PCC Students Demonstrate Biofiltration of Household Greywater


December 20, 2005 - Local elected officials were treated to a tour of a demonstration project at Pasadena City College that could help expand local water resources and clean up the Arroyo Seco and the Los Angeles River.

Senator Jack Scott, chair of the California Senate's Education Committee, and Assemblywoman Carol Liu, chair of the Assembly's Education Committee, representatives of the Metropolitan Water District of Southern California and PCC officials toured an innovative water reclamation project located in a rooftop greenhouse on the campus.


Biology students, taught by Professor Russ Di Fiori, built the simulated wetlands which consist of six ten foot long troughs containing native plants found in local streams such as the Arroyo Seco and the Los Angeles River. The water fed into the wetlands consisted of greywater, household waste water such as that coming from a sink or wash machine. The water was tested before entering and at the end of the process to determine the ability of the wetlands to filter out potentially harmful elements such as nitrates, phosphates and bacteria. The students verified that the plants served as effective filters to reclaim the used household water.

The PCC wetlands demonstration is one of 12 Southland college and university projects to receive World Water Forum grants totaling $120,000 to research local water solutions that could result in global benefits. The World Water Forum is a program of the Metropolitan Water District in partnership with the the United States Bureau of Reclamation, the Sanitation Districts of Los Angeles County, and Friends of the United Nations.


The wetlands project was conducted by Ibrahim Haijali, Steven Cardenas, Thai Voung, Jim Liu, William Liang, Marisa Robles, Alieenthea Lam, John Krayer, Rushil Shah, and Alex Del Valle. Also shown in the picture are Assemblywoman Carol Liu, State Senator Jack Scott, Professor Russ Di Fiore, and MWD Director Tim Brick.

(Photos provided by Metropolitan Water District)

The Function of Wetlands

Wetlands are extremely rich ecosystems, and are able to support a vast number of plant and animal species. It is estimated that the wetlands of the United States support over 5,000 plant species, 270 bird species and 190 species of amphibians. Birds, mammals, amphibians, reptiles, fish, invertebrates and insects a vast number of species from each group are dependent on wetlands for their survival.

Wetlands are not only valuable in sustaining wildlife populations; they are critical to the functioning of healthy watersheds. They do so by the following functions:

* Slowing the flow of water and storing water during heavy rains or snow melts to reduce the risks of flooding

* Recharging the water table

* Purifying water and reducing pollution

* Reducing erosion

* Encouraging precipitation and air humidity

Constructed wetlands, such as those demonstrated by the PCC project, are increasingly being used to treat household and agriculture waste water as well as storm water to remove harmful contaminants.