Case Studies - Biosolids Management and Headworks

Case Studies - Biosolids Management and Headworks

Submersible chopper pump stands strong through tropical storm

Cleaning system eliminates biomass, increases productivity

Problem: Shane Donoghue, a wastewater facilities manager in a large Australian city, saw accumulation of FOG and biomass up to 4 feet deep in a month in a lift station. This required tens of thousands of dollars in maintenance, including weekly to biweekly vacuum truck service and confined-space entry to clean the well by hand. “Sometimes the FOG would build so thick, it was too great of a load for a single truck,” Donoghue says.

Solution: Donoghue purchased the EP-1300 conditioning and cleaning system from Anue Water Technologies. The unit operates by recycling a small amount of discharged flow to create ongoing surface agitation that prevents FOG buildup and promotes aerobic activity.

Result: The installation immediately reduced maintenance checkups from weekly to monthly. The lift station no longer required frequent vacuuming, and confined-space entry was nearly eliminated. The unit saved $15,000 in the first year and nearly $22,000 in the second year on labor, vacuum truck services and landfill tipping fees. Maintenance costs declined by nearly 50 percent. 760-727-2683;

Septage receiving stations secure water and wastewater utility

Problem: The Anchorage (Alaska) Water and Wastewater Utility had two septage receiving facilities guarded only by a gate access system. There was no way to record what haulers were dumping at either site, and a 25-mile trip to the facilities from the administration office made sampling visits time-consuming.

Solution: The utility installed a Portalogic DS-200 Septage Receiving Station from EleMech at each facility. The systems are monitored remotely by Portalogic Management Software. The customized stations are insulated and have heavy-duty heaters. Proximity card readers and keypads are used to access the gate-secured area. Native gate control capabilities are integrated with the gate access system, providing backup. EleMech trained utility personnel on the stations and software. 

Result: Administrative personnel can see when a hauler opens the gate and when either station is in use. The stations automatically sample each load, track volume and hauler information, and sync that data with software on the office PCs. The utility now can charge haulers by volume, eliminating cheating. 630-499-7080;

Mixing panels keep grit removal system running

Problem: The Southport Advanced Wastewater Treatment Plant in Indianapolis sought to prevent buildup in its grit removal system for a dry-weather flow of 70 mgd. “The pulsed air mixing system is provided in Junction Structure 101B to suspend solids, which settle out following grit removal so they can pass on downstream for further removal or treatment,” says Gary Ruston, senior project engineer. “Keeping solids from accumulating will minimize or eliminate the need to periodically take the structure out of service for cleaning.”

Solution: Wessler Engineering worked with Pulsed Hydraulics to provide 24 bubble-forming plates in the channels and basin. The company supplied three four-valve mixing panels with an Allen-Bradley PLC (Rockwell Automation) and two 20 hp rotary screw compressors. “The pulsed air system was selected due to its higher mixing energy and better ability to keep or resuspend solids throughout the tank,” Ruston says.

Result: The requirements were met and verified by the customer’s engineer. “The system can be operated on a continuous basis or intermittently, based on operator preference,” Ruston says. 800-641-1726;

Headworks screen successfully removes wet wipes 

Problem: Up until 2007, the Glenbard Wastewater Treatment Plant in Glen Ellyn, Illinois, had outdated catenary screens that were too coarse and unable to collect any wipes; they were passing through the system and causing issues downstream.

Solution: The MS Bar Screen from Headworks International was installed in 2007, and Glenbard never experienced problems with wipes clogging its system. The bar screen is known for effectively screening out wipes. It has 3/16-inch bar spacing and the unit is suitable for fine screening and for removing solids from incoming wastewater, thus protecting downstream equipment.  

Result: To prove the screen’s effectiveness, Headworks International performed a test in the spring of 2016. Wipes were purchased at a nearby store, dyed fluorescent yellow, then fed into the sewer system at two points. Over 97 percent of wipes were recovered within 20 minutes. Moreover, the operators reported nothing of color showed up downstream. 713-647-6667;

Submersible chopper pump stands strong through tropical storm

Problem: The main lift station serving the wastewater treatment plant in Morgan’s Point, Texas, experienced problems with its three standard nonclog pumps. The pumps frequently clogged with shop rags, pieces of lumber, plastic bottles, gloves and wet wipes when rainfall reached or exceeded 2 inches. Over seven years, these issues required the city to spend $100,000 for pump maintenance and service.

