San Francisco has been at the forefront of water conservation. A 2012 ordinance established standards for reuse, and it was updated in 2015 to require new buildings larger than 250,000 square feet to collect, treat and use gray water, a term for wastewater minus toilet waste.
Rafael Mandelman, a member of the city’s Board of Supervisors, has proposed doubling the amount of water that new buildings need to collect and reuse, and including buildings of 100,000 square feet or more.
An analysis in Austin, Texas, predicted that the number of water customers in the fast-growing state capital would quadruple in 100 years. To meet some of that demand, the city offers incentives for developers to install reuse systems, and it plans to eventually make them mandatory.
“It’s a paradigm shift, seeing building owners bring their own water to the table, so to speak,” said Katherine Jashinski, a supervising engineer for Austin focused on on-site water reuse programs. “Companies moving here from California are interested in sustainability and want to make sure there will be a secure water supply.”
Cutting-edge examples will include even more resource and energy savings. In San Francisco, a system that Epic Cleantec will install in a proposed 55-story mixed-use development called 10SVN will recycle not just black water, saving an estimated $12 million over the first decade, but also solids in the waste stream into organic soil. It will even recover and reuse the heat energy from wastewater.
“Wastewater isn’t really waste at all,” Mr. Tartakovsky of Epic Cleantec said. “It’s clean water, it’s organics, it’s nutrients, it’s energy we can redistribute, ultimately resulting in no waste at all.”
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