Stainless Steel Shafted Grit Classifier Inland Empire Utilities Agency in Chino, CA

General Description

The Inland Empire Utilities Agency (IEUA) is a regional wastewater treatment agency and responsible for serving approximately 830,000 people over 242 square miles in western San Bernardino County in California. For this project, the IEUA required a new KWS Environmental Grit Classifier to separate grit from wastewater and convey the grit to a waste bin. Untreated wastewater grit consists of inorganic solids such as sand, ash and gravel. The amount of grit in wastewater depends on if the source is from sanitary, industrial, stormwater or other sources. Grit is extremely abrasive, forms plugs and damages pumps and sedimentation tanks if not removed.

Design Parameters

KWS Advantages

An engineer from KWS Environmental was visiting the site for another project and noticed the existing grit classifier was old, rusted, and leaking liquids. KWS Environmental is a full-service conveying and processing equipment manufacturer and has the capabilities to design and manufacture grit classifiers to meet the demands of specific applications. An engineer from IEUA provided basic information from the old, existing grit classifier to KWS Environmental for our engineering team to create a new solution. The KWS Environmental design incorporated many improvements based on the input from IEUA. KWS kept the same footprint as the old solution, making the new unit a direct drop-in replacement. The new design was quickly approved due to the diligence of both the IEUA and KWS. KWS Environmental provided a new grit classifier including flow valves, spray nozzles and structural supports. The grit classifier was fully assembled and water-tested at KWS to ensure there were no leaks in tank and that the unit would meet the design specifications.

Special Features

A KWS Environmental Grit Classifier consists of a large reservoir tank with an inclined shafted screw feeder in the bottom to remove grit from the wastewater stream. Wastewater enters the reservoir tank through an 8-inch pipe connection. Grit falls out of suspension by gravity and settles to the bottom of the reservoir tank and into the inclined screw feeder. The inclined screw feeder rotates very slowly (less than 20 rpm) so the grit is not agitated and put back into solution. The grit travels up the inclined screw feeder and is delivered to a container for disposal. The return water discharges over an adjustable weir and reenters the wastewater treatment process. The KWS engineering design team created a new solution for IEUA that would last for many years. The KWS Environmental Grit Classifiers was manufactured from 304 stainless steel instead of carbon steel for much better corrosion resistance. Internal baffles were added to reduce water turbulence and promote better grit settling. The KWS Environmental design also included bolt-on covers for water-tight construction, pipe nozzles for cleaning and drainage, and abrasion resistance AR400 steel screw flights.