Wastewater biosolids enrich local crop soil

Date: Monday, November 28, 2022

Land application program provides free fertilizer to metro farmers

A farmer on a tractor spreads biosolids on a field.The rain had just stopped when the first truck arrived at Peine Farms on a cold autumn morning. Over the next eight days, a steady stream of trucks followed, each loaded with fertilizer for 400 acres on the 7,500-acre cattle farm in Cannon Falls. But something was different about this fertilizer: it was biosolids delivered directly from the nearby Empire Wastewater Treatment Plant.

Peine Farms is one of several farms in or near Dakota County that has partnered with the Met Council to use wastewater biosolids as a powerful organic fertilizer. Most farmers use it to fertilize fields that produce feed crops for animals.

Our Empire Wastewater Treatment Plant Land Application Program employs a comprehensive, multi-step process to turn wastewater from bathing, laundry, toilets, kitchens, and other sources into biosolids that are transported to nearby farms and spread early in the spring or immediately after fall harvest. The Environmental Protection Agency and Minnesota Pollution Control Agency oversee the program, monitoring quality standards and best management practices.

Even better, farmers can participate in the program for free.

Making the most out of waste

“We’re always searching for new ways to optimize waste and improve sustainability,” said Mike Lindquist of Peine Farms. “We don’t want to take anything more from the land than we put into it. This program allows us to offset rising food and energy prices while enriching the land with natural micronutrients to help plants thrive and increase yield.”

Lindquist estimated that about 18 tons of biosolids were used for each acre, which required hundreds of transported loads. After the biosolids were dumped in the field, payloaders, tractors, and tillers helped spread them evenly. In the spring, crews will plant corn to feed cattle on the farm. It’s the first year that Peine Farms has participated in the program. Lindquist is optimistic it won’t be the last.

“Successful farming is more of an exact science than many people realize,” said Lindquist. “From the extra precautionary treatment steps at the plant to the careful application in the field, I’ve been impressed with the program. I thought the team did a phenomenal job applying the fertilizer with the consistency we needed.”

Realizing the value of biosolids

A tractor with a disc attachment adding biosolids into the field.Naturally, biosolids offer unique benefits when compared to commercial fertilizers. Biosolids do more than feed the plants, they feed the soil, too. Healthy soil has its own dynamic ecosystem, full of organisms and nutrients to help curb plant disease, weeds, and pests. Biosolids hold nutrients near the soil surface and slowly release helpful nitrogen and phosphorus. As a result, there’s more water retention and less runoff and erosion.

“Crops like corn only perform to their most limiting factor,” said Lindquist. “By the time the fertilizer gets to us, the Met Council has removed all the harmful pollutants so it’s mostly just the good nutrients.

Turning wastewater into healthier crops

The Empire Wastewater Treatment Plant produces biosolids through a natural biological process that breaks down pollutants, kills germs, and generates a renewable fuel called biogas. The biosolids are stored at the plant and transported to regional farms during the spring or fall. In turn, the biogas is used as fuel to produce heat and electricity at the plant.

Biosolids for commercial land-spreading are processed and dried at the Empire Wastewater Treatment Plant.“Farmers have been environmental stewards for centuries, repeatedly reimagining best practices to sustainably grow food,” said Colton Janes, business unit manager for the Met Council. “Likewise, we’re trying to do our part by creating reusable resources that can help them be more profitable while protecting our environment.”

Before each land application season, biosolids from the Empire Plant are tested for solids content, pH, nitrogen, phosphorus, potassium, and trace metals. The farmers collaborate with the Met Council to determine application rates, largely based on current and past farming practices, specific crops, and soil health.

The Met Council doesn’t just dump the fertilizer and leave. We work directly with farmers to manage odors, dust, traffic, and even road wear-and-tear from the envoy of trucks delivering biosolids.

“There’s value in everything,” said Lindquist. “Working with the Met Council enables us to improve our best farming practices, protect the environment, and save money. It’s a win-win for everybody.”

Empire Wastewater Treatment Plant Land Application Program

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