News from Schwing Bioset

Southerly sets the standard with solids disposal efforts

Problem Solvers (as seen on

Problem: Increased solids volume after construction project increased overall capacity.
Solution: Pumps and sliding frames enable cake disposal.

The Southerly Wastewater Treatment Plant, which serves most of the greater Columbus, Ohio, area, recently completed a 5-year, $350 million expansion. The expansion nearly tripled its peak capacity from 431,500 to 1.25 million m3/d (114 to 330 mgd). The plant has earned numerous awards for plant and employee performance, but its solids disposal program truly makes Southerly a standout.

Using a quartet of heavy-duty pumps and a number of sliding-frame components from Schwing Bioset Inc. (Somerset, Wis.), cake can either be routed directly to incineration or sent to a pair of storage silos. Once in the silos, the material is available for truck loading and transport, either to an existing composting operation or directly to the landfill.

Change they can use

Centrifuges installed several years before the expansion successfully handle the increased flows to the solids handling area, according to Jeff Hall, assistant plant manager.

“That upgrade was implemented both to replace aging equipment, as in the case of the centrifuges, and to add functionality to other areas, like the transportation of solids,” Hall said. “In the past, primary solids were gravity-thickened while older centrifuges thickened the waste activated sludge [WAS]. The new units now thicken both the primary solids and the WAS. This new approach boosts the solids content of the resulting dewatered cake to about 20% to 25%, a nice improvement over the 17% to 21% solids content with the older system.”

Additional changes included installation of new cake pumps, a pair of storage silos, and sliding frames at two points in the solids handling process.

The routes to disposal

Southerly’s pumps and silos assist in transporting cake to several disposal options. As material exits the centrifuges, it is routed to any of four KSP 45V(HD)L-SFMS pumps, which route it either directly to the incinerators or to storage silos.

“Even though incineration is the most efficient method of disposal, we still try to keep the compost operation fed with as much as it needs, since that is the better use of the product,” said Carmon Allen, solids supervisor 2 at Southerly. The solids pumps at Southerly are designed to generate a force sufficient to move cake the long distances needed for either incineration or storage. It is approximately 91 m (300 ft) to the multihearth incinerators, which have operating temperatures of 760°C (1400°F), and about 122 m (400 ft) to the storage silos, Allen said. Equipped with a solids-flow measuring system, the pumps are able to measure to within 5% the amount of solids that are pumped to the incinerator. This simplifies the plant’s U.S. Environmental Protection Agency reporting requirements for the incinerator.

“Material headed to the silos, however, has an additional challenge to overcome,” Allen said. Once it reaches the base of the silo, “the cake has to go straight up another 100 ft [30 m] to enter the top of the structures, so the force needed to do that is really pretty impressive. I don’t think any regular equipment would be up to a task like that; these are definitely the right pumps for the job.”

Giving it the slip

Despite maximum operating pressures of 7585 kPa (1100 lb/in.2) for each pump, the extended distances at Southerly prompted Schwing Bioset to make accommodations to help move the solids along. The company added a pipeline lubrication system with a 360-degree annular groove that evenly injects a thin film of water around the entire annulus of the pipe. The water separates viscous and sticky materials from the inner wall of the pipeline. This reduces friction loss in the pipeline and lowers pipeline operating pressures by as much as 50%. This lubrication also means less energy use to move the solids and less wear on parts.

Parts such as the pumping rams, poppet valve discs, and seats are lasting for 6 months, said Tom Thomas, maintenance supervisor 2 at Southerly. “That’s about 4000 hours of wear-part life, which is outstanding, given what they’re being asked to pump.”

Silo efficiency

Prior to the installation of its two silos, Southerly relied upon a smaller holding vessel, a belt-fed, hopper-equipped component that used a series of screws to load trucks sitting under the discharge chute. City officials say the new silos are larger — providing about 75% more capacity — as well as far more efficient.

