Shaftless, Ceramic-Lined Grit Classifier New Hanover Township, PA

General Description

The New Hanover Township is located in Montgomery County, Pennsylvania. The New Hanover Township Sewer Authority maintains the sewer system within the New Hanover Township and handles the sewage of over 3,000 customers. The sewer system’s collection system includes 2 Pump Stations, New Hanover Square Road Pump Station and Samantha Way Pump Station. The treatment plant uses an activated sludge treatment process and has a plant permitted flow of 1.925 million gallons per day (MGD).

The headworks area of the plant removes inert material such as grit that is not benefitted by secondary treatment or sludge processing. Grit consists of sand, silt and other abrasive particles and is damaging to downstream equipment like pumps and centrifuges. Grit is removed from the wastewater stream in several processes. Grit is first settled in a grit chamber and pumped to a grit classifier through a cyclone on top. The cyclone captures and removes most of the grit in the stream. The balance of the stream exiting the cyclone is completely de-gritted and sent for further treatment. A small volume of the stream still contains grit and is piped to a grit classifier. As the grit settles to the bottom of the classifier tank it is slowly removed via a shaftless incline screw conveyor.

Design Parameters

1. Product Type: Grit
2. Material Density: 90 to 120 Lbs. per Cubic Foot
3. Capacity: 45 Cubic Feet per Hour
4. Duty: 7 Days a Week, 24 Hours per Day

KWS Advantages

The existing grit classifier was a constant headache for maintenance personnel. The shafted carbon steel screw with thin pipe and flights would corrode away in less than a year. The submerged tail bearing was difficult to grease and replace. KWS Environmental supplied a new grit classifier that was designed for many years of continuous operation and no down time. Every problem with the existing grit classifier was eliminated with the new KWS design. The KWS engineering team reviewed the existing unit closely to make sure that the new grit classifier would drop right in with no major modifications.

Special Features

The new KWS Environmental grit classifier was constructed from 304 stainless steel for corrosion resistance. A shaftless conveyor was chosen to eliminate the submerged tail bearing. The ¾-inch thick shaftless spiral was made from the exclusive KWS-350 micro-alloy material that is the strongest and toughest spiral on the market. The troughs were lined with ½-inch thick ceramic tiles, ensuring a tremendously long wear life while handling the abrasive grit. The classifier hopper has an adjustable weir so the rate of overflow at the top of the hopper can be varied as needed. All the existing piping matched perfectly to the new unit. The electrical components were designed to be explosion-proof, typical of headworks environment.