Wastewater good for aquaculture

Wastewater from kitchen sink and washing machine, known as "gray water," can be used for growing aquatic plants and fish.

Attesting to this are studies done by Aquatic Biosystems, a private R&D group based in Laguna Bay, monitored by the Los Baños-based Philippine Council for Aquatic and Marine Research and Development (PCAMRD).

In tests, it was found that with the use of kitchen wastewater, kangkong (Ipomea aquatica) had a growth that was favored with up to 20 percent concentration for the wastewater in the culture medium.

"Using laundry wastewater, a concentration of only 10 percent was found to be favorable for the plants," PCAMRD noted.

In a paper presented recently in China by PCAMRD executive director Dr. Rafael D. Guerrero III, he reported that an annual tilapia production of 8.7 tons per hectare is possible with fertilization provided only by laundry wastewater at 1.28 liters per cubic meter per day. – Rudy A. Fernandez