Catch basin inserts: Last line of defense in stormwater treatment

A catch basin insert (CBI) offers a convenient and practical method of addressing this water pollution problem. When an intercept device is placed at the catch basin grate, it directs runoff water into the CBI, where it helps remove contaminants at the drain source. The CBI device is placed under the grate to intercept and treat the early low flow runoff or first flush event.

The basic sequence of operation of a catch basin insert begins when first flush event water is directed into a housing assembly by a deflector. Sediment and heavy solids tend to settle to the bottom of the housing. As the water level starts to rise, it drains through a vertical filter cartridge with layers of media. Dirty water first passes through a strainer and filter that blocks the larger...

Catch basins are typically approx-imately 45 to 60 centimeters (cm) in diameter or rectangular with 40-cm x 60-cm or larger grates. They may be 1.2 meters (m) to 1.8 m deep or more. The catch basin acts as an interceptor and becomes a practical location to treat the first flush runoff.

Periodic maintenance of CBIs includes inspection and sediment and debris removal from the unit housing during dry summer periods. Several inspections should be carried out throughout the year, including cleaning leaves and trash debris near the grate entry.

CBIs have been installed in industrial, residential, and commercial areas, requiring minimal maintenance, in stormwater systems across the United States (US) for many years. In a residential development in the US state of California’s San Joaquin Valley, more than 1,300 catch basin filters are installed. During routine storm system inspections maintenance staff report that pipelines are...

John J. Paoluccio, an engineer and inventor of patented catch basin inserts and other environmental products, is the president of IRI Products, based in Salida, California, US.