News from Schwing Bioset

Lime Stabilization-Fact vs. Fiction(myth-busted)

As you can imagine, working with sludges and biosolids brings up a number of concerns, from the basic to the technical. At the very basic, there’s “does it have an awful smell?” It’s a natural enough concern—we’re working with human waste, after all. But is there a terrible smell?

Class A Biosolids
Not at all, thanks to the Schwing Bioset process. A pinch valve flattens the sludge flowing out of the reactor, creating additional surface area to allow the ammonia and other compounds to be released and subsequently captured and scrubbed under the collection hood. The smell, overall, is akin to wet concrete (because of the lime content). In fact, in many instances the Class AA product produced by the Schwing Bioset process is stored outdoors on the edge of town with residential homes within sight.
At the more technical end, other lime stabilization systems are plagued by poorly mixed lime and sludge. Schwing Bioset solves this with a twin auger mixer that ensures the lime and sludge are thoroughly combined.
Another common concern is that the lime/sludge dust will make for a tough work environment. But the Schwing Bioset process is a closed system with a sealed mixing hopper—and that ensures the dust stays inside the machine, and not your lungs.


Tags: Biosolids Process, Bioset Process, Bioset Class A, Fertilizer Replacement, Biosolids Handling



Class A biosolids are completely safe for a variety of land applications. The end product is basically aerated soil that has beneficial levels of nitrogen, phosphorus, and potassium. The Class A product from a Bioset System has slightly elevated levels of lime as a result of the alkaline stabilization process. The alkaline reaction is as follows:
    CaO + H2O => Ca(OH)2  + 490 Btu/lb of heat

The by products of the reaction between quick lime and water are lime and the heat used to kill pathogens. Acid is also used to create a secondary reaction with the lime (Ca(OH)2) that can make up to an additional 400 Btu/lb of heat to accelerate pathogen kill. The end product has a PH of greater than 11.5. Long term tests have shown that this process maintains its PH several months after processing. This is important because some process can only reduce pathogens to safe levels for a short period of time when the material is dry. If pathogens are not thoroughly killed by treating extensively, then rain water and moisture can reactivate the pathogens in the soil and make them unsafe.   

The end product is used as a fertilizer because it is safe with no pathogens and rich with nutrients. Nitrogen and Phosphorus are the sought after nutrients in the planting soil industry, creating value for this material as a soil additive. There are also benefits from organic components in the material resulting from the original biological material.

Having a basic material (PH is higher than 7) from the lime content is an advantage as a soil amendment to help balance out acidic soil as well as fertilize. Acidic soil is found across the U.S. as a result of acid rain and other natural or manmade conditions. There are small treatment plants that will give this material away to locals as a free fertilizer for gardening. Some moderately sized facilities have contracts with farmers that can use the material to balance out soil and fertilize without buying costly lime and fertilizer additives. Contracts have also been established to sell the end product to golf courses in Florida, a region known to have highly acidic soil. Balancing the PH and providing a healthy fertilizer for the greens, while reducing maintenance costs.     

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Tags: Class 'A' Biosolids, Biosolids, Bioset Class A, Fertilizer Replacement

Natural Fertilizer from Biosolids, reuse to the Nth degree:Part I

Learn more about how we are seeking to make a difference in our communities by beneficialy reusing biosolids, creating jobs and mininmizing the risks associated with Class B Biosolids. By creating a Class A biosolids with a natural process.

Tags: Biosolids Process, Wastewater Treatment, Bioset Class A

Schwing Bioset featured on 21st Century Business Television

(EMAILWIRE.COM, July 30, 2009 ) Boca Raton, FL --- Schwing Bioset, Inc. (SBI) was created in 2006 by spinning off the Material Handling Division of Schwing America into its own company. The new company was created to better focus on meeting the unique needs of the wastewater treatment industry. In addition, the spin off afforded Schwing Bioset, Inc. the ability to leverage its two-decades of successful wastewater treatment installations at Schwing America into an aggressive pursuit of alternative “green” solutions in the wastewater treatment industry.

