Pumps, Lift Stations And Conveyance

Pumps, Lift Stations And Conveyance
City retrofits lift station wastewater pumps, slashes energy and maintenance costs

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City retrofits lift station wastewater pumps, slashes energy and maintenance costs

Problem: Harleyville, located 60 miles northwest of Charleston, South Carolina, needed to update its 25-year-old lift stations, which suffered frequent clogging and skyrocketing monthly utility bills related to extended pump runtimes. The reliability of the entire wastewater transfer system seemed to derail every three to six months, when a pump failed or a station backed up because the pumps were unable to keep up with demand.  

Solution: The town retrofitted three of these lift stations with energy-efficient Grundfos SLV wastewater pumps. To overcome prior difficulties with pumps clogging, the team selected the optional SuperVortex impeller to help ensure that solids up to 3 inches in diameter pass freely through the solids-handling pump without jamming.  

Result: The project reduced energy use by 35 percent and cut $25,000 in annual maintenance and repair expenditures. Peak pump operation time fell 80 percent from an average of 18 to three and a half hours per day. “There are zero maintenance costs or issues with the new pumps,” says Harleyville Maintenance Superintendent Tommy Weeks. “I chuckle each time the repairman, who was accustomed to a significant amount of business from us, calls to ask when we think one of the pumps will be in for repair.” 800/921-7867; http://us.grundfos.com.

Electric pumps equal big savings for sewer bypasses

Problem: Aging sewer infrastructure at a large municipality in North Carolina triggered one of the largest bypass projects in the state’s history to rehabilitate the failing lines. Flows totaling 74 mgd from a 76-inch influent line and a 54-inch diversion line needed to be bypassed into the two narrow doors on the treatment plant’s bar screen building, which separates out the large solids and debris prior to treatment. 

Solution: Rain for Rent calculated the figures using four electric DV 800c skid-mounted 16-inch pumps for the majority of the bypass. The company designed dual bypass systems to accommodate the flows. The first system handled 57 mgd through two 24-inch HDPE pipelines traveling 800 feet into each door of the building. The second 17 mgd bypass used 18-inch HDPE next to the 24-inch lines, which also ran into the building from the suction pit 600 feet away. All treatment plant operations ran normally without interruption during the bypass. 

Result: The city was able to complete the project a month early due to the efficiency of the bypass, realizing even more cost savings. During the four-week project, the Rain for Rent crew operated safely during the 1,800 man-hours of on-site work. This solution saved the municipality in excess of $100,000 in construction costs. 800/742-7246; www.rainforrent.com

City uses custom control valve to fix watershed environmental issue 

Problem: Bull Run Watershed provides water to Portland, Oregon, while also feeding the Sandy and Lower Columbian rivers below. The river temperature became too warm for some of the fish species to spawn. Conservation authorities requested the problem be fixed. 

Solution: City officials decided to alter the source from the dam that feeds the lower rivers, from the warmer top layer to the cooler waters in the deep part of the dam. To make this happen, they needed a valve that could handle flow differential from low up to 83,000 gpm and pressure differentials from 45 to 0 psi. Two S106-2SC-PCO-MV-C-AC valves from Singer Valve were installed, with an MCP-TP Control Panel. The valves were fitted with an anti-cav system to deal with large pressure drops and a single rolling diaphragm (SRD) to provide smooth flow regardless of the flow variance. 

Result: The 24- and 36-inch valves were set to run in parallel with dual solenoids in the pilot system, which allows the MCP-TP to control the valves individually and modulate the desired valve to the required setpoints electronically. With the anti-cav and SRD, the valve provides a stable solution that helps manage the river temperature so that the fish have the ideal temperature to recover. 604/594-5404; www.singervalve.com


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