by Sheryl Hamlin
California Water Boards held a webinar to announce the beginning of Public Comments for the proposed plan for Direct Potable Reuse (DPR) of wastewater. The comment period ends on 6/25/2021. Comments should be sent to [email protected].
The source of the documents is located at https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/direct_potable_reuse.html.
The webinar may be viewed here: video
The four panelists are shown below.
History and Theory
Randy Barnard said that in theory the introduction of recycled water into drinking water is achieved by controlled regulation of the two. He then went on to discuss California legislation starting in 2016 which authorizes research for DPR (Direct Potable Reuse). Protecting public health is essential. The systems must have the ability to take corrective action within minutes if problems are detected. He said that the DPR Framework changes 100 years of Public Health Policy.
DPR Framework Sections
Speaker Jing Chao said there are 27 sections in the DPR framework. There is a new Article 10 under Title 22 which is Chapter 17 having to do with Surface Water. This is important and will be shown in the scenarios slide. A level 5 AWT (Advanced Water Treatment) operator is required and additional coursework in advance treatment.
Four Scenarios are under consideration: 1) send AWTF (Advanced Water Treatment Facility) water to raw water augmentation facility such as a small pond or reservoir, 2) Send AWTF water to pipeline or aquifer, 3) Send AWTF water to tank to feed the SWTF (Surface Water Treatment Facility) and 4) Send AWTF directly to the end user drinking water distribution plant. The following chart shows all four entities with one path from option 1.
DPR Scenarios Option 1
Variations on these scenarios include potable and non-potable scenarios.
Effective pathogen control includes: real-time monitoring, redundant treatment, validate treatment train to monitoring for each treatment, and real time control for each treatment that responds accordingly.
He said the goal is 1 in 10,000 infections per year. He said nothing about death rates.
The three measurements are virus, giardia and crypto, all shown as log reductions. Here is information on illness from crypto and giardia: report.
They must identify all pathogens, he said, and understand how they work. He did not elaborate on virus. And there will be new SCADA systems for pathogens..
There must be a risk assessment, he said, for contaminants in the sewer shed such as chemicals that pass through Reverse Osmosis. He gave an example from Orange County where Acetone which was being measured shot up for some period of time and was sent to the drinking water. He did not indicate the length or the seriousness of this breach of operations.
After the comments period, all material will be sent to an EXPERT PANEL for review consisting of these types of skills.
DPR in the United States
Although not discussed in the webinar, several states, notably Texas and Arizona, both drought states, have legalized DPR and have pilot projects. Note that the Arizona Framework was approved in 2018 pre-covid. And the California legislation as mentioned above, was also approved pre-COVID. Scottsdale was the first to receive a DPR permit in 2019. Texas started DPR in 2014, again this was pre-COVID. Read here about Texas and DPR.
To watch the video click here.
Note that California gave a multi-million dollar grant to help with this project. Read about that here.
To read about the author, click sherylhamlin dot com