Delware, OH, waste water treatment plant was looking for a solution to replace their conveyer system. Conveyers are costly and difficult to maintain due to the many moving parts. The operators at the plant got in contact with Buckeye Pumps, the local seepex distributor. After analyzing the problem, seepex and Buckeye Pumps engineers came to the conclusion that a seepex load cell controlled Progressive Cavity cake pump was the solution. When compared to a conveyer, the pump results in a $1,500 per square foot mean capital cost savings.

Delaware is a small Ohio town located about 30 miles north of Columbus, the state capital. The cities 34,000 residence will rely on a functioning water treatment system as they continue to growth over the next decades. Delaware retains its small town vibe while also offering the benefits of a major metropolis. Business is growing so the need for water treatment will have to grow with it.

The treatment plant in Delaware is responsible for all domestic and industrial wastewater from within the city along with the disposal of the sewage sludge produced during the wastewater treatment process. The expanded facility is capable of handling 10 million gallons per day. After the solids separation, the sludge is belt pressed to an approximate 30% solids content.

Previously, the dewatered sludge fell onto a conveyer which would transport the sludge into dump containers, which would later be hauled off to a landfill. The rectangular dump containers would frequently have to be moved with a front-loader to assure proper distribution of sludge. The conveyors were messy. Dewatered sludge would often fall onto the floor and require clean up. Oder was also a problem, making this a dirty job that Mike Rowe would even avoid.

Upkeep on the conveyor was tedious and expensive. Many moving parts mean that there is a higher chance of something breaking. It is impossible to stock all the parts needed to repair these and ordering replacements could take a long time and/or require an expedite fee.

Ken Miracle from Buckeye Pumps, a seepex distributor, worked closely with Dwight Miller and Gerald Glenn from the city of Delaware to configure the perfect solution. A seepex open hopper pump size 17-12 of the BTE design was installed. The 17-12 has a conveying capacity of 14 to 18 GPM. The BTE design pump can handle up to 35% dry solids contents. The feed screw moves the cake into the compression zone at a rate that is three times greater than the physical capacity of the pumping elements.  The high shear of the feed screw and circulation of the thixotropic sludge reduces the apparent viscosity, so it is easier and more efficient to pump. A custom hopper extension was installed for full containment of dewatered sludge coming from belt pressing. No more shovels.

This cake pump was fitted with load cell sensors. These sensors are integrated into a VFD and controlled by a seepex control panel. The speed of the pump is adjusted according to the weight within the pump hopper. Higher levels, speed increases, lower levels, the pump slows. This saves energy costs and increases the efficiency of the pump. The sludge is moved through 6 inch pipe to the dump containers. A serious of valves allows operators to evenly distribute the sludge within the containers without using heavy equipment. No more front loader. In this case, the dewatered cake travels through approximately 15 feet of pipe, however, many times this distance is much further. Fear not, seepex offers a fully integrated boundary layer injection system. Included are an injection ring and an MD metering pump.

Once installed, operators noticed that due to the length of the custom hopper, additional reinforcement was needed. seepex solved the problem and reinstalled the reinforced hopper shortly after. Dwight Miller says, “we are very happy with the performance of the seepex pump, trouble free.” Gerald Glenn says, “I’m glad these machines are working for us now, before it seemed we were doing all the work anyway.”

The pump has been running problem free for two years, with the only maintenance being a recent change of the stator. seepex had effectively contained odor, solved the dump container issue, reduced capital costs, and down time.

For more information, visit seepex.com