EAST LANSING, MICH. — The Michigan Alliance for Animal Agriculture — a partnership among Michigan State University (MSU), the Michigan Department of Agriculture and Rural Development, and animal agriculture industry groups — funded two projects at MSU to gain a better understanding of the effectiveness of wastewater treatments, particularly for small meat processors.

“There are relatively few options for low-volume meat processors when it comes to wastewater,” said Jeannine Schweihofer, associate director of MSU Extension’s Agriculture and Agribusiness Institute. “The ultimate goal of this research is to provide processors with cost-effective wastewater management strategies while protecting groundwater and the environment.”

The first project published its results in the journal Water in February 2024. The study selected six Michigan meat processors to analyze the wastewater they produced. Over the course of a year, researchers collected samples six times to screen for total nitrogen, ammonia, nitrate, phosphorus and other compounds.

“Samples need to be taken as close as possible to the time of discharge to be accurate for what is actually being discharged,” Schweihofer explained. “For example, if we take a sample a month after a lagoon is emptied, then the lagoon doesn’t have time to do its job, and the levels will be high. But that isn’t what is being discharged.”

Through the samples, researchers characterized the facilities’ wastewater, which is important to meet local groundwater discharge permits.

Permit requirements established in 2020 pose a challenge for small businesses, according to Dan Swartzendruber, president of the Michigan Meat Association.

“Many of the small processors are fighting to remain in business with the rising costs,” he said. “With the new permit mandates, it may force these processors to invest in water treatment systems that will cause them to either close their plants or face long-term debt that would prevent them from being able to offer competitive wages and benefits to their employees.”

To adhere to newer standards, researchers suggested potential solutions, including pretreatment in multiple lagoons to allow more time for the breakdown of compounds, adding aeration or filters, and gaining a better understanding of soil capacity to ensure the soil can deal with the volume of wastewater.

The second MSU project is ongoing, addressing site-specific needs for processing facilities. Researchers are evaluating a variety of treatment and discharge methods, developing a decision-support tool for producers to determine which option is ideal for them, and identifying best practices for wastewater reduction and management.

“The results from our initial work indicate that even simple decentralized wastewater treatment systems that use techniques such as aeration and filtration, combined with facility management practices, can substantially reduce or improve permitted wastewater characteristics,” Schweihofer said. “We know that small business owners are always looking at how new practices affect their bottom lines, and we also know that needs are different for each producer. We want to show that there are strategies that make economic sense, in addition to improving the industry’s sustainability.”