Metro WWTP Upgrades Piston Pump Sludge Flow Measurement System

Written by Chuck Wanstrom, March 2018

The Metro WWTP, operated by the Metropolitan Council of Environmental Services (MCES), located in St. Paul, MN, has an average daily flow of 215 million gallons per day (MGD) of incoming flow. Prior to 2004 the plant had been utilizing multi-hearth incinerators to burn their biosolids. A new incineration facility utilizing fluid bed technology was commissioned in 2004 and included a dewatered biosolids storage and feed system supplied by Schwing Bioset, Inc (SBI).

The feed system included four sliding frame silos providing intermediate storage of dewatered cake to provide a buffer in centrifuge and incinerator operations. Each of the four sliding frame silos were equipped with two KSP 45V(HD)L piston pumps to transport the dewatered cake to the incinerators. Each piston pump is equipped with a dual discharge to split the biosolids flow to multiple incinerator injection points, as well as a Sludge Flow Measuring System (SFMS) to measure within 5% the amount of biosolids being pumped into the incinerator. The SFMS is a critical piece of the operation as this is required to satisfy US EPA reporting requirements. This proven equipment configuration and flow measuring system has been utilized at numerous other facilities across North America for over 20 years.

Schwing Bioset has recently developed an improvement in its SFMS to reduce the possible sources of error that can be introduced with variations in pumping speed during operation. This next generation of SFMS results in an even more accurate means of recording and reporting biosolids flow and is further evidence of Schwing Bioset’s commitment to developing and improving its technology to better serve its family of customers. After nearly 15 years of reliable service, the Metro plant, and its continuing commitment to excellence, is currently in the process of performing upgrades throughout its Solids Management Building and is converting its piston pumps to this next generation of flow measurement. Schwing Bioset looks forward to many more years of supporting MCES and to the continued success of this impressive facility.

If you are currently using an SBI pump equipped with our SFMS and would like more information on upgrading your equipment to the latest generation of flow measurement, please contact us at (715) 247-3433 or schwingbioset.com/contact-us.