Direct Potable Reuse – Are Operations Ready?

Many water agencies in the United States and around the world have been turning to the potable reuse of municipal wastewater, either directly or indirectly, to help meet growing demands. Direct Potable Reuse (DPR) is the supply of highly treated reclaimed water directly to a drinking water treatment plant or distribution system, with or without an engineered storage buffer. This differs from Indirect Potable Reuse (IPR) which is already practiced in many areas of the US and involves the inclusion of an environmental buffer (such as a lake, reservoir or aquifer) prior to arriving at the intake of a drinking water treatment plant. There are a number of potential benefits of DPR relative to IPR, including reduced energy requirements, reduced construction costs and reduced operational costs. DPR may even provide an opportunity to allow potable reuse in situations where a suitable environmental buffer is not available for IPR.All water treatment facilities require a high level of reliability to ensure water is delivered to an acceptable quality and the risk to public health is minimized. This importance is underlined in the case of DPR, where the real risks of higher contaminant levels in plant feed water (e.g., during epidemics or after industrial accidents), along with perceived risks associated with public perception of reuse, require a high level of operational certainty. Consistent and assured levels of reliability can be met only with a holistic asset management framework including a robust design, effective and transparent operational management, a carefully managed maintenance strategy, and proven response procedures. The plant must be designed correctly, it must be operated well with realistic and practical demands on operations staff, and the assets and infrastructure must be maintained in a highly reliable condition.As the perceived “human element” in the process, operations must have robust and reliable operational plans, systems, and processes to ensure safety and reliability - essential elements for the advancement of public acceptance of recycling for potable use. Relative to existing water and wastewater treatment systems, operations teams are under much greater scrutiny for performance, and must therefore have adequate training and certification processes in place to provide a framework for developing and evaluating the necessary skills for successful operation and management of water recycling systems.This paper will present some of the work of Watereuse Research Foundation Study (WRRF 13-13 - Development of Operation and Maintenance Plan and Training and Certification Framework for Direct Potable Reuse Systems, which outlines an Operations and Maintenance Framework for DPR.