Advancing Water Conservation through Decentralized Renewable Off-Grid Water Treatment

Water Management



​The Decentralized Renewable Off-Grid Wastewater Treatment (DROWT) team—led by Dr. Reza Baghaei Lakeh, mechanical engineering professor, and Dr. Ali Sharbat, associate professor of civil engineering—developed an off-grid solar-powered graywater treatment system for nonpotable use, such as for washing dishes and clothes, in single households. Water drained from bathroom sinks, laundry machines, dishwashers and showers are captured for treatment. 

A three-stage process treats the water through microfiltration, solar-driven reverse osmosis and ultraviolet disinfection. The developed system is capable of reclaiming 90 to 100 gallons of water per day, equating to 60 percent of residential graywater waste, with a recovery rate of 62 percent. 

Sponsors are Craig Netwig (’71, chemical engineering), the grandfather of the reverse osmosis water filtration process, and Metropolitan Water District of Southern California. In 2018, Netwig donated $145,000 to the College of Engineering at Cal Poly Pomona (CPP) for research into water reuse systems. 


Engineering students won second place at the Metropolitan Water District’s 10th annual Spring Green Expo for DROWT. 

DROWT placed second at the 2018 Bronco Startup Challenge at Cal Poly Pomona. Many of the judges, innovators and entrepreneurs present expressed interest and admiration of the DROWT concept and functional prototype showcased. 

In addition, DROWT won first place at the College of Engineering’s 2019 Project Showcase, where each CPP engineering department presented their best projects to alumni, industry, faculty, staff and students