Solution: The city installed a Vaughan SE-Series submersible chopper pump, along with a complete guide rail system to solve the problem.

Result: After the pumps were installed in July 2016, the city experienced more than 100 inches of rain with no plugging or other issues. During Hurricane Harvey in 2017, the pumps ran continuously for 72 hours without incident. “I just wish we had purchased these pumps years ago to eliminate the maintenance headaches we endured and the costs we incurred keeping our previous pumps in operation,” says Brian Schneider, city administrator. “If the former pumps were still installed, residents would have had sewage in their homes.” 888-249-2467;

City converts biosolids processing equipment after fire

Problem: The City of Northfield (Minnesota) Wastewater Treatment Plant (3 mgd design) produced Class A biosolids via an open alkaline and thermal stabilization process. In May 2018, a fire destroyed all of the Class A biosolids processing and the dewatering and odor control equipment. 

Solution: Rather than replace the old equipment, the city converted from belt presses to screw presses for its dewatering and purchased two machines from Schwing Bioset. The closed Schwing Bioset process contains odors and dust and does not require supplemental heat. It is approved by the U.S. EPA through the Process to Further Reduce Pathogens to operate at temperatures below those specified in the 503 regulations. 

Result: The plant is scheduled to be operational later in 2019. To help bridge the gap in biosolids processing while the new facility is built, the city rented a mobile screw press and Schwing Bioset trailer. 715-247-3433;

Centrifuge system decreases manpower, increases biosolids quality

Problem: Solvay, an advanced materials and specialty chemicals company in Willow Island, West Virginia, has five chemical plants that produce around 3 mgd of wastewater. Because the wastewater produced by chemical plants contains very few fibers, dewatering the biosolids was difficult. “We have a lot of batches that change day to day and month to month,” says Brian Smith, maintenance and wastewater treatment superintendent. “This makes it difficult to keep a healthy biomass.” Two old chamber presses could not always handle the demand.

Solution: Smith connected with Flottweg Separation Technology for a pilot program on a rental agreement for centrifuge equipment. The pilot unit originally came with a solid scroll, which was then exchanged for an open-bodied Xelletor scroll.

Result: Solvay saw an immediate improvement as the pilot unit produced biosolids at 19 to 20 percent solids. The centrifuge system allowed the company to reduce dewatering labor, reduce the volume sent to landfill, increase biosolids consistency and save energy. The plant saw a return on investment within a few months. After the first year, the system saved about $214,000. 859-448-2300;

Screening system saves company time and money

Problem: Aqua Engineers has served the water and wastewater needs of the Hawaiian Islands for 37 years. With limited space at sites served by the Oahu Wastewater System team, it was not feasible to build a drying bed for debris. This meant driving an hour to the available drying bed and then returning to clear out the bed after the material dried.

Solution: The Mega Screen from ScreenCo Systems allows the company to dewater and clean debris on site at one of its pump stations. 

Result: The screen has saved time and increased productivity, as it provides a quick and easy way to unload the Vactor vacuum truck. 208-790-8770;

Mixer provides efficiency and energy

Problem: The Bellozanne Sewage Treatment Works on the island of Jersey in the Channel Islands, a crown dependency of Great Britain, sought an energy-efficient mixer system.

Solution: An externally mounted GasMix system from Landia was installed, using a chopper pump to break down particles. “We agreed straightaway that for the three new anaerobic digesters, all pipework and moving parts should be on the outside of the tank,” says Michelle Macleod, principal mechanical engineer for Doosan Enpure, which delivers water, wastewater, and renewable energy solutions. “Externally mounted equipment would also improve health and safety by eliminating working at height and confined-space entry.” The plant team also chose Landia pumps for three tanks containing digested, thickened and unthickened biosolids.

Result: Dave Garnett, technical specialist for wastewater at Doosan Enpure, notes that Bellozanne is achieving about 60 percent volatile solids: “Good mixing is critical with the high temperature feed to the digesters to make sure that everything is distributed properly. GasMix is working very well because we’re seeing plenty of energy produced by the combined heat and power system, making a big reduction in operating expense.” 919-466-0603;  


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