SCHWING Bioset - Products - Bioset Process

Bioset Process - Class A Biosolids

Complete Recycling with Lime Treatment

The Bioset process achieves Class ‘A' biosolids via the time vs. temperature equation and pH adjustment per the EPA 503 regulations. Temperature is achieved through the addition of Quicklime and Sulfamic acid and the high pH is achieved through the addition of the Quicklime. Biosolids and chemicals are homogenously mixed in a Schwing Bioset twin screw feeder and pumped with a Schwing Bioset piston pump through an insulated reactor.

As the Bioset process is totally enclosed within the reactor the process operates odor free. The reactor discharge provides the only location for gases to volatilize off and they are easily collected and scrubbed utilizing a small water scrubber. The resulting final product has an odor that is similar to wet-concrete.

The following features of the Bioset process make it an attractive solution to many small and large Wastewater Treatment Plants.

A simple system that is easy to operate
System that requires little maintenance
System that provides a consistent Class A product that offers long-term stability
System that operates virtually devoid of dust and odors
System that provides a low cost solution

Photo tour of typical installation

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Consistent and reliable operation

One of the most important features of the Bioset process is that it consistently and reliably produces Class A EQ biosolids from start-up to shut-down. Biosolids that remain in the reactor on shut down achieve Class A EQ status in the reactor and are discharged as such upon start-up. Unlike competing Class A processes there are no operating scenarios, including start-up and shut down, where the Bioset process does not produce a Class A biosolids.

General housekeeping

The Bioset process is a clean system to operate as it is totally enclosed from start to finish. Being totally enclosed prevents dust and odors from escaping at the inlet, prevents biosolids from spilling during the process, and allows point source odor capture at the discharge.

No supplemental heat

All of the heat to operate the Bioset process is achieved via chemical addition. No expensive and maintenance intensive supplemental heat sources are required.

Long term stability

Unlike other alkaline stabilization processes that utilize supplemental heat to reduce lime dosages and subsequently lose the high pH shortly after processing, the Bioset process maintains Class A EQ status months after processing.

Maintenance

The Bioset process has few moving parts and therefore few maintenance requirements. The primary component that requires maintenance is the Schwing Bioset piston pump. Since the Bioset process operates at less than 10% of the pumps rated operating pressure, the wear rates are nominal.

Reduced operating costs through PFRP approval

PFRP approval to reduce the operating temperature is possible as the ammonia that is generated through lime addition is entrained with the biosolids inside the reactor and kills the pathogens. One Bioset installation presently has received approval to operate at 55C with a residence time of 25 minutes (versus 70C for 30 minutes) and three other installations are presently in the process of gaining similar approvals. The most significant impact of this approval is the approximately 35% reduction in operating costs.