May. 10, 2018 Blending Rule Should Be Set by 2020

EPA announces new rule-making process for "blended" water

May 11, 2018 - On May 9th, EPA released a semiannual regulatory agenda that lays out plans for a proposal date – July 2019 – and a rule date – July 2020- for blending wastewater. This means that EPA will decide by July 2020 the circumstances under which treatment plants can reroute some stormwater and sewage around the required treatment process and then combine both with treated water.

On April 17, the U.S Environmental Protection Agency (EPA) announced a new rulemaking process surrounding the use of “blending” by water resource recovery facilities (WRRFs). Blending is used to manage high flow events at WRRFs while maintaining compliance. EPA announced their intent in this new process is to provide regulatory clarity and certainty with respect to the use of blending. Their goal is to help facilities optimize wastewater treatment during wet weather.

At the 2018 National Water Policy Fly-in EPA Assistant Administrator for the Office of Water David Ross made this announcement to wastewater and water reuse officials, stating “There has been a lack of clarity about this issue for decades.”

Rajendra Bhattarai, Division Manager for Austin Water Utility’s environmental and regulatory services and WEF Member, explained that water and wastewater utilities have been discussing the practice of blending for three decades and he hopes the EPA’s upcoming rule can help provide direction and when and how blending can be used. “It should not be abused, but only be used to when needed to avoid damaging the plant’s treatment systems, while protecting public health and environment,” Bhattarai said.

Rain and snowmelt can take WRRFs offline when excess water enters the wastewater collection system and exceeds a facility's capacity to treat all incoming wastewater. WRRFs often manage excess wet weather flow by routing some of the incoming water around the secondary (biological) treatment units and then “blending” it back in with secondary treatment effluent for disinfection prior to discharge. This, in turn, should allow an operator to avoid a possible shutdown or damage to the water treatment plant.

WEF will work to develop comments and engage with EPA on this rulemaking. (Bloomberg Environment, 5/9/18)