(156f) Performance Evaluation of a Low Cost and High Rate Vertical Flow Wetland for Residential Graywater Treatment and Reuse

Authors: 
Rahardianto, A., University of California, Los Angeles
Stenstrom, M. K., University of California, Los Angeles
Cohen, Y., University of California, Los Angeles



Water shortages in urban environments across the US and around the world have sparked increased interests in the development of sustainable water practices and technologies. Despite increased sustainability efforts, water reuse in the United States accounts for only ~1% of the nation’s total water supplies. Water reclamation and reuse through centralized suppliers (i.e. municipalities or water agencies) represent a major challenge given the lack of infrastructure and operational costs for treatment and distribution system for reclaimed wastewater and its reuse. One possible approach that addresses, in part, the above challenges is to utilize point-of-use (i.e. onsite) treatment to generate non-potable water source for onsite reuse. Such onsite reuse activity will expand the nation’s water recycling efforts driven by end-users or small communities (e.g. multifamily homes) and augment the existing water resources portfolio. Accordingly, it is argued that on-site treatment and reuse of graywater is a viable option in residential and non-residential premises. The key challenge of encouraging such a practice is the lack of affordable and simple treatment technology suitable for residential users. In order to meet the above challenge, the present study presents a low cost, high rate, compact vertical flow wetland (CVFW) system for graywater treatment. The developed small footprint graywater treatment (~1m2) was field tested in a single family home in Los Angeles with the treated water being used for irrigation. The kinetics of the graywater treatment system was characterized using a composite model for the vertical wetland configuration and system operation was accordingly optimized. Results from the field study demonstrated that the CFVW system is capable of removing up to 90% of total organic carbon and up to 99% of turbidity. The present approach has a potential for deployment in multifamily homes for onsite treatment and reuse of graywater with an estimated return on investment within 2 years.