Worms Next Champions of Wastewater Management

Managing waste on dairies can be an expensive and daunting task for farmers who look to run profitable businesses while protecting the environment. That is why farmers are increasingly turning to technology to make this task more sustainable. Some technologies even make wastewater reusable.

One such technology comes from BioFiltro, an international wastewater filtration company that has made revolutionary advances in the liquid waste management field with the BIDA® System they pioneered in 1995 in Chile. The energy-efficient BIDA® System removes up to 99% of contaminants from wastewater in just 4 hours through a filtration process with worms doing most of the work. The filtration process is natural, chemical-free, and uses up to 95% less energy than traditional methods. This passive aerobic system converts wastewater into two valuable resources for agriculture: clean water which can be used for irrigation and worm castings, a nutritious and microbe rich fertilizer.

Austin Allred, owner of Royal Dairy has been piloting the BIDA® System on his dairy in Royal City, Washington for the past 18 months with phenomenal success. Allred’s farm has been able to reduce their Total Suspended Solids (TSS) by 99% and reduce total Nitrogen (TKN) by 83%. 

Russ Davis, President of Organix, a distributor of the BioFiltro, is happy with the success he’s witnessed with this system.

“For the last fifteen years we have been searching with our dairy clients to try to find an effluent treatment tool that can successfully integrate on a dairy,” said Davis. “Most systems are either overly complicated, too expensive, or create a residual sludge.  The BioFiltro concept appears to have addressed those issues - it's cost effective, easy to operate, uses elementary principles that nature has proven for eons, has minimal maintenance and the byproduct is a high value soil amendment.”

Royal Dairy has a flush system in their barns which cleans the wastewater out of the barns and into a centrifuge. From here, the liquid and solids of waste are separated and the liquid waste makes its’ way to the lagoon. Another set of pumps propel water from the lagoon to the irrigation system that runs along the surface of the 4-walled concrete open-top structure.

For a few minutes every hour, the irrigation system distributes the liquid waste across the system surface where the water percolates down through a layered bed of (top- to bottom) wood shavings, gravel, and then finally drainage basins before hitting the concrete floor where it flows out via the exit pipes and is pumped into storage ponds. BioFiltro combines physical filtration with biological by inoculating the woodshavings media with an industry specific mix of microbes, bacteria, and worms which work symbiotically together to form a digestive biofilm across all system medias.

The number of worms can vary, and is related to the strength and nutrients of the influent wastewater, but some systems have as many as 12,000 per cubic yard. As the worms burrow throughout the wood shavings layer in search of large solids, they naturally create air channels which provide aeration to the system. Furthermore, as the worms eat, they excrete castings that are full of aerobic bacteria and microbes that stick to wood shavings and rocks to capture and digest waste as water percolates down.

The final water quality is ideal for irrigation in crops while the leftover solids of the BIDA® System are worm castings, recognized by many as one of nature’s most valuable soil amendment. These solids only need to be removed from the system once every year and a half and Allred plans, among other things to use it on his own field.

On top of the reusable benefits of the system, it also significantly reduces greenhouse gases (GHGs) and unwanted nitrogen emissions. In fact, the system has proved to reduce both GHGs and nitrogen emissions to a great extent.

Dr. Frank Mitloehner, Ph.D. Professor and Air Quality Extension Specialist at U.C. Davis has been working with this technology since 2013.

“Some give all the credit to the worms, but I found the same success with this system just utilizing the aerobic microbes before the worms were added,” stated Dr. Mitloehner. “While these are very encouraging results, to be proven, we need to keep replicating this technology.”

Allred is currently extending his pilot structure to an 81,000 sq. ft. plot His plan is to have all water from his farm being processed by the BIDA® System by July 1 of this year.

“In the next 5 years the biggest challenges will be on the backside of the dairy,” said Allred. “It isn’t going to be about how we treat cows or what we feed them. The challenges now are with nutrient management; greenhouse gases are next. My pilot system has taken care of all these issues which is why I’m moving forward with the installation.”

Allred stated he has had several dairy farmers, government agencies, and other businesses visit his farm to see how the system works, all of which have been impressed and interested in the project.

“I want to be dairy farming in 50 years and I can almost guarantee in 50 years we’re going to have to do something like this,” said Allred. “There are a lot of necessary improvements to be made in the way we handle the backside of the farm.”

Davis sees a bright future for this technology and is eager to see it in more dairies.

“BioFiltro's clients talk in terms of how surprised they are that the system exceeds their expectations," said Davis. “This is going to be a very good development for dairies locally and nationwide." 

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