By RACHEL IOVAN
Capital News Service
LANSING — The latest round of Department of Agriculture (MDA) grants will promote new cost-effective ways to manage wastewater from food processing — a rising concern in growing specialty crops.
The grants to companies in Frankfort and Grand Haven and to Michigan State University are part of a larger initiative to enhance the state’s agriculture industry, including food processing, said Michelle Crook, an engineering specialist at MDA.
Of the $1.4 million Michigan received for agricultural development ventures in federal dollars, $196,200 will be divided among three projects focusing on wastewater practices.
“There is a lot that is unknown about the science. We are still looking for new techniques to treat wastewater,” Crook said.
Specialty crops include fruit, vegetables and greenhouse crops.
Processors have traditionally applied wastewater on a limited number of acres in an economically and environmentally effective manner, said Crook.
In the last few years, however, the Department of Natural Resources and Environment started seeing problems with high amounts of carbon in soil, she said.
Crook was part of the committee that reviewed grant applications.
Processing of specialty crops results in higher amounts of carbon in wastewater because of the natural sugars washed off fruits and vegetables.
“Fruit and vegetables produce more wastewater because, depending on the product, they may need to be cooled, cut up, rinsed or packaged,” said Ken Nye, a commodity specialist for the Michigan Farm Bureau.
By comparison, corn and soybeans, which aren’t specialty crops, aren’t rinsed after harvesting, so their production results in less wastewater, Nye said.
Steve Safferman, an associate professor of biosystems and engineering at MSU said the most common technique for disposal is to irrigate the soil with wastewater and let the land naturally filter it.
But, if the soil is saturated for too long, carbon in the wastewater may sink deep into the ground, depleting oxygen and causing an environment that alters metals in soil, such as iron, manganese and arsenic, he said.
“These metals occur naturally in the soil in small amounts, but when excess carbon is absorbed, the metals can mobilize,” said Safferman.
The metals may then seep into groundwater, and could contaminate water sources.
Crook said, “We don’t know yet if the nutrient content or the volume is the problem, or if the soil needs a longer resting period so it can become aerobic again.”
Elaine Brown, executive director of Michigan Food and Farming Systems in East Lansing, said the industry must find where environmentally sound food wastewater management and economic feasibility intersect.
Lakeshore Environmental Inc., a consulting firm in Grand Haven, received a $46,200 grant to look into alternatives of wastewater filtration, according to Joel Kenyon, project director for the company. Its experimental technique is called freeze crystallization.
With the new method, wastewater goes through a pump that separates the filtered water from the chemicals.
As the clean water freezes, it turns into snow, which concentrates the remaining chemicals that can’t freeze. A much smaller amount of impure water remains, because most of the purified water has already been extracted, Kenyon said.
“Instead of treating thousands of gallons, we can significantly reduce the amount of water that needs to be treated,” Kenyon said.
Treatment costs depends on several factors, primarily quantity.
“Most food processors have excellent wastewater treatment,” said Kenyon, “but everybody is looking to lower cost.”
Kenyon said that Lakeshore Environmental is trying to take advantage of Michigan’s cold winters to help with the freezing process.
“The main question is, if you install this system, can it be integrated to cause a big cost reduction,” said Kenyon.
MSU’s Safferman, said that installation of wastewater processing systems is expensive and may take eight to 10 years to pay off, which is a long payback period in the agriculture industry.
The other two grants were $75,000 for a MSU study of the effects of poplar tree growth on disposal of wastewater and metal contamination of groundwater, and $75,000 to Smeltzer Orchard Co. in Frankfort to look at keeping soil oxygenated so bacteria can digest wastewater.
By RACHEL IOVAN