Johnson County Wastewater Forges Ahead

From the creation of their first sewer district in 1945 to over 1,207 sewer districts today, Johnson County Wastewater (JCW) (Overland Park, Kansas) has kept pace with the wastewater requirements of this rapidly growing community. JCW currently serves 500,000 customers and maintains over 1,700 miles of sewer line. This progressive organizationâs primary goal is to safely and efficiently transport and treat wastewater before returning it to an area waterway. Their success is based on their commitment to protect area waterways from pollution that can be caused by improperly handled wastewater.

The Operations & Maintenance (O&M) Division of JCW has the responsibility for clean water standards as well as providing operations and maintenance expertise that allows for the proper operation of the its collection systems, pump stations and treatment facilities. The efficient operation of each facility is dependent upon accurate and reliable flow data provided by instruments either located within the facility itself or located at remote monitoring sites. O&M personnel require instrumentation they can count on day in and day out for the successful operation of the entire system.

Stuart Garmon, Instrumentation Technician for JCW, is responsible for the maintenance and operation of equipment at several JCW facilities in the county. Garmon, a veteran of the wastewater field for over 18 years, is very familiar with the rigors of monitoring flow in the rugged wastewater environment. Challenges such as equipment durability and data accuracy top his list of must-haves!

For many years, Marsh-McBirneyâs local rep firm, Alpha Supply Company, has worked closely with the JCW team to ensure that they are kept abreast of new flowmeter technologies and product offerings that can meet their ever increasing demands and challenges. So, when JCW needed to monitor the flow of a 36ä storm bypass line that at times exceeded 50 MGD, the MMI Flo-System Model 253 open channel meter was selected for the task.  According to Garmon, 'We get a lot of debris down through there. I donât just mean typical wastewater. I am talking about logs, bricks, rocks and just about anything else you can imagine. There is a steel gate flapper valve that probably weighs 500 pounds and when that flow is going through it is sticking straight out. The Marsh-McBirney sensor and band just hang in there and donât budge. It is unbelievable!ä

The Flo-System Model 253 is an AC powered open channel flowmeter that was designed for long-term monitoring applications. The sensor utilizes proven electromagnetic sensing technology based on the Faraday principle and the 'Continuity Equation':

The measurement of both velocity and level in the same cross-section of pipe is critical for accurate flow rate determination, including surcharge conditions. The sensor is installed on a stainless steel mounting band and inserted into the open channel conduit. Mounting band selection is based on conduit size allowing for a snug fit. The Flo-System does not require expensive primary devices such as weirs and flumes that can potentially add thousands of dollars in construction costs to the project. The flowmeter is also capable of accurately monitoring reverse flows.

JCW also utilizes MMIâs insertable full pipe flowmeters to monitor their pump station flows. Three (3) Flo-System Model 283 flowmeters are installed on discharge lines at remote pump stations to monitor raw sewage flows. The Flo-System full pipe flowmeter also utilizes proven electromagnetic technology based on the Faraday principle. The sensorâs debris-shedding shape is ideal for wastewater flow applications. Because price is independent of pipe size, the Flo-System offers an attractive cost savings benefit when compared to traditional flowmeters whose costs go up as pipe size increases. The sensor is easily installed through a pipe hot-tap.

One of the full pipe flowmeters purchased by JCW replaced an existing spool-piece magmeter that encountered problems due to its originally installed location. 'We would have to shut down the station to get the spool-piece out for service. The station runs constantly. It was like trying to work on a car while it was still running.ä Garmon adds, 'The Marsh-McBirney sensor has the advantage of easy installation and removal. The sensors basically clean themselves and we never have any trouble with them. Calibration is also easy.ä  The two additional meters were ordered for new plant installations. They were also selected for their cost savings when compared with costs to instrument the lines with spool-piece magmeters, as well as their ease of installation in restrictive piping configurations which were encountered at the sites.

While JCW continues to successfully forge ahead as a progressive organization that applies principles of teamwork and employee involvement, MMI will remain by their side to ensure that they continuously receive accurate and reliable flow monitoring data they can count on for many years to come.