedy is now past the eight-year mark in research to determine how long the bio-mix will last in Western Canada.
“We think we could probably go up to ten years,” explained Dr. Sheedy. “The reason for this is we have pretty harsh winters and there’s no agriculture conducted over the winter. The biobeds get a rest. One of the factors in biobed aging is the organic matter degrades over time, so that’s probably what the limiting factor in terms of 7-10 years.”
She explained that the physical structure of the biobeds will last much longer. It’s just the bio-mix that has this shorter lifespan.
Currently, most of the biobeds in Canada are demonstration biobeds at Agriculture and Agri-Food Canada research stations, but municipalities are getting on board.
“The municipality of Grand Prairie has a biobed they use for a herbicide road maintenance program, and the City of Saskatoon has a biobed now, so the interest is there,” said Dr. Sheedy.
“We want to encourage farmers to pick up the practice,” said Puchinger. “It’s a relatively inexpensive way to dispose of waste and it’s also a good news story. We ensure that we take care of our water and that we maintain soil resources for future generations by using this method. It’s a fairly simple fix, the science is there, and it’s proven to work so let’s get it done.”
Follow Farming Smarter’s Biobed project