The new silos can load a truck in 5 minutes instead of the 45 minutes that was required before. Because the city pays a contractor to haul biosolids, reducing loading times lowers overall hauling costs. Trucks now spend more time hauling and less time waiting to be loaded. This means more trucks are loaded per day at a lower cost.

Inside the sliding-frame silo, hydraulic cylinders move an elliptical frame across the silo floor. The frame’s action not only breaks any bridging that can occur above the extraction screw, but it also pushes and pulls material toward the silo center for discharge. The cake then is fed into a twin screw feeder for discharge into trucks.

“Each silo holds better than 1500 tons [1360 Mg] of cake, so even if one of the incinerators went down and there was an interruption in the trucking operation, we’d still have a nice short-term storage option while things get back up again,” Allen said. “It’s really all about flexibility, and these silos afford us that.”

Due to the sheer size of the silos, each is equipped with three extraction screw conveyors at the bottom, enabling the trucks to be evenly loaded without having to be moved back and forth.

The silos also include an odor- and splash-control shroud that minimizes the need for odor control in the truck-loading building, reduces the chance of material splatter during loading, and confines any splatter to the area immediately adjacent to the trucks.

After loading, the solids are hauled either to a landfill or the composting operation. “Today, we are reusing about one-third of the solids we handle through the composting operation,” Hall said. “We are generating revenue from a product that was once simply discarded. However, it is also a plus from an environmental perspective. Any time you can reuse something rather than just burying it or burning it, you are making a positive impact.”

©2012 Water Environment Federation. All rights reserved.

Tags: Piston Pumps, Biosolids, Wastewater Treatment

USEPA PEC Committee Grants PFRP Approval to the Bioset System

The USEPA PEC Committee Grants Nationwide PFRP Approval to Schwing Bioset and Its Class 'A' Biosolids Process known as the Bioset System

After extensive testing and research, Schwing Bioset is proud to announce that the USEPA has given nationwide approval to the Bioset Process to reduce its operating temperatures from 70°C (158°F) to 55°C (131°F) as a Process to Further Reduce Pathogens (PFRP). Operating at 55°C (131°F) results in a greater than 20% reduction in operating costs for owners of the Bioset process.

Somerset, WI 2011

After extensive testing and research, Schwing Bioset is proud to announce that the USEPA has given nationwide approval to the Bioset Process to reduce its operating temperatures from 70°C (158°F) to 55°C (131°F) as a Process to Further Reduce Pathogens (PFRP). Operating at 55°C (131°F) results in a greater than 20% reduction in operating costs for owners of the Bioset process. Prior to receiving nationwide approval, site-specific approval at one site in Texas had been granted.

The Schwing Bioset Process is a technology that continuously converts municipal biosolids into a Class A/EQ saleable product in full compliance with 40 CFR Part 503 Rule. The process mixes dewatered biosolids with calcium oxide (quicklime) and sulfamic acid (solid granular acid) and continuously pumps it into a plug flow reactor. The Schwing Bioset Process currently meets Class ‘A’ standards via pasteurization at 70°C for 30 minutes, and vector attraction reduction by maintaining an elevated pH.

At the elevated pH levels, ammonium contained within the biosolids evolves as ammonia, and the ammonia is maintained in solution with the biosolids in the pressurized plug flow reactor. Miscible contact of the ammonia with the biosolids enhances pathogen destruction to Class A/EQ standards at lower temperatures. Mixing is accomplished with Schwing Bioset’s twin-screw feeder and the blended material is pumped into the plug flow reactor with Schwing Bioset’s twin- cylinder positive displacement piston pump.

The combination of high temperature, high pH and the biocidal effects of ammonia ensure that the biosolids are pathogen free in accordance with Class A/EQ requirements. The end product is characterized as a lime enhanced soil amendment and is a valuable product for numerous land application markets. Because the Calcium in the Class A/EQ end product is readily available, soil pH adjustment occurs in less than half the time of what typical agricultural lime products require. An additional benefit of the end product is that the high percentage of organic content (35-55%) returns organic material to depleted soils.