In 2006, SBI opened a new 20,000 square foot engineering and manufacturing facility in Somerset, WI in order to rapidly expand its service offerings. The “Bioset Process” and Fluid Bed Drying technology are two examples of Schwing Bioset’s commitment to delivering innovative and environmentally friendly solutions to the wastewater treatment industry.

SBI's Project Management and Fluid Bed Drying teams remain in their respective locations of Danbury, CT and Houston, TX. Schwing Bioset’s mission is simple, to become the market leader in the biosolids and beneficial reuse industry.

For more information, visit

JL Haber, Vice President of Programming at Multi Media Productions, adds, “Schwing Bioset is an exciting company with a unique mission. We are excited to have them as a guest on our program.”
About 21st Century Business
21st Century Business airs on CNBC and the Fox Business Network as paid programming. 21st Century Business may also be viewed through video on demand via The 21CBTV Series is also available at more than 90 prestigious universities, including Carnegie Mellon University, Howard University, Dartmouth College, and Georgetown University.

For specific market-by-market air dates and times, please e-mail For more information, please visit

Tags: Bioset Class A, Schwing Bioset

West Central Wisconsin Biosolids Facility, Ellsworth, WI

April 2009

Schwing Bioset has completed start-up of a new Bioset Class A lime stabilization system at the West Central Wisconsin Biosolids Facility (WCWBF) located in Ellsworth, WI. The WCWBF serves as a regional facility for more than ten local communities offering strictly dewatering and residuals management services.
The WCWBF had an existing Class A lime system that mixed biosolids with lime and fly ash. That system was plagued by continual mechanical failures and extreme dust and odor issues for nearly the entire 10-year span it was in operation.

The WCWBF hired Town & Country Engineers of Madison, WI to review available Class A technologies and evaluate the proposals received from the short-listed vendors. After studying other Class A technologies and touring other available alkaline stabilization systems (including another technology that utilizes supplemental heat) only two proposals were solicited - a replacement of the existing system, or a Bioset system from Schwing Bioset.

The WCWBF selected the Bioset process because it offered a lower cost proposal that also:

  • Greatly reduced the volume of Class A material produced
  • Contained dust and minimized odors in the enclosed vessel
  • Provided a consistent Class A material
  • Produced a material that was free of the metal contaminants that are present in fly ash additives.

As the WCWBF has no significant up-stream storage capacity the new equipment needed to be installed and operational within one week. Schwing Bioset met this need by providing the installation and commission services with its own installation crew.
The facility is already reaping the benefits of the improved Class A product as a revenue stream. Historically the WCWBF had to pay local Contractors to have the other material removed. Now, Contractors are paying the WCWBF for the Bioset material which is being used as a substitute for agricultural lime and fertilizer.

Schwing Bioset has completed start-up of a new Bioset Class A lime stabilization system at the West Central Wisconsin Biosolids Facility (WCWBF) located in Ellsworth, WI.

Tags: Biosolids, Bioset Class A, Schwing Bioset

Stewartstown Installation

July 2008

Schwing Bioset is pleased to announce the start-up of the new Bioset Class A lime stabilization system at the Stewartstown STP in Stewartstown PA. Stewartstown is a growing community between York, PA and Baltimore, MD.

Like many communities, Stewartstown understands the importance of beneficial reuse but was concerned with odor issues due to the proximity of residential areas near the plant. The key features that attracted Stewartstown to the Bioset process were the odor control, dust control and the flexibility to design the equipment to fit into their existing available space. The process is fully enclosed containing odors and dust during treatment. The technology is also compact and was customized to fit in an existing garage bay, eliminating the need for additional structures or odor control equipment.

The low maintenance and operating cost along with the overall system reliability prove to be an excellent solution for Stewartstown to consistently produce a product that is safe, inexpensive, and in demand.

Stewartstown Installation

Tags: Biosolids, Bioset Class A, Schwing Bioset, Lime Stabilization