When Should DPR Water Enter The Mainstream?

The Water Research Foundation (WRF) has initiated a research project titled “Blending Requirements for Water from DPR Treatment Facilities” which, as the name indicates, aims to determine the optimum phase for incorporating highly treated direct potable reuse (DPR) water into the larger supply. There is potential for DPR to be introduced to the water supply before it ever reaches the treatment plant, blended directly into the mainstream distribution system, or added between the various plant processes.

The study is being led by Andrew Salveson, PE and water reuse chief technologist at Carollo Engineers.

“Through this project, we hope to understand the impacts on water quality due to blending of different purified reclaimed water with other raw and finished water supplies,” Salveson said.

The DPR blending issue is a question of how doing so will impact treatment operations. In pursuit of the answer, Salveson says his team will conduct an extensive analysis of water chemistry and perform pipe loop, corrosion, and biofilm studies. They will also evaluate the impact of blending on engineered storage buffer (ESB) design which could lead to conclusions regarding indirect potable reuse.

The project has an estimated completion date of late 2016 and Salveson was unable to comment on what his research has revealed so far. He did encourage a presumption that blending DPR water with the general supply would only raise the overall quality.

“That is certainly possible and our work will document it if that is the case,” he said.

For better or worse, the findings will inevitably contribute to the perception of recycled water and likely make a difference in its path to wide adoption.

“DPR is worrisome to many, mostly because it is new to many,” said Salveson. “Documenting water quality again, and again, and again, and performing novel research into areas such as blending, it’s intended to provide the industry confidence in the application of DPR... Doing this work, similar to other WaterReuse Research Foundation and Water Research Foundation work, is intended to educate our industry and the public on key water quality issues, many times demonstrating safety, and on occasion a new concern. We truly won’t know the impact on public opinion until we understand the result of this work.”

As Salveson indicates, this research project is one of many that are being conducted by leading industry minds into how, precisely, DPR water can or should be integrated into our everyday lives. WRF announced one such project simultaneously with Salveson’s. With such research occurring more frequently, it appears that momentum is building in favor of DPR.

A video featuring the two WRF DPR projects can be viewed here.