Submersible Shredder Pumps – BJM’s Answer for Wastewater Management at Sheraton Hotel In Denver, Colorado

Maintenance teams focus so much of their time and energy making sure equipment is running smoothly on a daily basis that they often do not have time to stop and consider opportunities that may exist to improve the efficiency of their day-today operations. About five years ago, one very proactive supervisor took the time, on top of his busy workload, to conduct extensive research that eventually enabled his company, the Sheraton Hotel, to upgrade their pumps. Dawit Anteneh, the Central Plant Stationary Engineers Supervisor, discovered BJM Pumps and then contacted Denver Industrial Pumps for support. Denver Industrial Pumps is an industrial equipment distributor and aftermarket service provider that has been supporting several industries in Colorado and Wyoming for the past 27 years.

Anteneh’s goal in searching for pumping solutions was to find new pumps that could operate reliably in the hotel’s wastewater collection system. The wastewater collection system at the downtown Denver Sheraton utilizes three waste water collection pits. Each pit had two vertical column pumps operating in a duplex arrangement; so when the primary pump would fail, the secondary back-up pump would start up.

“The vertical column pumps had been removed many times over the years. They were rusting out badly, and they were so old that they weren’t worth maintaining anymore,” explains Anteneh. “We really needed new pumps that would handle our waste water collection needs with lower maintenance than the old ones,” continues Anteneh.

Old Vertical Pump

Conducting an internet search, Anteneh first came across the BJM Pump line of submersible shredder pumps. After watching the videos and reading about the modern technology that these submersible shredder pumps offer, Anteneh contacted Phoenix Sullivan, an Outside Sales rep for Denver Industrial Pumps. Sullivan, who has provided many BJM Pumps to other end users over the years, considered Anteneh’s most important needs:

Easier Maintenance – vertical column pumps, which can be up to 15 feet long, can be very difficult to remove and install; especially in a hotel where access to this type of pumping equipment is typically located in very tiny spaces. The maintenance team needed a pump that would be easier to install and remove when maintenance was required.

Shredding capabilities – with the increased use of “flushable” wipes and other hygienic materials, the sewage entering the hotel’s wastewater collection pits is full of fibrous material. The old vertical column pumps were frequently being clogged with these solids, so the new pumps would have to be designed to handle solids in the wastewater.

Reduced downtime and improved pump reliability – nobody wants downtime. Downtime puts stress on the system, creates headaches for maintenance teams who often work overtime to solve the problem, and results in unplanned and unwanted expenses. It was critical to select pumping equipment that would operate reliably in the hotel’s wastewater collection system.

Sullivan worked with Ben Wells, Regional Manager at BJM Pumps, to find the best pump for the Sheraton’s wastewater collection system. Together, they selected the BJM SK110C-460T Submersible Shredder Pump, which can handle up to 3.5-inch solids at 845 gallons per minute with a maximum of 94 feet of head. When reviewing the SK110C-460T with Anteneh, Sullivan shared the following key qualities in his recommendation:

It’s Compact. The SK110C is about 2 feet tall, and because it is a submersible pump, the motor and wet end are one unit. Using this submersible pump would make it so much easier to install, remove, and maintain – saving the maintenance team a great deal of time and effort.

BJM Wastewater Shredder Pump

It’s Engineered to Shred Solids. The SK110C utilizes a cutting impeller with a Tungsten Carbide Tip to continuously rip apart solids against a tooth-edged spiral-shaped diffuser plate. With 360-degree shredding action and non-clog, single vane impellers, the SK110C would have the capacity to shred the wipes and fibrous materials that were being flushed through the hotel’s sewage system.

Motor Protection. Manufactured with an abrasion-resistant stainless steel motor housing, the SK110C is built with “Three Seal Motor Protection”. The motor is protected with double mechanical seals wherein the lower seal is made of silicon carbide / silicon carbide and the upper seal faces are made of carbon / ceramic. An additional lip seal is installed above the impeller to help prevent unwanted materials from entering the seal chamber. The SK110C also utilizes winding protection and (NEMA) Class F motor insulation, making it superior to pumps with Class A and B insulation because the (NEMA) Class F motor insulation allows the motor temperature to reach up to 230°F. If the temperature and/or amp draw becomes too high, an automatic switch turns the pump motor off. The switch automatically resets when

the motor cools, and the pump resumes operation.

After reviewing the pump specs and other details, Anteneh decided to purchase one of the BJM SK110C-460T Submersible Shredder Pumps. The first pump was installed in 2011, and the maintenance team immediately acknowledged how much easier it was to install the pump into the 12-foot deep wastewater

collection pit. After working reliably for a year, Anteneh decided to systematically replace the other 5 vertical column pumps in all the wastewater collection pits throughout the hotel complex.

“These are a totally different style pump than we had before, and they have solved many problems we had experienced with the old ones – clogging, constant maintenance, etc. We have less maintenance and have saved so much in preventive maintenance costs. Our down time has been drastically reduced and we know we can trust the BJM Pumps,” declares Anteneh. “We are very pleased with the BJM Pumps’ performance and the service provided by Denver Industrial Pump.”

There are many advantages of using submersible pumps over vertical column pumps:

  • Less preventive maintenance and inspection are required for submersible pumps because their bearings are permanently lubricated.
  • Submersible pumps have lower true “cost of ownership” and less mean-time-between-failure because of the submerged motor. The submerged motor allows heat generated during operation to dissipate, which lowers the running temperature. A lower running temperature increases the life span of the motor’s insulation, mechanical seals, and bearings.
  • Submersible pumps located in the liquid sump are not subjected to the temperature, elevation, or height limitations of self-primers.
  • The compact rotating element of submersible pumps make them more reliable. Long-shafted vertical pumps that utilize close clearance line shaft bushings often become worn and fail.
  • The compact and portable features of most submersible pumps makes bench-servicing easier.
  • Liquid around the submersible pump isolates noise; therefore the submerged motor/pump operates more quietly than vertical column pumps.

In today’s world, many maintenance teams face challenges when trying to upgrade their pumping equipment. So it is important to consider the cost of NOT upgrading…how much is your company really spending if maintenance is frequent and down time is excessive? Embracing the technology shift and employing modern, highly engineered submersible pumping equipment can have a big impact on both the efficiency of day-to-day operations and long-term pump life cycle costs.

This case study originally appeared in the May/June 2016 issue of Industrial Water and Wastewater Digest

Written by: Mike Bjorkman, BJM Pumps; Dawit Anteneh, Central Plant Stationary Engineers Supervisor, Sheraton Hotel; Phoenix Sullivan, Outside Sales, Denver Industrial Pump; and Ben Wells, Regional Manager, BJM Pumps

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