Ishpeming Wastewater Treatment Plant leaps to forefront of industry innovation

Some who roam into Ishpeming may think the Country Village is the crown jewel of town, but these days Ishpeming has a lot more to brag about--namely, a municipal waste biosolids plant that not only runs on renewable resources but is the first of its kind in Michigan.

The plant, located at the Ishpeming Area Joint Wastewater Treatment Facility, combines municipal solid waste with the wood cuttings or shavings that result from tree cuttings to form a soil amendment that can be used for landscaping and gardening. The finished product has tested as being 99 percent pathogen-free as well as guarded against salmonella and is well below the U.S. Environmental Protection Agency's limits for metal traces.

Facility director Deborah Pellow says the idea for the biosolids facility was a matter of heavy discussion and research for the facility's authority board, which makes all major decisions and consists of two representatives from the city of Ishpeming, one from Ishpeming Township and one from the Marquette County Health Department.

"Approximately seven years ago this authority board was faced with increasing costs to dispose of our biosolids at the landfill. Class B biosolids can be used on farmers' fields for certain crops but those are very limited in the Upper Peninsula. So the board decided to look at a class A product," she says.

Class A biosolids are those where infectious agents are below required detectable levels and must meet specific criteria for distribution to the general public. Class B solids are those where infectious agents are unlikely to pose a threat to public health as long as it is used specifically for agricultural land.

Pellow adds that after several types of systems were evaluated, the in-vessel system appeared to be the most effective for the U.P.

In-vessel composting involves housing the waste material in 14-by-12-foot composting vessels and heating it to kill pathogens. After three consecutive days at 131 degrees, 14 consecutive days at 113 degrees and a total of 80 days in the vessel, the compost is formed.

"In-vessel composting is done in Canada where the weather is colder for longer periods of time. Composting has been around a long time and it is tried and true. Given enough time, temperature and energy you can turn waste into a reusable product," she says.

Construction on the new Ishpeming facility finished earlier this year and the vessels were filled for the first time in February, with the first batch of finished product finished in late March. By June, the soil amendment was sold to the first customers, which are both commercial and residential.

"We have a contract with a local landscaper to purchase in bulk, large amounts of compost mixed with top soil," Pellow says. The material also is sold directly at the facility by the pick-up truck load.

The biosolids facility is expected to produce up to 8,500 square yards of the soil amendment per year, providing both financial and environmental benefits to the plant and the community.

"We were faced with landfill costs of more than $120,000 per year. Our woodchip cost is around $60,000 annually and we should see a revenue source of the end product in the area of $30,000 per year. Aside from the fact that environmentally this is the right thing to do, we are saving on filling the landfill, greenhouse gas emissions and it is costing the user of our system far less by composting," Pellow says.

Downstate Michigan houses similar composting facilities, but Ishpeming's is the first in the state that uses the in-vessel system.

"As it gets harder and harder to find places to dispose of class B biosolids, the option for us was to produce a recycled, reusable product, which becomes a very viable option for wastewater treatment facilities," she says.

So far, Pellow says public interest in the facility's soil amendments is high, and those who have used them have come back for more. The composting is a success so far, and may even point the way toward a more sustainable future for other wastewater plants in the U.P.

Becky Korpi is an Ishpeming-born Yooper and freelance journalist. She is also a Returned Peace Corps Volunteer. She can be contacted via email.