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Date: 4 / 5 /2007
ABB
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News Release
City in Kansas moves toward more efficient wastewater processing, service
With 450 miles of sanitary sewer-collection lines and 33 lift stations that feed into a central wastewater treatment plant, the City of Lawrence, Kan., wastewater management system is extensive. The city has been recognized as one of only two in the nation that have three environmental management certifications for wastewater operations. These certifications demonstrate the city's ability to provide customers with an efficient level of service, while maintaining a high standard of environmental protection.
Because of ongoing increases in demand, Dave King, wastewater maintenance manager, City of Lawrence, is continually looking for ways to improve efficiency. He explains that lift station number 16, built in 1958 and located close to downtown Lawrence, is responsible for transporting approximately 600 million gallons of dry weather-flow a year, about 25-30percent of the city's wastewater usage. The combination of aging equipment and increasing flow from new residential developments led to the decision to retrofit the station completely in the spring of 2006. King turned to the city's long-time PLC supplier, Logic, Inc. to help develop a solution.
An ABB distributor since 1997, Logic recommended installing ACS800 drives on each of four new 125HP pump motors, to: increase efficiency and power factor to improve electricity cost savings; extend the life of the motors and reduce repair costs; and minimize or eliminate an addition of harmonics that can interfere with instrumentation and overheat feeder breakers and transformers.
ABB Drives Ensure Constant Flow
When wastewater enters a lift station, it initially goes through a course screening process, which removes solid particles that might cause damage to the pumps. The wastewater then flows into an enclosed wet well, which can be 30-40 feet deep. Sensors monitor the depth of the wastewater in the wet well. Pumps are used to displace the wastewater from the well to the treatment facility. Drives often play a key role in supporting the pump operation, ensuring that a constant flow is discharged to maintain optimum wastewater levels.
By controlling pump speed, an optimum level can be maintained that ensures constant flow between what's coming in and what needs to be pumped out, says King. Installing the ABB drives has enabled us to eliminate unnecessary pump starts.
He adds: ABB drives give us the ability to handle the wide range of variations in wastewater flow entering the station due to time of day, time of year and weather conditions, as well as the capacity to accommodate future growth. The fact that we can now pump wastewater out at the same rate it enters also helps us reduce odors.
ABB Drives Offer Turkey Solutions - Easy Installation
King was impressed with ABB because of its ability to offer turnkey solutions direct from the factory. "We required certain features in the cabinet, such as a by-pass, fuse disconnect, remote I/O and selector switches. ABB was able to provide all that from a factory service center," he says. Since the lift station fits in a 900 square-foot space, theACS800's compact footprint fit well into the facility.
Since the drives were shipped with all of the specifications pre-installed, installation was a smooth and easy process. To maintain constant uptime during the retrofit, two pumps were taken off-line at a time, keeping the other two pumps running.
ABB, Automation Products, Low Voltage Drives, is the world's largest manufacturer of electric motors and drives. In the USA, an integrated channel of sales representatives, distributors, and system integrators allow ABB, New Berlin, Wis., to supply a complete line of energy-efficient electric drives, motors and engineered drive systems to a wide range of industrial and commercial customers. Products manufactured include AC and DC variable speed drives for electric motors from 1/8ththrough 135,000 HP, and application-specific drive system solutions to meet diverse customer needs (http://www.abb.us/drives).
ABB (www.abb.com) is a leader in power and automation technologies that enable utility and industry customers to improve their performance while lowering environmental impact. The ABB Group of companies operates in around 100 countries and employs about 108,000 people.
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