From The Editor | March 6, 2014

New Indirect Potable Reuse Regulations — What To Expect

By Laura Martin
@LauraOnWater

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Everyone is fighting for their fair share of water in drought-stricken California. The agricultural industry needs a large portion for growing crops and hydrating animals. Fishery owners and environmentalists are demanding preservation and replenishment of the California Delta to protect the salmon and other wildlife. And, of course, the residents of California can’t live without their portion for everyday use.

“Everyone’s needs are legitimate, but we don’t know if this is a five-year drought or a 500-year drought,” said Earle Hartling, water recycling coordinator for the sanitation districts of Los Angeles County. “Weather patterns are changing, the population is growing, and 75 percent of people in California live in the southern part of the state while 75 percent of the precipitation is in the northern portion of the state. There just isn’t enough water.”

Without enough new sources of water to go around, California is turning to water reuse.

In the upcoming months, the California Department of Public Health (CDPH) is expected to release regulations for groundwater replenishment of drinking water aquifers using recycled wastewater. These regulations are the first of their kind in California and unique in the U.S.

“Some other states have developed regulations for groundwater recharge with reclaimed water, but those developed in California are the most comprehensive,” said environmental engineering consultant James Crook, who has worked as an advisor to the CDPH.

Once adopted, these regulations will replace existing, less definitive regulations related to groundwater recharge of potable water supply aquifers, which were adopted in 1978 and consider water recycling projects involving groundwater recharge on a case-by-case basis. The current draft of the regulations, dated June 26, 2013, is used by CDPH to evaluate the acceptability of proposed recharge projects, said Crook.

“The draft CDPH groundwater recharge regulations have helped water and wastewater agencies and others understand what requirements must be met to assure that public health will not be compromised,” he said. “This has helped stimulate planning and implementation of indirect potable reuse (IPR) projects via groundwater recharge.”

There are two types of groundwater recharge/replenishment, explained Crook.

The first, surface spreading, involves tertiary-treated reclaimed water that is spread in basins, where it receives additional treatment. Then it slowly percolates through the earth prior to co-mingling with native groundwater. It is later extracted at a downgradient potable water supply well.

The second technique involves injecting recycled water directly into an aquifer used as a source of potable supply. 

The upcoming regulations will make it simpler for new groundwater recharge/replenishment projects to get started. Nearly 10 drafts for similar regulations have been considered by the CDPH since 1990. Though none were ever made official, the industry has attempted to comply each time, leaving many feeling like they were chasing a “moving target,” explained Hartling.

“Hopefully when we have these regulations in place, solidified, and adopted, we'll know exactly what to aim for in terms of treatment,” he said.

California has always been at the forefront of water recycling. The state was one of the first to run a groundwater recharge project using recycled water, with the Montebello Forebay Groundwater Recharge Project in Los Angeles County in 1962. California has more groundwater recharge IPR projects than any other state in the U.S.

Because of this long history, Hartling doesn’t feel the upcoming regulations will change public opinion of water recycling. 

“In a lot of areas of California, we’ve been doing it for so long that when people find out that their water is recycled they think, ‘Oh well, I’ve been drinking this for 50 years and I’m fine,’”  he said. “But when some of these additional projects come about, the new regulations and the additional treatment that will accompany them will go a long way toward removing some of the opposition.”

The exact requirements of the new regulations are still being determined. However, a draft written in June 2013 outlined some possible details.  According to the draft, all groundwater replenishment reuse projects (GRRPs) should utilize a treatment method that “consists of at least three separate treatment processes,” and meets, at a minimum, the requirements for filtered wastewater and disinfected tertiary recycled water.  Water that goes through advanced treatment is subject to less regulation overall. 

Certain contaminants must be monitored regularly before and after the recycled water is released into the environment. Prior to replenishment, at least one 24-hour composite sample to test for total organic carbon (TOC) must be taken each week. Results of the TOC monitoring performed cannot exceed 0.5 mg/L based on a 20-week average of all TOC results and the average of the last four TOC results.

Nitrogen samples, representative of the recycled municipal wastewater or recharge water applied throughout the spreading area, must be taken each week at least three days apart to assure average levels don’t  exceed 10 mg/L total  Each quarter, the recycled municipal wastewater must also be analyzed for chemicals having notification levels (NLs).

The draft also outlines requirements for how long recycled water must stay in the environment before being utilized by a downstream drinking water facility. As the draft currently stands, the water must stay in the environment for at least the period of time required for the organization in charge of it to respond and identify treatment failures and take action. This can be no less than two months. The draft also states that “two monitoring wells downgradient of the water entry point must be constructed  no less than two weeks but no more than six months of travel time away and at least 30 days up-gradient of the nearest drinking water well.”

Public notification of recycled water use could also be required by the new regulations. As the draft stands now, “the first downgradient potable water well owner and well owners whose drinking water well is within 10 years from the GRRP based on groundwater flow directions and velocities” must be notified of the recycled water use. Industrial, commercial, and residential communities within the service area that flows into the water reclamation plant must be informed of water reuse intent. The draft states that this is “for the purpose of managing and minimizing the discharge of chemicals and contaminants at the source.”

The regulations require more treatment for recycled water than may be necessary, said Hartling. But he doesn’t expect them to loosen up anytime soon.

“The health department was, probably rightly so, hesitant and concerned about using recycled water, so they were a little overly cautious,” he said. But once those regulations get in, it's very hard to make them less stringent.”

Once the recycled water recharge regulations are in place, the CDPH will begin working on the second half of the initiative — creating regulations regarding direct potable reuse (DPR). It is estimated that the framework for DPR regulations will be completed by 2016. Hartling believes DPR and ground water recharge will both eventually be a necessity in California, as well as other states that are short on water.

“We can put water underground, and that helps, but we can only put so much water underground,” he said “Eventually DPR will have to be the future.”

For more, check out Water Online’s Drinking Water Regulations Page

Image credit: "20142026-OC-DK-0006," © 2004 USDAgov, used under an Attribution 2.0 Generic license: http://creativecommons.org/licenses/by/2.0/deed.en

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