Reducing Emergency Sewer Repairs

Wastewater treatment plant operators have dealt with clogging problems at their plants and pump stations for decades, but the meteoric rise in the use of so-called flushable wipes and other non-dispersible products has accelerated the problem to epidemic proportions. Wet wipe consumption alone has nearly tripled in the past decade and continues to grow.

When paper towels, cleaning cloths, baby wipes, feminine hygiene products and cosmetic wipes are flushed down the toilet, they ultimately reach influent pump stations at wastewater treatment plants relatively intact — clogging and jamming pumps, check valves and screens and significantly increasing maintenance, repair and operational costs.

This problem is in no way limited to municipal wastewater treatment facilities. The growing volume of non-dispersible solids is just as much a serious and growing issue for commercial operations such as healthcare facilities, multi-family developments, high-traffic convenience stores and big box retailers. Many of these facilities maintain on-site pump lift stations, which are the first to be impacted by this non-dispersible debris.

Big Box Dilemma

The on-site pump stations that handle wastewater effluent from big box stores, and particularly those selling apparel, must also deal with a significant volume of product packaging, security tags and clothing that is flushed down restroom toilets as a result of theft. Consequently, these pump stations more frequently become severely impacted, necessitating a high volume of costly emergency repairs and increased municipality fees for discharging debris into sewage lines.

“Just about any company that has a lift station runs into non-dispersible debris as a problem,” said Wade Stafford, vice president of wastewater services at AQUALIS, a national, full-service maintenance and construction company. “We have found that these retail sites, however, experience a higher level of damage to pumps, compared to other industries, simply because of the amount of harder solids or elastic-based clothing that gets flushed down the toilet.”

“A correctly-maintained maintenance program can curb the problem, which helps to keep the pumps functioning and forecast damage,” added Stafford. “But emergency response for repairs to these pump stations caused by the impact of non-dispersibles is inevitable, and can approximate $30,000 annually.”

Assessing Alternative Solutions

Designed to fit almost anywhere, the four-foot diameter prefabricated, fiberglass-reinforced polyester manhole sewage grinder system is customizable to fit exact site requirements such as depth, and inlet and outlet pipe diameters. It also includes the option of a hatch or flat cover. A factory-installed guide frame and ladder make access the grinder easy.

“The manhole is simple to install, by digging down to the sewer line, creating a concrete pad for the fiberglass manhole unit to rest on, then tying it in the sewer lines,” added Smith. “The pre-packaged system avoids costly civil construction work and is easy to maintain, requiring only semi-annual inspections.”

At the heart of the Monster Industrial Manhole is a JWCE 3-HYDRO, dual-shafted, open-channel, immersible-motor grinder that can handle much larger debris than the lift pumps. Two stacks of sharp, hardened-steel cutters rotate slowly with high torque, easily grinding large solids into small particles. Side rails within the grinder are designed to effectively drive debris into the cutters. Integrated steel scrapers help the cutters clean out quickly to maintain throughput. The grinder can handle flows from 370 to 5,620 gallons per minute.

The Monster Industrial Manhole grinder utilizes JWCE’s patent-pending Wipes Ready technology, which is designed to shred any disposable, non-dispersible items that commonly clog sewage pumps into small enough pieces that they will not reweave into ragballs in sewage systems.

“While conventional grinders make long strips out of wipes that reweave into ropes, the Wipes Ready technology uses serrated tips that puncture and tear at the fibers, leaving small pieces that stay in suspension, and are easier to handle by traditional sewage pumps,” continued Smith. “This optimized cut control prevents build-up, keeps the cutters clean, and maintains high flow. The smaller pieces are then removed at the headworks of wastewater treatment facilities.”

The components of the Monster Industrial Manhole are controlled with a programmable logic controller (PLC), with sensor monitoring through remote telemetry via the cloud. Faults in the pump such as vibration, high amperage overload or high water levels in the manhole can be displayed on human machine interface (HMI) at a remote location.

“Remote telemetry permits us to dial into exactly what is going on with the pump station in real time,” explained Stafford. “We can see what is happening many times before the fault turns into a major situation, and take steps to resolve it, such as before there is an overflow into the parking lot or a backup of sewage into the facility.”

AQUALIS records these metrics and maintains a historical database for each manhole, encompassing any type of damages, manhole condition, pump condition and component condition, and factors this data with its preventative maintenance programs.

This comprehensive approach saves on costly emergency service calls and mitigates equipment damage.

Reducing Emergency Repair Costs

AQUALIS’ installation of the first two Monster Industrial Manholes with one of its big box customers has produced significant return on investment. The two, separate installations were both competed in mid-2017.

One facility in Madison, Ind., with a three-year average annual repair cost of $30,600 per year prior to installation of the Monster Industrial Manhole, has now accrued $0 annually in repairs after more than 18 months in operation.