The average citizen in the modern world consumes around 34 gallons (130 liters) of household water every day—and most of it is contaminated because we use it for cleaning, washing clothes, showering, or flushing the toilet. The manufacturing sector also consumes a lot of water—and in addition a large quantity of rainwater is ducted to the wastewater treatment plant via the sewers. Enormous amounts of water therefore have to be treated every day to keep streams, lakes and the sea clean.
For wastewater professionals, a common difference heard between industrial wastewater plants and municipal plants is that one exists for profit, the other for necessity. In both cases, however, reliable and efficient pumping systems are a must. One of the keys to a good pumping system is a good design: placing quality components where they are needed. With voluminous experience with a diverse client base, Landia has positioned itself to assess any pump user’s needs and prescribe the right component from their products. Landia has supplied equipment to public and private water treatment plants since the 1980s, and has gained practical experience from small and large plants throughout the world.
Two recent success stories highlight the constraints and demands placed on wastewater professionals around the globe, and the need for designed solutions. The following case studies—one from North America, one from Europe—are representative of issues facing wastewater treatment facilities for public and private concerns, and also illustrate the benefits a global pump manufacturer like Landia can provide from their varied experiences.
CASE 1: GENTLY DOES IT WITH NOCTURNAL PUMPS
While workers from a landmark building in Canada are at home sleeping, Landia’s pumping and mixing equipment quietly goes to work removing highly concentrated sewage at a flow rate of just 0.58 gallons (2.2 liters) per second from an 8189 gallon (31,000 liter) cistern.
In fact, due to a lack of existing sewage capacity, the authorities in this city could only allow the prestigious seven-storey CAD $100 million building to go ahead if such an overnight wastewater removal system could be put securely into place.
The initial standard propeller mixer was constantly fouling and tripping on overload and was also causing foaming, which worsened the unwanted surface matt build-up.
Supplied by Engineered Pump Systems of Port Coquitlam, who have worked in close conjunction with Landia and professional services firm WSP to bring about the most effective low-flow design, Landia’s chopper pumps and mixers are in operation from 11pm until 6am, removing sewage from the cistern that serves the third to seventh floors.
Eric C. Pettit, P.Eng, project manager for WSP, provided consulting services through for the project. “To meet the strict low-flow rate of just 0.58 gallons (2.2 liters) per second that was required for the overnight time slot, we’ve had to throttle the Landia pumps down substantially with a variable frequency drive (VFD) as part of this complex installation. We start the pumps at 100 percent speed, and then ramp them down to the restrictive flow rate. We then ramp them back up to 100 percent just before shut-off to ensure that the pump is clear.”
The additional Landia unit pumps into a manifold to create a spray action along the floor of the basin, moving any settled material to the pump suction area.
“We are also using an additional Landia chopper pump as a mixer. Initially a standard propeller mixer was used, but it was constantly fouling and tripping on overload due to high concentrations of sanitary products that were causing a floating matt problem,” Pettit adds.
“It was also causing foaming, which worsened the unwanted surface matt build-up. We use the additional Landia unit to pump up and into a manifold so as to create a spray action along the floor of the basin, moving any settled material to the pump suction area. This also pre-chops the materials, effectively eliminating the chances of jamming when we are running the VFD-controlled pumps to discharge.”
“This has been an unusual, challenging yet very rewarding project,” adds Earl Masse for Engineered Pump Systems. “The Landia chopper pumps have conclusively proved their non-blocking capability and their ultra-reliability. The specification of a good pumping system to the successful operation of this new building has been crucial.”
CASE 2: THE RIGHT BLEND AT TULLAMORE
Landia’s externally-mounted GasMix digester mixing system is proving to be an integral part of EPS Water’s successful design-build-operate (DBO) package at the recently expanded wastewater treatment works in Tullamore, home of the celebrated Irish whiskey, Tullamore Dew.
EPS Water’s process for the wastewater treatment works, which caters for a population equivalent (PE) of 45,000 and a sludge treatment capacity of 80,000 PE, includes two sludge digesters with duty/stand-by CHP, sludge holding tanks, sludge drier and all associated works.
Tullamore Wastewater Treatment Works
A leader in infrastructure support services, including design and build for the water sector, EPS Water introduced Landia’s GasMix for its reliability, gas yield enhancement and easy maintenance.
“For our client, Irish Water, Landia’s GasMix not only produces more methane than other systems, but it does so much quicker because it mixes the whole tank properly, leaving no crust on the surface,” EPS Regional Operation Manager Gerald Buckley explains.
Landia’s externally mounted GasMix AD digester mixing at Tullamore Wastewater Treatment Works.
“We have found the GasMix unit to be extremely reliable. Easy access to the pumps ensures staff carry out routine maintenance efficiently and safely, thereby avoiding downtime,” Buckley adds. “At EPS we deliver mission-critical products for the very best, long-term technical solutions—and Landia’s GasMix meets that requirement as a system we know can rely upon for its efficiency and performance.”
About The Author
Soren Rasmussen is the director of Landia, Inc. For more information Landia’s range of applications, call 919.466.0603, email info@landiainc.com, or visit www.landiaworld.com.
MODERN PUMPING TODAY, January 2015
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