October 21, 2011

For Additional Information:

Shelly Houston, Meridian Mayor’s Office

(208) 489-0531


Note: Photo/Video Opportunities can be arranged for the mobile biosolids processing equipment during Meridian’s pilot program period (October 24-28)



City of Meridian to Test New Way to Process Biosolids

Grass Clippings to be Used for First Time in Patented Lime Stabilization Process


Meridian, ID - (October 21, 2011) - The City of Meridian’s Wastewater Treatment Facility will be testing a new system which processes biosolids through a patented lime stabilization process.  This pilot program will take place October 24-28 using mobile equipment on loan from Schwing Bioset, Inc (SBI).  


“As part of the Wastewater Treatment Facility’s goal to become self-sustaining, they are exploring innovative approaches to resource management such as water reclamation, power generation, and nutrient recycling. Biosolids recycling is a major component of this endeavor and we look forward to seeing the results of this pilot project,” according to Meridian Public Works Director Tom Barry. 


Biosolids are the processed solids from City’s municipal wastewater treatment facility and are a renewable resource. As a renewable resource, biosolids can be safely treated and returned to the soil and reused as a nutrient rich soil amendment.  Processes such as lime stabilization or composting are treatment means by which these organic materials are converted for reuse. Biosolids can be recycled alone or with other renewable resources such as grass clippings. 


“Our Public Works Department is encouraged to explore and pilot technologies and processes with our wastestream that provide an economic benefit to our rate payers and promote environmental stewardship and responsibility as well.  Best of all, this is a public/private partnership with Schwing Bioset that has minimized the cost of the pilot project,” said Mayor Tammy de Weerd. 


The Schwing Bioset treatment process involves lime stabilization and pasteurization. Biosolids are blended with lime and sulfamic acid under pressure within a reactor.  This pilot project will introduce grass clippings and leaves into the Schwing Bioset treatment process for the first time.  This will help determine the viability of using this lime stabilization process to address the full composting needs of the community.


“A unique feature of Meridian’s pilot program is the new element of adding grass clippings to the biosolids and running them through the lime stabilization process concurrently.  Schwing Bioset has not done this before in any of their previous demonstrations and expressed interested in processing these comingled materials as well,” says Mollie Mangerich, Environmental Division Manager of the Public Works Department. 


Sanitary Services Company (SSC) is bringing about five tons of grass clippings from their Transfer Station for this purpose. “SSC’s involvement and provision of their operational resources has added value to this pilot program.  We’re fortunate to have such a great partner in this project,” added Mangerich.


Upon completion of this pilot project, the City of Meridian will be provided a report detailing the results of the pilot program including analysis of the throughput times, volume of materials processed, amount and cost of process chemicals required, analytical results of product generated and staffing and labor requirements. 


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The City of Meridian is located at the center of the Treasure Valley in southwest Idaho, minutes from the State Capitol. Founded in 1893 and incorporated as a city in 1903, Meridian is now one of Idaho’s largest and fastest growing communities. As the home to many young families, Meridian is a vibrant community whose mission is to be a premier city to live, work and raise a family and was selected in 2010 by Family Circle Magazine as one of their Top 10 Best Cities for Families, by Money Magazine as one of its 100 Best Places to Live, and by America’s Promise Alliance and ING as one of the nation’s 100 Best Communities for Young People For more information about Meridian, visit