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GRWyoming biosolids partnership preparing to pump
A partnership between the cities of Grand Rapids and Wyoming launched six years ago to share the cost of processing sewage sludge for recycling has come to fruition, with formal dedication events taking place Tuesday at both of the cities' sewage treatment plants.
In 2003, both communities were facing the need to expand or replace their current systems for processing sewage sludge, now commonly referred to as biosolids. The partnership was arrived at when both communities realized it would be more cost effective to share one large facility rather than each building its own.
Wyoming has long been disposing of some of its biosolids on agricultural lands, and paying to have the rest dewatered and dumped in commercial landfills. All of Grand Rapids' biosolids have been dewatered and hauled to commercial landfills.
The dedication ceremonies this week mark completion of a 3.5 mile pipeline built from the Wyoming treatment plant to the Grand Rapids treatment plant, where a newly constructed "dewatering" facility will use centrifuges to remove the water from the biosolids, much like the spin cycle in a washing machine.
The partnership, now called the Grand Valley Regional Biosolids Authority, invested about $34 million in the 12-inch pipeline, pumping station and dewatering facility.
According to the federal Environmental Protection Agency, biosolids are nutrient-rich organic materials resulting from the treatment of domestic sewage in a treatment facility. The EPA also provides a shorter definition of biosolids: "treated sewage sludge."
Randall Fisher, manager of the Grand Rapids Environmental Services department, said that when the GVRBA partnership was originally formed six years ago, "we were envisioning something perhaps a little bit grander in scale. We were thinking in terms like anaerobic digestion and recovering the methane, and then using that to produce electricity."
They also considered producing a Class A biosolid that would be heat-dried, pelletized and sold as fertilizer. The EPA says that Class A biosolids is treated sewage sludge that is deemed to be of "exceptional quality" because it contains no detectible levels of pathogens and, in general, can be used as fertilizer.
Fisher noted that many years ago, the city of Grand Rapids bagged and sold its treated sewage sludge to individuals for use as fertilizer, a practice many other communities in the U.S. also followed.
Fisher said when the wastewater treatment representatives from the Grand Rapids/Wyoming biosolids partnership began working with a consultant, they learned that the cost per dried ton to produce Class A biosolids "got to be fairly expensive," so the municipal leaders backed away from that idea.
"What we decided to do is to look at a phased approach," said Fisher, with the first phase linking the two municipal treatment plants together so that liquid biosolids from the Wyoming Clean Water Plant at 2350 Ivanrest Ave. SW can be pumped to the Grand Rapids treatment site on the southwest side of the city near the Grand River. (At the end of the sewage treatment process, the relatively clean water is safely disposed of in the Grand River.)
The pipeline and dewatering process is "going into the start-up and performance testing" stage, said Fisher.
Any further processing of the biosolids at this time is "kind of on the back burner right now. The thought is, let's get this phase one up and running smoothly, and then the communities can look at all the options out there."
"There's really no schedule yet for when we would move into a phase two, but by getting it to this phase one step, it opens up a world of opportunities," said Fisher.
Up to now, the city of Grand Rapids has contracted with Synagro Technologies to dewater its biosolids and haul them to commercial landfills. Synagro, based in Houston, claims to be the largest recycler of organic residuals in the United States, serving more than 600 water and wastewater treatment facilities in the municipal and industrial sectors throughout the United States
During the warmer months of the year, Wyoming's liquid biosolids are hauled to farms in the region where farmers allow it to be tilled into their soil as fertilizer and soil conditioner. However, during the coldest months of the year when the ground is frozen, environmental regulations prevent use of the biosolids on agricultural land, so the Wyoming biosolids must be dewatered and hauled to a landfill. Wyoming saves money on landfill tipping fees when its biosolids can be applied to agricultural land.
The new GVR Biosolids Authority operation will send its dried biosolids to two major commercial landfills in Ottawa County, which both recover methane and sell it. Ottawa County Farms near Coopersville is a large, privately owned landfill where recovered methane has been used to generate electricity since 1997. The generation plant there now produces almost 6.5 megawatts, enough to power a small residential community.
The Autumn Hills landfill in Zeeland Township is owned and operated by Waste Management, which sells its recovered methane to North American National Resources Inc., which compresses it and sends it via pipeline six miles to Zeeland Farm Services. ZFS then converts it to heat to dry soybeans. The gas compression station at the landfill can process up to 4,000 standard cubic feet of gas per minute.
Fisher said biosolids are a welcome ingredient in landfills where methane is recovered, because biosolids are "high in microorganisms that help accelerate the decomposition process," which releases methane gas.
He said the GVRBA dewatering facility, which will be operated by municipal employees, will produce "about 50 dry tons (of biosolids) per day." The cost of the pumping station, pipeline and dewatering facility was shared in proportion to the amount of biosolids generated by each community, so Grand Rapids pays a larger share than Wyoming, according to Fisher.
The Grand Rapids wastewater collection system covers an area of approximately 200 square miles, with its treatment plant processing sewage from about 300,000 households in the city of Grand Rapids and 14 surrounding cities and townships.
The Wyoming Clean Water treatment plant has a capacity of 24 million gallons of waste water per day, generated by about 140,000 people. Like Grand Rapids, Wyoming's waste water is cleaned and released into the Grand River.