Grinders Protect Wastewater Treatment System




The wastewater treatment system at Bayer Corp.'s chemical intermediates plant in New Martinsville, W. Va., processes 4 million gallons per day (gpd). The plant's environmental management team employs custom-engineered Muffin Monster grinder units from JWC Environmental of Costa Mesa, Calif., to prevent plugging and premature wearing of pumps, lines and other equipment in its wastewater treatment and waste incineration systems.

"One [Muffin Monster] unit has been in-line for over 11 years, a second for more than nine, and a third was retired after eight years only because we modified the waste stream," says Kirsten Lawson, operations engineer in the plant's environmental control department. "They do exactly what they are supposed to do, without breakdowns, needing only biannual blade replacement as preventive maintenance. It's a very durable piece of equipment, and blade replacement can be performed within a single shift."

The grinder's cutter elements are provided in a variety of sizes for both in-line and channel configurations.

Lawson says one custom grinder is located just before the entrance to a 24,000-gallon (gal.) Resource Conservation and Recovery Act (RCRA)-permitted batch load wastewater storage tank, which is part of the plant's hazardous waste incineration system.

"For the last seven years, we've had a grinder there processing material generated primarily from cleaning operations," Lawson reports. "The tank is designed to handle aqueous wastewater. It has a -inch carbon steel pipeline leading to the incinerator, so we need to prevent large pieces of byproducts, which can be up to 2 inches in diameter, from entering the tank. The grinder [processes] 150 gallons per minute via [a] centrifugal pump during loading operations."

In a similar application, Lawson says a Muffin Monster grinder was installed between a tank that holds sludge from the primary clarifier and the incinerator feed pumps that follow.

"We run the sludge through it there in order to protect a progressive-cavity, 5- to 7-gallon-per-minute pump from plugging," she explains, "as well as [to protect] the 1-1/2-in. piping coming out of the pump. The sludge is 90 to 95 percent water, plus organic solids, plus plastics and foam materials that are less than 2 inches in diameter. The grinder [processes] 5 gallons per minute, and has been on-line successfully for more than nine years."

Elsewhere, one of the wastewater system's feed streams originates from a sump that services a RCRA-permitted material handling pad. The 5,000-gal. sump collects drainage, including solids, from the pad via gravity drain.

"For eight years, we had the submersible sump pump direct the discharge via a 4-inch line into one of the grinders," Lawson says. "This was to prevent plugging of centrifugal and progressive-cavity pumps downstream, which in turn are discharging sludge for further treatment.

"The grinder [processed] 1-inch to 2-inch diameter particles of plastic, foam, wood and other debris generated by housekeeping, process reactor cleaning operations, and maintenance preparations for pumps and process lines," she adds. "It protected the pumps by sizing particles down further."

According to Rob Sabol, research & development engineeering manager for JWC Environmental, various cutter combinations allow Muffin Monster grinders to provide particle sizes as fine as 1/4 in. for 95 percent of the ground material. He added that cutter elements are engineered in many variations to accommodate specific needs, and are provided in a variety of sizes for both in-line and channel configurations.

The units adapt to most applications with little or no modification to piping or power, and offer high-pressure capabilities, with no seal flush required and no packing gland to adjust.

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