When Mark Green, P.E., joined the Topeka, Kan., Water Pollution Control Division (WPCD) as superintendent in the fall of 1998, he had the important task of reviewing an existing Capital Improvement Plan (CIP) for the city's municipal wastewater system. One particular recommendation within the CIP concerned an existing pump station that served the city's North Topeka Treatment Plant.
Installed in 1969, this underground influent pump station had served the north side of town for nearly 30 years. It featured three 8-inch pumps each with an average design capacity of 1750 GPM at 42 ft. TDH. According to the CIP, the station was scheduled to be replaced with a new pump station, including a new pump building, at a price tag ranging from $4 million to $6 million.
Before approving the project, Green invited his maintenance and pump station supervisors to discuss the current condition of the pumps and station, which was manufactured by Smith & Loveless Inc. Included in this group was Bert Dechand, Supervisor III for the Topeka WPCD and a 27-year veteran of the department. Dechand, who oversees maintenance for the city's wastewater treatment plant operations, and his staff suggested to Green that the pumps were operating fine and there were no signs of impending failure.
"The pumps in the station had performed well," said Dechand, noting that routine maintenance had been performed throughout their service life.
Smith & Loveless, originator of the factory-built pump station concept, conducted a thorough review of the station at the request of the city. A few specific recommendations were offered, including upgrading cathodic protection and touching up areas with epoxy paint coating, but overall the review concluded that the pump station was in good shape.
An ultrasonic test was used to measure the structural integrity of the station's metallic shell to determine if there were any weak structural areas in the station that would require anything from simple repair work to complete replacement. The testing revealed that the station's metal thickness throughout both the station shell and entrance tube was very near the original thickness of the station.
The report as a whole confirmed what Dechand and others had originally reported to Green: the pump station was in proper working order after 30 years of service.
"We don't have any problems with the station," said Green. "And I was pleased with the tech support in analyzing the structure of the station and the operation of the pumps. This can be of benefit to cities with similar situations."
Dechand agreed. "It just wouldn't have been cost-effective to replace the pumps," he said. "We're expecting to get a lot more life out of that station."
By determining that the station would provide reliable service for many more years, the city of Topeka WPCD was able to save millions of dollars of unnecessary investment.
"We were able to take that money in the CIP and utilize it for more critical repairs elsewhere," said Dechand.
