Sustainable Silicon Valley is grateful to have Silicon Valley Clean Water (SVCW) as a sponsor for No Drop Left Behind. SVCW is a joint powers authority agency serving the West Bay Sanitary District, and the cities of Redwood City, Belmont, and San Carlos. Their core function is wastewater treatment and reclamation for their service areas, which have a combined population of 250,000 people. SVCW reclaims an annual average of one million gallons of water a day, and three million per day during the peak flows of summer months.
SVCW works to make high quality reclaimed water accessible to local residents who wish to utilize it, and also ensures that treated water which is not reclaimed, and discharged to the San Francisco Bay, is clean and improves the quality of the Bay’s water.
I had the pleasure of speaking with Dan Child, who has served as general manager of SVCW for the past eleven years, and will also be one of No Drop Left Behind’s distinguished speakers. SVCW has and is making innovative efforts in adopting and exploring new wastewater treatment technologies, with great sustainability co-benefits. Dan Child kindly shared aspects of SVCW’s experiences and outlook in this area.
One of the major waste products rendered from wastewater treatment are biosolids. Five years ago, SVCW began working with Bioforcetech Corporation to develop the first ever biosolids to energy process, whereby biosolids are dried with very low energy consumption and then run through a pyrolysis unit, leading to the production of heat, and also power generation. Although at present, the system is only producing heat, it is still beneficial as this heat is re-circulated by SVCW into the system for the biosolid drying process: leading to greatly reduced energy consumption for a process that has historically been exceptionally energy intensive. Dan Child is optimistic that the process may start producing power within the next two years.
Along with biosolids, another product of the treatment process is methane gas. Methane is the same compound as the natural gas traditionally burned for electricity generation. SVCW is resourcefully harvesting the methane gas produced during the treatment process, and burning it in their own on-site generators, resulting in 600 kW daily power generation, which meets 60% of the treatment plant’s power demand, and results in a $700,000 per year savings in electricity bills.
SVCW has been working with Mango Materials for the past seven years, which has developed a bacteria that consumes methane and excretes a polymer that can be used to manufacture food-grade biodegradable plastic, resulting in an environmentally clean material with many applications.
SVCW has just received a $2 million grant from the California energy commission to study SAF-MBR, which is a process that uses considerably less energy to treat wastewater, by utilizing anaerobic bacteria which do not require oxygen to break down the solids, and are thus more efficient at breaking them down during the digester-phase of wastewater treatment. This process has the potential for lower energy consumption, and associated costs.
Dan Child and I discussed how SVCW’s efforts fit into the larger water management puzzle of the Bay Area, and of California. At the present time, most of SVCW produced recycled water is used for irrigation, although there are some industries such as concrete plants that are also using the water. What recycled water users have in common, is the lack of a drinking water quality-level imperative. This is a mind-set that Dan Child hopes will continue to spread in California, which as he points out, has a population that is too great to be supported by traditional sources. Along these lines, there is movement in the water industry towards using recycled water as a supplement to drinking water, and California is developing regulatory standards to make that possible. Recycled water is the least expensive, and most secure and sustainable method to meet the state’s long-term water needs. While still more expensive than Hetch Hetchy Reservoir water, it is the least expensive of the often-cited alternatives – such as desalination
The efforts of SVCW to find new, more sustainable and less wasteful water treatment methods are closer to novelty than to norm in the wastewater management sector. SVCW has been willing to be less risk averse in trying new technologies and processes in the hope of finding solutions that may lead to savings of power and natural gas, and most importantly the achievement of the best possible recycled water for human-use and a responsible treated wastewater discharge to the San Francisco Bay ecosystem. Dan Child encourages interested readers to visit www.svcw.org to learn more or contact SVCW with ideas or questions. SVCW has public tours every month, and is always available to meet with people, and explain their mission.
Quoting Dan Child: “The more people understand what we are doing, the more we can benefit the community.”