Shredder solution helps sewage flow

Access to the pumps for maintenance required an entire day to service a clog. Help arrived in the form of 15hp BJM shredders.


The SK Series pumps are designed to shred solids before passing the liquid.

 

On October 28, 2012, Hurricane Sandy swept over Ellis Island, Liberty Island, and much of the East Coast. The Ellis Island Immigration Museum reopened on a limited basis one year later, but repairs to the buildings and infrastructure would continue for many months.

Although the damage to Ellis Island was extensive, the island's antiquated sewage system was fraught with problems long before Hurricane Sandy came ashore. At that time, New Jersey-based Pump Express Services had been providing maintenance to the island's sewage ejector system for a couple of years.

Two-pump system

According to Pump Express sales manager Fred Hettinger, in the two years before Sandy they were called to the island numerous times in response to high water alarms, clogging and ultimately a failed pump. "They had a two-pump system and when one pump failed they let the system run on the other," he said. Then, the second pump failed and they had nothing."

Hettinger explained that a significant problem was that the old pumps were a simple ejector type and didn't break down solids. Along with the sewage flow on the island there was also a significant amount of debris, with synthetic fibers being particularly problematic, that routinely clogged the system.

In addition to the clogging problem, physically getting to the pumps in order to service them was a lengthy and labor-intensive ordeal. "The old system required four techs and an entire day to service a clog. A man had to physically descend into the 30-ft pit to detach and later reattach the pump," Hettinger said.

Left with only minimal sewage disposal, and faced with a grand reopening to the public targeted for July 4th, 2013, the island's maintenance engineers reached out again to Pump Express Services, this time for a more permanent solution. "We submitted a proposal to replace the old pump system with a pair of 15 hp BJM shredders," Hettinger said. "We've been using BJM shredders for four or five years now and everything we've been able to throw at them they've been able to handle."

In recent years, Ellis Island has become one of the most popular tourist destinations in the National Park Service.

 

Improved servicing

In addition, Pump Express proposed replacing two 20-ft sections of steel pipe, along with discharge and base elbows, installing a more efficient rail system and resurfacing the base of the sewage pit. Instead of four techs and an entire day, the new system can be serviced by two techs in four hours. The two new BJM shredders lent themselves well to this new configuration. If a customer is ordering a new pump it's likely because the one they have has failed or is about to.

Hettinger said that an important additional benefit of ordering the BJM Pumps was that the lead time for their delivery was about half of what it would have been for new ejector pumps equivalent to the ones that had failed. He said that was impressive considering "all this stuff has to be built. A lot of times the parts still have to be manufactured."

The BJM pumps were delivered in about four weeks. The estimated delivery time for the ejector pumps had been 10 weeks. In April 2013 Pump Express installed a pair of 900-pound BJM SK Series shredder pumps into the revamped Ellis Island system. The pumps can handle 845 gpm of wastewater at heads of up to 94 ft.

Designed to shred solids

The SK Series pumps were chosen specifically because they are designed to shred solids before passing the liquid. The shredder pumps leave solids slightly larger than if they were passed through a grinder pump. The shredding action is produced through use of a unique FangTM non-clog cutting impeller with tungsten carbide vane tips against a high-chrome ‘tooth shaped’ diffuser plate. The cutting tips shred solids against the pump suction plate, continuously ripping the solids apart with 360° shredding action.

The SK Series shredder pump works on many objects that would clog an ordinary pump. Other quality features built into the SK Series pumps that supported their recommendation for the Ellis Island installation include the following:

  •  The 304 stainless steel motor housing helps protect the pumps from abrasion and premature wear caused by the harsh saltwater environment.
  •  The motor is protected by double mechanical seals. The lower seal is made of silicon carbide/silicon carbide and the upper seal is made of carbon/ceramic. In addition, a lip seal has been installed above the impeller that helps prevent abrasives, such as sand, from entering the seal chamber.
  •  Winding protection and NEMA Class F motor insulation allow the motor temperature to rise to 180° Fahrenheit.
  •  An automatic switch turns the pump motor off if the temperature and/or amp draw gets too high. When the motor cools the switch will automatically reset and the pump will restart.
  •  A hardened cast iron exterior stands up to rough handling and pumping of sandy water unlike pumps with soft resin impellers or plastic exterior components.

About six months after installation a team from Pump Express went back to Ellis Island to make sure the new pumps were performing as anticipated.

"We're now going on a year and a half and haven't had any issues," Hettinger said. “That's a vast improvement over the previous average of a visit every six months. I bet in the last 18 months if we had had to go out there three more times it would have cost them half of what the upgrade cost them," he added.