On-Site Direct Potable Reuse: A New Approach to Improving Groundwater Sustainability

Tuesday, December 5, 2017: 1:20 p.m.
Adam Arnold, MASc , Tangent Company, Chagrin Falls, OH
Philip Schmidt, PhD, AStat , Philip J. Schmidt Technical Consulting Inc., Guelph, ON, Canada

In many regions of the United States, and elsewhere, groundwater supplies are rapidly diminishing due to overuse or becoming increasingly contaminated. Groundwater is the conventional source for potable water in millions of houses and businesses without connections to centralized water systems. On-site direct potable reuse (DPR) is a new approach to reduce withdrawal of groundwater from aquifers via private wells and release of partially treated wastewater into the subsurface via septic systems. Specifically, the water that has been used by a home or small business is recycled to yield purified water that is safe for all indoor uses rather than being discharged to the septic system as a waste product. In addition to maintaining a potable water supply, on-site DPR could preserve and protect aquifers by reducing groundwater withdrawals that are not necessarily replenished by infiltration of septic system effluent, and by reducing subsurface release of pathogens, nutrients, and other contaminants.

New legislation passed in Ohio in 2014 added ‘recycled water’ as a source for private water systems serving fewer than 15 service connections or 25 people on average. An on-site DPR pilot study was run from 2013 through 2016, and the system is now indefinitely approved as a potable water source for the office building that it serves. Following an initial testing period with purified water discharged to the septic system, the water has been plumbed into the building since 2014 and approved for all indoor uses including drinking and cooking since 2015. Extensive testing overseen by regulators and reviewed by an international panel of water experts demonstrated the excellent quality of the purified water and reliability of the advanced water treatment process. To date, this on-site DPR system has reduced dependence upon the well and volumetric loading to the septic system by upwards of 1.5 million liters.

Adam Arnold, MASc, Tangent Company, Chagrin Falls, OH
Adam is the Process Engineering Manager at Tangent Company and Member of the AWWA Water Reuse Committee. He holds Bachelor’s and Master’s degrees in Environmental Engineering from the University of Waterloo in Ontario, Canada. Following his graduation in 2008, he worked as a consulting engineer for three years designing municipal water and wastewater infrastructure. Over the past six years, Adam has led the research and process engineering groups at Tangent in developing and testing products for onsite sewage treatment and water reuse. He was also the lead designer for the onsite DPR system that is the focus of this presentation.


Philip Schmidt, PhD, AStat, Philip J. Schmidt Technical Consulting Inc., Guelph, ON, Canada
Philip Schmidt has a Bachelor's degree in Environmental Engineering and a PhD in Civil Engineering, both from the University of Waterloo. He is also accredited as an Associate Statistician by the Statistical Society of Canada. His doctoral and post-doctoral studies focused upon statistical analysis of quantitative microbial data and microbial risk analysis applied within the general context of drinking water. He has also carried out statistical research on dose-response relationships for several waterborne pathogens. He has worked with Tangent Company on on-site direct potable reuse since 2013, focusing upon risk assessment to assure and verify the safety of the technology.


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National Ground Water Association
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Websites:

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