Graywater Treatment Technology Alternatives Analysis
San Francisco Public Utilities Commission, California
Project
Highlights
- Graywater treatment and water quality analysis.
- Research of microorganism and pathogen concentration.
PROJECT GOALS, ACHIEVEMENTS, AND BENEFITS
The SFPUC is investigated the possibility of reusing graywater in institutional settings, including for toilet flushing. McGovern McDonald Engineers provided a literature review to examine the occurrence and reduction of microorganisms in graywater. This information helped the SFPUC focus the subsequent graywater sampling and testing study, and to plan treatment technologies to meet State requirements and protect public health. Research included the concentrations of indicator organisms in various graywater sources, the link between indicator organisms and waterborne pathogens, and the reduction of indicator organisms by different graywater treatment technologies with the consideration of disinfection by-products.
Development of a Low Impact Development (LID) Life Cycle Cost Benefit model that determines the costs and benefits of stormwater measures to both the customer and for the SFPUC.
Assessed the methylation potential and bioavailability of mercury discharged from point sources for the Water Environment Research Federation (WERF).
Identified stormwater and recycled water cost and benefits to the customer and SFPUC with implementation of LID techniques.
Development of stormwater best management practice O&M life cycle costs for street installation as part of the San Francisco Better Streets Plan.
Provided NPDES regulatory and permitting support for treated wastewater and stormwater discharges and Combined Sewer Overflows (CSOs) to the Bay and Pacific Ocean.
Development of a modeling tool for States and NPDES permit holders to assist nutrient management strategies for the Water Environment Research Federation.
Reviewed NPDES stormwater documents for transfer from private to SFPUC authority and recommended future monitoring program improvements for the SFPUC’s Mission Bay Development.