Cortech Engineering, which provides engineering and pump support services to many industries throughout California and Nevada, was contacted by a municipal water district that has a water reclamation facility which recycles water to meet Title 22 tertiary standards. Title 22 recycled water, or tertiary water, is used for a wide variety of irrigation and industrial uses. Local refineries rely on this California-based municipal water district to send up to 5 million gallons of Title 22 recycled water per day to be further treated and used for boiler feed and cooling tower applications. The municipal water district had previously worked with Cortech Engineering and decided to contact them in 2013 to discuss a solution that would help their water reclamation facility save $23,000 a year in replacement pumps.
The water reclamation facility had been experiencing frequent pump failures of their submersible sump pumps, which operated in their microfiltration backwash waste pits. Their microfiltration backwash waste pits contain the spent waste that is the result of processing water to Title 22 standards. The liquid in these MF backwash waste pits contains chemicals and solids, such as oxidized ferric and non-ferric particulate. These solids had been causing clogging problems for the submersible sump pumps operating in the pits, which range in depth from 7 to 20 feet. The liquid in the MF backwash waste pits also reaches extremely hot temperatures. These high temperatures had been causing a series of installed submersible pumps to overheat and fail.
The maintenance team at the municipal water district was tired of replacing the submersible pumps every 6 months, so they contacted John Forgette, Outside Sales Engineer at Cortech Engineering. Forgette was asked to recommend submersible pumping equipment which would be better suited for their specific application. Forgette considered the maintenance teams’ major concerns:
- High Temperatures – most submersible pumps cannot withstand pumping liquids at temperatures higher than 104 degrees Fahrenheit. Because the liquid in the MF backwash waste pits were consistently around 200 degrees Fahrenheit, it was critical to select a submersible pump that could pump extremely hot liquids.
- Pumping of Solids – the particulate in the MF backwash waste pits had been clogging the submersible pumps. The frequent clogging issues caused consistent pump failure and resulted in costly down-time.
- Pump Reliability – each MF backwash waste pit utilizes a single submersible pump operating in 24/7 continuous duty. The water reclamation facility needed a durable submersible pump that could withstand the liquid’s high temperatures, pump the solids, and operate reliably in 24/7 continuous duty.
Forgette worked with an applications engineer at BJM Pumps to find the perfect pump for the water reclamation facility’s MF backwash waste pits. The applications engineer at BJM Pumps helped Forgette to select a BJM Fahrenheit Series Submersible Pump. The KZN 110F Heavy Duty Submersible Slurry Pump was deemed the best solution for the following reasons:
- The KZN 110F is specifically designed to handle high temperatures. BJM’s Fahrenheit series pumps are engineered to pump liquids which are too hot for conventionally built submersible pumps. The pump, which utilizes fluoroelastomer rubber for high temperature service and wide chemical resistance, can handle temperatures up to 200 degrees Fahrenheit.
- The KZN 110F uses an abrasive resistant 28% chrome iron agitator. The high-chrome agitator keeps solids suspended in the liquid to prevent the pump from clogging. No clogging means no pump failure, which translates to reduced maintenance costs.
- The KZN 110F is engineered with 28% chrome iron components. These components include a semi-open impeller, which handles abrasive solids with concentrations as high as 70% by weight; and a replaceable wear plate on the suction side which minimizes loss of pump performance as a result of erosion.
- Durable construction to ensure 100% uptime and pump reliability. The KZN 110F has a stainless steel shaft and shaft sleeve which reduces shaft wear from abrasive materials and corrosive liquids. The pump volutes are cast from hardened ductile iron (300 Brinnell hardness) and are twice as abrasive resistant as standard ductile iron. This slurry pump model is protected by double silicon carbide mechanical seals, which are housed in a separate oil-filled seal chamber. The heavy duty lip seal offers additional protection for the mechanical seals. The motor is protected with Class R motor insulation, built in amperage (FLA) and temperature overload protection.
Forgette reviewed the features of the KZN 110 F submersible slurry pump with the maintenance team at the water reclamation facility. They agreed with the recommendation and opted to include the Seal Minder ® seal oil leak detector, which is used in conjunction with an alarm circuit in the pump control panel. The water reclamation facility purchased one top discharge KZN 110F to see how it would perform in one of their MF backwash waste pits. “The KZN was installed in September of 2013 and has been running great ever since. Having that agitator has really helped because it pulls those solids up in the pit instead of letting the solids settle around the pump,” states Forgette. “The KZN is doing what it is supposed to do and this means reduced downtime and labor expenditures,” he continues. “The water reclamation facility is currently looking to install a second KZN 110F in another Title 22 waste pit which is located in a different section of the plant. They are planning to replace many of their existing submersible pumps with the BJM Pumps because the improved pump reliability is having a significant impact on their maintenance budget.”