Byproduct of wastewater treatment fertilizes crops

The Clermont County Water Resources Department will try this year to expand its beneficial land application program for the disposal of biosolids generated at the department’s wastewater treatment plants.

According to Clermont Director of Utilities Tom Yeager, the department began providing the byproducts of wastewater treatment to local farmers for use as fertilizer in their fields last spring after discontinuing the program in 2005.

“We used to do beneficial land application in the past but we got away from it about five years ago,” Yeager said.

He said the program was reintroduced last year under the direction of Assistant Director of Treatment Dwight Culbertson as a way to offset treatment costs and provide a mutual benefit to the farmers and the community. The county distributed about 38.5 percent of the biosolids generated at its eight wastewater treatment plants over 350 acres of fields in 2010.

“It’s beneficial to the agricultural community and it keeps it out of the landfill,” Yeager said.

This year Yeager said his department has set a goal of using 50 percent of all biosolids generated at the county treatment plants for beneficial land applications. Culbertson said the county netted about $90,000 in savings through the program while the farmers saved a net of about $42,000 in fertilizer costs.

“We’re providing the material to the farmers for free at this point, so it’s a good deal for the farmers and we save about $15 a ton by not landfilling the material,” Yeager said.

Culbertson describes the wastewater treatment process as an acceleration of nature’s process of breaking down human waste.

“We do what nature does in weeks and months in a day,” Culbertson said. “We maintain a culture of organisms that break down the waste.”

All non-organic materials are filtered out of the wastewater at the beginning of the process before the culture, known as activated sludge, reduces the pathogens and treats the water for contaminants. The process eliminates 96 to 98 percent of all pollutants and after the micro-organisms have depleted their food supply they begin attacking each other. The organisms that die are collected and dried. The resulting biosolids are then disposed of using one of three methods. In large municipalities they are burned in an incinerator. In smaller communities the biosolids are either shipped to a landfill or applied to fields.

According to the Ohio EPA’s most recent data, the year before Clermont County reinitiated their beneficial land application program 46.8 percent of all state monitored sludge was land applied, another 33.4 percent was incinerated, and 19.7 percent was sent to landfills.

“Basically, the organic portion of our waste water is returning to the land from which it came, otherwise we’ll just keep taking it out and eventually we’ll deplete the soil,” Culbertson said. “Our biggest challenge in the future will be achieving environmental sustainability.”

In addition to providing nitrogen and other valuable nutrients for the crops, the biosolids also alter the texture of the soil. The result is a loose soil that retains more water and provides more air to roots, something chemical fertilizers do not provide.

The process is heavily regulated by the Environmental Protection Agency and requires extensive testing, which is being paid for by the county. All fields need to be tested and permitted before they can be used. Yeager said the fields must meet requirements for drainage and soil content and the field must be large enough to provide a sufficient buffer for its neighbors.

“We’re looking for predominantly agricultural areas so we can keep some separation from residential areas,” Yeager said. “Larger fields are better because we can keep it away from the edges. We also have to be careful with the lay of the land and watch for runoff. The material has to stay where we put it.”

The fields which received biosolids last year ranged between 24 acres and six acres. The EPA monitoring requires testing be done in 20-acre tracts. Culbertson said the permit process takes about three to four months. Once a field receives a permit it is retested every two years to monitor the level of nutrients in the soil.

The biosolids are also heavily tested. Culbertson said each batch is tested for volatile organic compounds and other pollutants before it even begins the drying process and if it does not meet the EPA’s strict requirements it is sent to a landfill.

The biosolids can be applied to fields being used for a number of crops. Yeager said the biosolids are applied to corn and soybean fields early in the spring while farmers are tilling, however the biosolids can be applied to hay fields throughout the growing season. The nutrient content is closely monitored and fluctuates depending on the nutrient requirements for a particular crop.

Yeager said the Water Resource Department is soliciting volunteers for the program and is working with the Farm Bureau and the Clermont County Soil and Water Conservation District to locate farmers whose fields qualify. Yeager said the county also provides free delivery to the fields.

“It’s a smart use of resources and we’re rather supportive of it as long as it’s done properly,” Yeager said.