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Onsite Non-Potable Water Reuse Research

Produced water from buildings-Water ReuseWithin a building, several water sources are generated that can be treated and used onsite or in a local area for non-drinking water purposes, such as toilet flushing, clothes washing, and ornamental plant irrigation. Original photo credit: San Francisco Public Utilities CommissionIncreasing pressures on water resources have led to greater water scarcity and a growing demand for alternative water sources. Onsite non-potable water reuse is one solution that can help communities reclaim, recycle, and then reuse water for non-drinking water purposes. Onsite non-potable water reuse systems (ONWS) capture and treat water sources generated from within or surrounding a building, such as wastewater, greywater, stormwater, or roof collected rainwater. The treated water is then reused onsite or locally for non-drinking purposes, such as toilet flushing, clothes washing, and ornamental plant irrigation.

EPA is collaborating with states and utilities who are facilitating the development of ONWS to define treatment and monitoring approaches that will ensure safe adoption and to build the utility business case for implementing such systems.

Technical Brief: Onsite Non-Potable Water Reuse Research
Webinar Recording: Onsite Non-Potable Water Reuse with Expert Panel Discussion (October 31, 2018)Exit

Recycling of waterRisk-Based Modeling

EPA researchers are conducting risk-based modeling to understand the human health risks associated with onsite reuse of locally-collected waters, such as wastewater, greywater, stormwater, and roof-collected rainwater, for non-potable applications in and around buildings. Quantitative Microbial Risks Assessment (QMRA) models were developed to characterize potential risks associated with these systems and to define the levels of pathogen removal needed to perform reuse safely. These reduction targets, reported for each of the three major groups of waterborne pathogens (viruses, bacteria, and protozoans) across various combinations of water sources and end uses, provide specific performance metrics for treatment systems.

This research also includes the evaluation of initial pathogens concentrations in different onsite water sources as well as modeling the risks associated with proposed treatment options and ONWS cross-connections.

Recent Research Publications:

Recycling of waterMonitoring of Treatment Performance

Monitoring the treatment processes in ONWS is necessary to ensure that recycled water is treated appropriately to reduce pathogens for safe application. Since pathogen monitoring is inefficient, other non-pathogenic microorganisms are being investigated to stand in for pathogens. This research involves describing and quantifying the microorganisms, both bacterial and viral, found in these locally-collected wastewaters. In addition, the alternative microorganisms are evaluated to ensure they are removed in a similar way as pathogens are during ONWS treatment. The use of alternative microorganisms will facilitate monitoring of ONWS to verify that treatment systems are performing as intended.

Recent Research Publications:

Recycling of waterLife Cycle Assessment

While local entities have identified a number of drivers for implementing ONWS, ranging from addressing water scarcity to the development of green space within urban areas, quantifiable data is needed on the life cycle impacts and costs to build the business case for implementation. From the perspective of the local utility or government, the implementation of ONWS must account for the costs of installing and operating the ONWS to the benefits derived (e.g., avoided drinking water costs). To provide insight into this system level perspectives, life cycle costs and impacts were assessed for ONWS of various scales and types.

Recent Research Publications:

Recycling of waterCollaboration

Hassalo on 8th Wastewater Treatment & Reuse System in Portland, OregonHassalo on 8th Wastewater Treatment & Reuse System in Portland, Oregon—an example of an onsite non-potable water resue system.EPA researchers are committed to active engagement with various partners and stakeholders to ensure that implemented water reuse protect public health. One of these partners, the National Blue Ribbon Commission for Onsite Non-Potable Water Systems (NBRC)Exit, is an nationwide group of utilities and state/local public health agencies that are interested in advancing the safe adoption of ONWS. To that end, NBRC has produced several industry guidance documents that incorporate the results of EPA research in this area.

Recent Research Publications: 

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