On Tuesday October 13th 170 water professionals gathered in Downtown Los Angeles for a drought symposium sponsored by the Los Angeles Basin Section of CWEA and WateReuse California. Speakers provided technical updates on water supplies that agencies can tap into right here in the LA Basin – including recycled water, desal and stormwater. The theme of the event was building a more resilient and reliable water supply for LA by embracing the one water concept.
Increasing the Use of Recycled Water
For the Water Resources Control Board’s Division of Drinking Water ensuring consistent and reliable recycled water regulations are a key focus as more projects enter the final planning stages according to Kurt Souza, a Deputy Director of DDW’s Southern California office. On April 1st the Governor implemented mandatory conservation and required regulators to speed the permitting process for local water supply projects including recycled water projects.
This includes looking at new regulations for surface water augmentation and direct potable reuse (DPR).
“The supply situation is serious. Reservoirs are at record lows and that’s going back to the 1880s.” – Kurt Souza, SWRCB DDW
“In the Central Valley, recent groundwater levels are more than 100 feet below previous historic lows. There is good news – the Governor set a goal of saving 1.2 million acre feet of water and as of August we are half-way to the goal. We’ve saved 612,000 acre feet so far, pretty incredible,” said Souza.
Last year DDW assembled a panel of experts to look at surface water augmentation and once that report is complete shift to analyzing direct potable reuse regulations (DPR). A draft surface water augmentation report will be issued in Spring 2016 and the process will start for public workshops, CEQA review and State Board consideration. For DPR regulations, a report will be issued around September 2016, according to Souza.
Souza emphasized the key aspects of protecting public health are the standards for the people who design and operate IPR and DPR facilities.
“For IPR projects we’re looking at the operators of these advanced treatment plants. Where will we get these highly specialized operators?” he asked. “Facilities will need to have strong O&M plans, optimization of each treatment step and good maintenance practices. I’ve walked into 20 year old plants that look great – like new – and I’ve walked into 20 year old plants that look 50 years old, not so great. We cannot allow poor maintenance.”
The next speaker, Bryan Trussell of Trussell Technologies summarized the research of Dr. Rhodes Trussell, a world-renowned recycled water expert based at the firm’s Pasadena headquarters.
“I would argue this drought is a harbinger of our future. In the last century we built projects to store and move water and we pumped it out of the ground. Our water needs have reached the point where those solutions are all tapped out.” – Bryan Trussell
Why reuse water in the urban environment? According to Trussell it comes down to location, cost and technology. The water is already here as highly purified and clean wastewater discharged from local treatment plants. According to one estimate 1.5 million acre feet (488 billion gallons) is used once in California, treated and then discharged into the ocean each year. Recycling water is also one of the most affordable sources of water and treatment technologies are already proven and available to produce highly pure and healthy water.
There’s another reason reuse is feasible for urban supplies – it’s already been occurring for centuries, we just never paid attention. If you look at two towns pulling water from a river for drinking – town A is upstream and will use the water and discharge its purified wastewater back into the river. Downstream town B takes water out of the river, cleans it and pipes it into their drinking water supply. A portion of town B’s water supply is treated wastewater from town A. This is known as “defacto reuse,” said Trussell.
How common is defacto reuse? A 1980 EPA nationwide study found about 1% of city drinking water supplies include reused wastewater from upstream cities. A 2008 Arizona State University study updated the EPA research and found 5% of the water supply in 17 cities is treated water from upstream cities and during droughts the percentage for some cities rose to 33% of their supply.
“I think our national experience with de facto reuse shows us the question is not ’do we or do we not engage in reuse.’ It’s common and appears to be increasing,” said Trussell. “It’s more as we move into this new water era, how do we make sure reuse practices continue to be safe.”
Trussell emphasized the focus must be on protecting public health and described four standards our profession needs to embrace – reliability, redundancy, robustness and resilience.
- Reliability – consistently serving customers the highest quality and healthiest water
- Redundancy – going beyond the minimum requirements, adding more treatment than necessary to provide a substantial safety factor to prevent errors
- Robustness – using multiple treatment barriers to remove all contaminants
- Resiliency – systems designed to detect errors early on and adapt to failures
“Potable reuse will play an important role in California’s water supply in the decades ahead,” said Trussell. “If we make good choices, California will continue to be a great place to live and will have a resilient economy.”
Ocean Water Desal Begins Again in Southern California
In the next presentation Peter MacLaggan, a Senior Vice President for Poseidon Water, described the company’s new 50 million gallons per day ocean water desal facility in Carlsbad. Construction is complete and the plant is starting to produce small amounts of water during the start-up phase. The facility will start delivering water before the end of the year.
The plant takes in 2 gallons of seawater and 1 gallon of clean drinking water comes out. The process involves a water intake structure shared with the neighboring power generation facility. Water then goes through deep bed filtration, micro filtration screens, reverse osmosis and calcite filters. The clean drinking water is pumped 10 miles up to a trunk line which flows into a San Diego County Water Authority reservoir. The removed salt water is routed back to an ocean outfall, also shared with the power plant. Diffusers allow the brine to remix with the open ocean.
MacLaggan emphasized the water sector has learned a lot about desal and those lessons were applied to the design of the Carlsbad facility. “There are 15,000 reverse osmosis plants around the world, producing 1.5 billion gallons of clean water every day,” he said.
He also pointed to new technologies inside their facility designed to lower the demand of the desal process. “The Carlsbad RO process is unique in that it uses energy recovery pumps to recover energy and lower energy demand at the facility by 46%.”
For MacLaggan the discussion about the future of recycled water is beyond a doubt. “”We’re going to be recycling all of our water to reuse it, then look for more local supplies like brackish water, and then to ocean desal. That’s our water future,” he said.
Capturing Stormwater in the City of LA
According to Shahram Kharaghani from the City of Los Angeles Stormwater Division – the Mayor has set ambitious goals to move the City to more local supplies of water. In October 2014 the Mayor signed an executive order requiring City departments to work together and reduce imported water by 50% by 2025. In addition, the Mayor’s order says 50% of the City’s supply should come from local sources by 2035.
City agencies like the DWP and LA Sanitation are working together with stakeholders to develop the “One Water Plan” – a series of steps and projects that will lower the need for imported water and increase the use of groundwater, stormwater and recycled water. According to the plan, stormwater will make up 4% of the supply – approximately 25,000 acre feet per year.
“The City of Los Angeles One Water program discovered during our research that a $1 million investment in water infrastructure generates $22 million in economic activity. We’ve done a lot of planning, now we need the funding so we can start to build these joint venture projects.” – Shahram Kharanghani
Kharanghani said the One Water Plan estimates $100 to $150 million is needed each year to invest in LA stormwater projects in order to meet the stormwater reuse goals. Currently, there are no funding sources available that can provide that level of investment, although the City is looking at the Proposition 1 Water Bond for possible funding.
The event was organized by
LA Basin Section of CWEA and WateReuse California
The event was sponsored by: Arcadis, Carollo,
Hazen & Sawyer, and RMC Water & Environment