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Editorial from Water & Wastes Digest

On Pumps and Related Products

All of the features described in this article were made possible because of our software. The ISCO 4501 pump station flow monitor and Pumplink (a previous version of VOLUCALC 4) is a good datalogging system created and made by us and sold by ISCO. MerMaid add all the electrical analysis not available within VOLUCALC or any other datalogging system of this price.

Pump Station Monitor Keeps Village of Kohler On Top of Collection System

Bruce Neerhof at Village of Kohler's - Pump Station Monitor

Kohler, Wisc., a charming village of 1,900 residents near the shore of Lake Michigan north of Milwaukee, is perhaps best known as the home of the Kohler Company, a leading manufacturer of bathroom fixtures. The collection system in the Village of Kohler consists of 25 miles of sewers ranging from 8 in. to 42 in. in diameter, with more than 400 manholes and three lift stations.

The Sunset lift station uses two 7.5 hp pumps to serve a development with 21 homes that used to have septic systems, while the Sports Core station has two 10 hp pumps to serve a combination of residential and commercial development, including a shopping center, a fitness center, and convenience stores. The Fenwood location is the main lift station. with three 50 hp pumps that convey sewage to the 18 mgd wastewater treatment plant in nearby Sheboygan, Wisc.

Bruce Neerhof, public works superintendent for the Village of Kohler, uses 4501 Pump Station Monitors from Isco, Inc. in Lincoln, Neb., to stay on top of his collection system.

Principle of Operation

The Isco 4501 Pump Station Monitor monitors the operation of the pumps at the pump station as the wet well fills and is emptied. Combining this information with the known volume between the levels in the wet well, the 4501 uses patented algorithms to calculate the flow into and out of the pump station, and the pumping rate of each pump. By using drawdown calculations rather than manufacturers’ pump curves, influent flow and pump capacity at most pump stations can be measured within 1%.

Neerhof has Isco 4501s installed on each of his three lift stations. According to him, "In the past, we would record the numbers on the hour meters on the pumps on a regular basis, but they were never read at exactly the same time each day, so the data wasn’t that useful. We also did manual drawdown tests, but it was so time consuming that we could only do it every once in a while."

"But the 4501 is like having someone at each pump station conducting drawdown tests 24 hours a day. And, with all of the data reported on a 24 hour basis, midnight to midnight, if the flow at the main station is high, we can quickly see where it is coming from. It keeps you totally on top of what’s going on." The 4501 also eliminated the need to do a major engineering study. The Sports Core lift station, constructed in 1982, originally was intended to be a temporary station with a life of five to ten years. Eventually, it was to be replaced by an interceptor sewer, or the lift station was to he enlarged. It has now been operating for 15 years, and the Isco 4501 demonstrated that it has enough excess capacity to last another 10 to 15 years. This monitor also has helped the Village of Kohler discover an illegal sewer connection. Neerhof said, "The 4501 at the Sunset station occasionally measured a 500 gallon spike. That information helped us locate a residential sump pump that was connected to the sanitary sewer instead of the storm sewer."

Installation Ease

The 4501 can be installed in a matter of minutes. Its pump monitor inputs connect to anything from 12 to 120 volts AC or DC that turns on when the pumps are activated, such as indicator lights, pump timers, or pump motor starters. There is no need to shut down the operation of the pump station, and confined space entry is eliminated. In addition, it never needs calibration, and there are no level sensors to install. Its compact design and ease of installation make the 4501 ideal for portable use, or it can be quickly installed in the pump station control panel for permanent monitoring.

Expanded Monitoring Capabilities

The Village of Kohler has Isco 674 Rain Gauges connected to the 4501s at the Sunset and Sports Core lift stations. Little I&I was found in the collection system served by the Sport Core station. However, flooding previously was a problem at the Sunset station. By correlating rainfall and flow, the 4501 made it clear that I&I was the problem. Subsequent television inspections revealed a number of bad laterals. Once repairs have been completed, the 4501 will show the effectiveness of the repairs. This will he much less expensive than additional television inspections.

The Fenwood station also has a magmeter, and the 4 – 20mA output from the magmeter is connected to one of the 4501’s analog inputs. This allows the flow measured by the magmeter to be compared to the flow that the 4501 measured using its volumetric technique. Another 4501 logs the 4 – 20mA signal from the magmeter on the effluent from the Kohler Company’s manufacturing plant. "This allows all of our data to be presented in a consistent manner," said Neerhof.

Informative Data Analysis

Results can be viewed using the 4501’s keypad and display. In addition, the 4501 stores data on pump activity and other inputs in internal memory. Stored data can be retrieved on-site with a laptop computer or a removable memory card, or via an optional telephone modem. Isco Pumplink Software is then used to analyze stored data and generate informative graphs and reports on pump station flows and pump performance. "We have modems installed in all of our 4501s, and we call them every weekday and retrieve the data," Neerhof said in conclusion. "I also have Pumplink Software installed on my PC at home, so I can call them up during rainstorms in the middle of the night and on the weekend, and determine whether or not I need to respond immediately."

Detection of Abnormal Pump Activity

In addition to flow measurement, the Isco 4501 Pump Station Monitor detects abnormal pump activity so that preventative maintenance can be conducted before serious. expensive problems occur. This pump station monitor uncovered a bad alternator at the Sports Core station. This problem might have eventually been seen from the hour meters but, with the 4501 installed, the problem was immediately obvious. The Isco 4501 also reveals when a pump’s capacity drops, for instance, due to ragging or a piece of lumber jammed in the impeller. "The pumping rate may only drop by 20 GPM, so we wouldn’t see it without the 4501. But if we didn’t discover such problems, we would be wasting energy, and the plugging could become much more serious." Neerhof also likes the fact that the 4501 logs power failures at his lift stations, commenting that "The 4501 even verified that one of our pumps gained 15 GPM capacity after we rebuilt it."

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