Partnering with States and Local Communities on Water Reuse
Published January 26, 2018
Safe and reliable water supplies are important to life, healthy communities, and booming economies. Knowing this, the San Francisco Public Utility Commission adopted the Onsite Water Reuse for Commercial, Multi-family, and Mixed Use Development Ordinance, commonly known as the Non-potable Water Ordinance, in September, 2012. This ordinance added Article 12C to the San Francisco Health Code, allowing for the collection, treatment, and use of alternate water sources for non-potable applications in both individual buildings and at the district-scale (i.e., projects that include two or more buildings). Alternate water sources include those such as rainwater, stormwater, and foundation drainage.
Working with EPA researchers, San Francisco and other state and local governments around the country concerned with water quality and quantity have been modeling exposure risks to create a regulatory risk-based framework so that water can be recycled and reused safely. According to EPA researcher Jay Garland, PhD, this framework is important to define treatment options and to monitor treatment to reduce the risk of acute microbial infections from the use of these alternate water sources.
To help develop the framework, EPA modeled the risks involved in using various types of site-collected waste water for non-potable uses, such as flushing toilets or doing laundry. Garland said, “We are modelling exposure risks so that communities adopting water reuse options would know what level of treatment they would need to make sure their water is safe to use.”
EPA does not currently regulate water reuse, but this framework provides information that utilities and state and local health departments can use to regulate it. For example, in San Francisco, any new commercial, multi-family, or mixed use buildings need to be able to use alternate water sources for water reuse.
The researchers are looking at different technologies such as aerobic and anaerobic bioreactors (i.e., systems that use microorganisms to treat waste water) for water reuse when determining the risk-based framework. Anaerobic bioreactors are also able to capture methane for energy use. They were able to draw from ongoing research with the Department of Defense (DoD). Together EPA and DoD are piloting the largest scale experiment using anaerobic bioreactors at Fort Riley, Kansas, as part of a NetZero project. NetZero is a set of strategies, approaches, and technologies that help communities achieve the goals of consuming only as much energy as they produce, achieving a sustainable balance between water availability and demand, and eliminating solid waste sent to landfills.
State and local governments have to decide whether their future involves a centralized system of water reuse where they maintain more control, but will still have costs of pumping waste through their long distribution network. San Francisco is exploring another option which decentralizes part of the system by making individual building owners responsible for their water reuse.
Overall, water reuse is important because, as Garland says, “Some areas are driven by water restrictions, such as California, but in New York City, for example, wastewater is taxed, so building owners are able to reduce their taxes by reducing their water bills, their sewer capacity, and the city’s potential for combined sewer overflows.”
This research is ongoing and Garland, as part of the U.S. Water Alliance National Blue Ribbon Commission for On-site Non-Potable Water Systems, will continue to share findings to inform guidance for the regulatory frameworks and business models that utilities can employ in a world of less water use. The Commission is also identifying research gaps going forward.