New tech helps prevent surface water contamination

Bayer's Phytobac system is a self-contained, closed system that captures wastewater and degrades pesticide residue through a biobed substrate of straw and soil

In recent years, the protection of water resources has become an increasingly important issue around the globe. Of particular concern for farmers is potential contamination of surface water from crop protection products, especially when cleaning out the spray tank. Bayer’s new Phytobac system offers a solution.

“Bayer developed this system in Europe, where dense population and small farms situated close to waterways made concerns over surface water contamination an issue that needed to be addressed,” says Lee Huber, residue lead, environmental affairs with Bayer.

“We worked with local growers and Beutech, our manufacturing partner in the Netherlands, to develop the Phytobac system, which helps address the needs of the local population,” says Huber. “Although the Phytobac system was initially developed for smaller farms, it is fully adaptable to any size of farm.”

It’s common practice for growers to clean out their spray tanks and containers in their yards. If not addressed properly, the wastewater from cleaning the sprayer has the potential to runoff into ditches or other bodies of water leaving pesticide residue behind.

Some growers already filter the wastewater through beds of straw and soil (a biobed) in order to replicate natural microbial breakdown in the field. However, in these makeshift systems, the amount of water is never controlled, meaning the biobed could easily become oversaturated or too dry and the breakdown of pesticide residue isn’t guaranteed, explains Huber.

In the Phytobac system, wastewater is stored in a buffer tank and then dripped evenly over a biobed substrate of soil and straw. Irrigation timing is controlled and activated by soil moisture probes, allowing for optimal soil conditions for degradation of the residue. A roof above the biobed prevents rainwater from entering the system.

The straw in the Phytobac is added at least once, usually at the beginning of each year, and has to be turned at regular intervals. The straw maintains optimal levels for microbial degradation, facilitates the growth of microbial strains and works as an energy source for microorganisms. All the fungi and bacteria are naturally occurring with no other foreign organisms added to the system. These micro-organisms work to break down the pesticide residue that enters the system.

The first Phytobac in Canada was set up in 2015 at Bayer’s research farm just outside of Rosthern, SK.

A second Phytobac was established at Ennotville, ON, and there are plans to develop a third system on the Canadian prairies in the near future.

So far, the response to the Phytobac system has been very positive, says Huber.

Phytobac system

1. The washing plate collects the rinse water from spray equipment and drains it into a contained buffer tank.
2. The holding tank holds water until water sensors indicate the system is ready to receive more moisture.
3. A control unit determines soil moisture and the amount of water to apply through drip irritation.
4. A drip irrigation setup applies wastewater to the Phytobac system.
5. A biobed substrate of soil and straw degrades the pesticide residue.
6. A two-way switch lets operators send clean water to the holding tank or rinse water to the buffer tank.

Bayer will continue to operate these Phytobac systems and monitor their performance in the Canadian climate.  “Initially we wanted to see if this system could withstand a harsh Canadian winter,” says Huber. “We knew it would be turned off over the winter months, but we wanted to make sure it would continue to work in the spring. We pull out the controls in the fall and install it in the spring and it has performed very well year-over-year.”

The Phytobac system has become popular in Europe, with more than 3,000 units currently installed on farms. Several European governments have offered subsidies to growers in order to encourage them to set up this system on their farms, as it’s proven to be an effective wastewater management tool.

“There are many benefits for the environment and farmer,” says Huber. “This system helps degrade spray tank residue with naturally occurring microbial species reducing contamination of surface and/or ground waters. It demonstrates Bayer’s commitment to sustainable agriculture and social responsibilities, and is a representation of modern agriculture moving forward in a sustainable way.”