Tags: Class 'A' Biosolids, Piston Pumps, Bioset System, Municipal Biosolids, Class 'A' Materials, Screw Feeders, Biosolids

Wastewater Treatment: London, Ontario

The London Greenway Pollution Control Centre ("Greenway" for short) is the main wastewater treatment facility for the city of London, Ontario. Greenway is an activated sludge plant that also receives liquid sludge trucked in from the city's other five wastewater plants. 

new Greenway small

Greenway dewaters the sludge and relies on a fluid bed incinerator. In 2008, the incinerator required shutdown for major overhaul that would last over three months. The city's Wastewater and Solid Waste departments are separate entities and are required to charge each other for services rendered. After determining that a prolonged incinerator shutdown would have a prohibitive cost, the Wastewater Department sought alternatives.

Schwing Bioset piston pumps were previously installed at the Greenway plant to feed the dewatered sludge to the incinerator, so plant personnel were knowledgeable about Schwing Bioset capabilities. The Bioset process was proposed to treat the dewatered sludge to beneficially reuse the biosolids as landfill cover. Representatives from the Wastewater and Solid Waste departments visited Bioset installations in Florida to observe the process and it was determined the end product would be acceptable as landfill cover at a preferable cost.

A change order was issued to the incinerator rehabilitation contractor to install the Bioset process equipment as a back-up sludge treatment train to the incinerator. The component equipment permits flexibility in the layout design that allowed the plant to use distinct idle spaces so that no new structures were needed to accommodate the installation.

The plant processed 25,000 metric tons of Bioset product between August and December 2008 while incinerator rehabilitation work was completed. The city has since returned to incinerating the biosolids, but maintains the Bioset equipment as a back-up for annual shut-down/rehabilitation work.

Tags: Bioset Process, Piston Pumps, Wastewater Treatment

Six Piston Pumps installed at L.A. Waste Water Treatment Plant

Schwing Bioset Finalizes Installation of Six Piston Pumps at Hyperion Waste Water Treatment Plant (WWTP) in Los Angeles, California Without Interrupting Existing Operations.
Somerset, WI, August 10th, 2009 --- Schwing Bioset (USA), Inc. announces they are in the final stages of installing six KSP 50V(HD)XL Cake Pumps with SD 500 Screw Feeders at the Hyperion Waste Water Treatment Plan In Los Angeles, CA.
In August of 2007 Schwing Bioset was given a Notice to Proceed to construct the six KSP 50V(HD)XL Cake Pumps with SD500 Screw Feeders to replace competitive equipment that was in place. Installation of the replacement equipment had to be completed without interrupting plant operations, which required a phased installation and equipment-commissioning schedule. As of August 2009 all of the equipment was on site and being installed and commissioned.

In 1996 the City of Los Angeles competitively bid six large piston pumps each for conveying 100 gpm of biosolids at the Hyperion WWTP.  The biosolids are dewatered to an average of 32% dry solids content with required operating pressures up to 1,200 psi.  Whereas, Schwing Bioset, Inc. was not the low bidder, we were not awarded the contract.

The city experienced perpetual issues with the reliability of the pumps supplied by the low bidder affecting their ability to operate on their desired schedule.  After several unsuccessful years of trying to work out the issues with the low cost bidders equipment, the plant made the decision to abandon that equipment and replace it with equipment manufactured by Schwing Bioset. 

Dave Taylor, Senior Wastewater Treatment Operator, adds, “The confidence in the Schwing product has been illustrated by the field work performed by these Schwing team mates here at Hyperion."

About Schwing Bioset, Inc.

Schwing Biosets mission is simple, to become the market leader in the biosolids and beneficial reuse industry.  Their team of professionals has the skill and experience necessary to develop material handling solutions tailored toward the specific needs of their customers.

Please direct all media inquiries to Chuck Wanstrom, National Sales Manager, please e-mail 
wastewater pump

Tags: Piston Pumps, Biosolids, Wastewater Treatment