Environmental management for Bayer Corporation's chemical intermediates plant has taken advantage of custom-engineered grinder units to prevent plugging and premature wearing of pumps, lines, and other equipment in its wastewater treatment and waste incineration systems. The Muffin Monster® grinders are manufactured by JWC Environmental® of Costa Mesa, CA.
"We had plenty of problems with large-sized debris plugging piping, pumps, and other equipment prior to the installation of the Muffin Monsters," said Kirsten Lawson, operations engineer in the plant's environmental control department.
"One 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. 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 plant, which makes chemical intermediates for the automotive and appliance industries, as well as for a variety of coatings applications, has a wastewater treatment system that routinely processes 4 mgd. In a four-step process that includes neutralization, clarification, biotreatment, and carbon treatment, the system is operated to meet permit levels for the plant's National Pollution Discharge Elimination System (NPDES) permit.
Lawson said one application for the custom grinders is before the entrance to a 24,000 gallon, RCRA-permitted, batchload 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," she said. "The tank is designed to handle aqueous wastewater. It has a 1 inch carbon steel pipeline leading to the incinerator, so we need to prevent large pieces of by-products, which can be up to 2 inches in diameter, from entering the tank. The grinder sees 150 gallons per minute via centrifugal pump during loading operations."
In a similar application, Lawson said she deployed a Muffin Monster grinder between a tank holding 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, 5-7 gallon per minute pump from plugging," she said, "as well as protecting the 1 1/2 inch piping coming out of the pump. The sludge is 90-95 percent water, plus organic solids, plus plastics and foam materials that are less than 2 inches in diameter. The grinder sees 5 gallons per minute, and has been on line successfully for over nine years."
Elsewhere, one of the wastewater system's feed streams is from a sump that services a RCRA-permitted material handling pad. The 5000 gallon sump collects drainage, including solids, from the pad via gravity drain.
A vacuum truck might dump a load onto the pad, or gravity fill may occur via rain or process loading. When the sump fills, a 350 gallon per minute submersible sump pump starts. Pad drainage is sometimes dewatered and/or pre-screened before being directed into the sump, which is agitated and maintained at a controlled level.
"For eight years, we had the submersible sump pump direct the discharge, via a 4 inch line, into one of the grinders," Lawson said. "This was to prevent plugging of centrifugal and progressive-cavity pumps downstream, which in turn are discharging sludge for further treatment."
"The grinder saw 1-2 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. It protected the pumps by sizing particles down further.
"The objective was to prevent pumps from wearing out prematurely, and also to minimize particle size entering the primary clarifier, which also protects equipment further downstream from abnormal wear and plugging. We retired the grinder after successful long-term service when we removed the contaminants it was handling from the waste stream."
According to Rob Sabol, research and development engineering manager for JWC Environmental, various cutter combinations allow Muffin Monster grinders to provide particle size as fine as 1/4 inch 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 are commonly deployed in wastewater, chemical, petrochemical, pulp & paper, food processing, and other industrial applications, as well as for a wide variety of recycling and remediation uses. They effectively reduce particle sizes for wood, plastics, rocks, nuts, bolts, wire, sludge, and virtually any other foreign material that could otherwise damage waste stream and process equipment, while reducing handling costs associated with solids removal.
They adapt to most applications with little or no modification to piping or power, and offer high-pressure capability, with no seal flush required and no packing gland to adjust.