Retractable tank covers minimize odor threats from plant expansion

Geomembrane Technologies Inc. (GTI) partnered with a large wastewater treatment plant in the U.S. for an impressive cover project. The plant was expanding its treatment capacity, which introduced odor threats. It needed an innovative cover solution that would address foul odors without hindering access for maintenance and sampling.

GTI custom-designed and supplied 49 structurally supported covers: 24 for its primary clarifiers, nine for its launder tanks, and 16 for its equalization tanks. These tanks are part of the early stages of wastewater treatment when odors are most intense, so it is crucial that the tanks be securely covered.

The retractable covers have successfully minimized odors as intended, helping reduce complaints. Plant workers can still perform their regular duties by simply retracting the covers.

Related: Case Study: Case Studies

City uses piston pumps in Class AA process

Problem: The dewatering facility at the Conserv II wastewater treatment plant in Orlando, Florida, had four belt filter presses and a series of belt conveyors that transferred the dewatered biosolids to trucks. The city wanted to move away from the belt conveyor system to reduce odors and maintenance issues, and make the process more operator-friendly.

Solution: Schwing Bioset offered a process to convert biosolids to a commercial fertilizer product. City staff members were impressed with the simplicity of the process after visits to several Bioset operations. A KSP 25 piston pump was added at the end of each belt conveyor to transfer the cake to the Bioset lime stabilization process, which uses a third KSP 25 pump to blend the materials. The end product is then pumped into a plug flow reactor and ultimately out to two truck loading areas.

Result: The pumps are programmed to work together to make sure that a consistent flow of biosolids can be treated to Class A status through the reactor. 715/247-3433; www.schwingbioset.com.

Related: Cover and Liner Systems Designed to Meet Your Needs

Relief valve with surge anticipator eliminates pipe breakage

Problem: The District of Central Saanich in Victoria, British Columbia, has a wastewater collections system with multiple lift stations. When fluids travel long distances, there is potential for pressure buildups from even slight changes in velocity. Hard stops at the pump or power interruptions can cause surges that blow lines out of the ground.

Solution: Singer Valve’s Pneumatic Dynamic Lifter (PDL) with surge anticipator was installed to reduce stress on the pipes and prevent surge damage. The compact relief valve can handle 200 psi and uses standard plant air to hold the valve closed. The chamber is fitted with a relief pilot that is also normally closed so long as the line pressure is lower than the setpoint. If the pressure rises above the setpoint, the relief pilot opens, causing the air in the cylinder to vent, which in turn opens the valve.

 Result: The unit was effective. When a surge returns to the pump, it comes back not to a closed system where it can cause damage but to an open valve where it can discharge safely into the storage well under the pump. 888/764-7858; www.singervalve.com.

Related: Top Performer - Plant: Lessons Learned

California resort wipes out pump clog problems

Problem: The resort community of Big Bear City, California, had weekly pump clogs at its pump stations because of consumer flushables. “Nine times out of 10 when we pulled a pump it would be clogged with rags,” says Andy Keller, sewer department foreman. Contributing to the problem, the resort’s population quadrupled on many weekends. Pump clogs often came in succession and on weekends, requiring overtime pay for workers.

Solution: The city purchased X-PELLER Impellers from Smith & Loveless for three problematic stations. The mono-port impeller design helps to counterbalance hydraulic forces and create a balanced, single flow path that passes 3-inch solids and problem flushables.

Result: With fewer pumps to unclog, operation costs have been reduced. Workers are freed up to service other equipment and are safer with no more trips to the confined space of an underground station. Pump clogs have been nearly eliminated, according to Keller. 800/898-9122; www.smithandloveless.com.

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Use Eductors to Effectively and Affordably Treat Your Wastewater

Wastewater treatment has become an issue in the chemical and petroleum industry. As a result it is imperative to find solutions for the reuse or dumping of generated wastewater. In order to reuse or properly dump wastewater, the water must be maintained to have a pH balance of 7. Caustic and acidic additives are added to wastewater to ensure this, and with the help of proper blending, wastewater can become neutral in no time.

Whether you are pH balancing wastewater in a tank or in a basin, tank liquid agitators (TLAs) can provide the mixing efficiency required to blend and balance wastewater in a timely matter. Computational fluid dynamic software can be used to show the placement, quantity, and pitch of the TLAs based on customer specifications to prove the blending results.

With questions, please email Eductor Sales Specialist Clarence Dela Vega at cdelavega@clark-reliance.com, or call 440/846-7653. To download the white paper, go to www.jacoby-tarbox.com/wastewater.

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