Massive Overhaul Improves Efficiency At California Treatment Plant
By Thomas Renner
Outside of the region where it located, many people might be unaware of the Metropolitan Water District of Southern California. Established in 1928, the “Met” is a regional wholesaler and the largest supplier of treated water in the United States.
Approximately 19 million rely on water from the district, which is more than 171 nations, the combined population of Switzerland, Ireland, and Norway, and 46 U.S. states. The district’s facilities serve residents covering 5,200 square miles, including parts of Los Angeles and San Diego. In a state that continually faces a water crisis, the Met’s importance to the community cannot be overstated.
With that many people depending on the Met, it is crucial that its systems and processes work at peak efficiency. A $38.5 million project at the Met’s Robert B. Diemer Water Treatment Plant will go a long way toward making sure that objective occurs.
The expansive scope of the project in Yorba Linda included a major overhaul of system components. The treatment plant began operations in 1963 but has not made any significant upgrade in improvement. With a treatment capacity of 520 million gallons per day, it is one of five water treatment plants in the extensive Metropolitan Water District Network.
“Water was not being wasted,’’ said Eber Luquin, project engineer for Environmental Construction, which dismantled the existing equipment and installed new components. “The equipment simply was not as efficient as it once was and water quality could be improved. The old, submerged mechanical equipment was coated in tar and some sealants used contained PCB properties.”
The project started in November 2018 and was completed in March 2021. Due to COVID-19 and other weather delays, the project took about four months longer than anticipated to complete. The end result, however, should guarantee that residents in the water-starved communities it serves have water that is safe for drinking, cooking, and any other use.
Complete Overhaul
The Diemer plant is one of the largest in the nation and has the capability to meet the needs of approximately 3 million people that live in the region. Water entering the 212-acre plant comes from two sources, a 440-mile aqueduct that is part of the California state water project and a 242-mile aqueduct that funnels water from the Colorado River.
The water is treated to meet or exceed federal and state drinking water regulations. Using advanced treatment technologies, increased monitoring, and adhering to the stringent laws and guidelines, the process ensures the water quality meets government standards. The Met performs about 250,000 water quality tests each year.
Due to the age of the facility and minimal replacement over the years, nearly every component needed to be replaced. That included flocculators, baffle walls, clarifier, effluent launders, drop gates, Weir gates, inlet gates, pipes of various sizes and material, sludge pumps, valves ranging from one-half inch to 42-inches, Smith Blair couplings, Victaulic couplings, and manual and electric actuators.
The work also included strengthening a filter control building, including reinforcement of interior concrete frames and filter decks and construction of new concrete shear walls. Teams also replaced 128 high-performance, rubber-lined butterfly valves and actuators, and replaced or modified structural support components, piping, mechanical equipment, handrails, and lights. Some hazardous material abatement was also required.
The Metropolitan Water District’s process includes ozone as a primary disinfectant. That step alone destroys a wide range of microorganisms and effectively removes unpleasant tastes and odors. Taste tests validate the process, as the Met’s water was selected the best-tasting tap water in the nation in the 31st annual Berkeley Springs International Water Tasting competition in June. The contest featured water sourced from 14 countries and 19 states. Metropolitan took top honors in the municipal water category.
Construction Challenges
The expansive project scope and size of the facility posed some unique challenges for engineers.
One task confronting Luquin’s team was installing effluent launders, where workers needed to solve issues regarding access and load restrictions at certain areas of the plant. Launders are an important part of the treatment process, as they help prevent waste materials from ending up in the water.
“We designed large crane pads that would not exceed 1,500 PSI (ground bearing pressure) with our given loads so that we could install launders,’’ Luquin said.
Teams also faced access issues in constructing concrete shear walls. “The shear walls were constructed in four quadrants underneath the filter beds and access was very restricted to each location,’’ Luquin said. “There was only ingress and egress. We had to get all of our materials through a small opening, 5-feet x 6-feet, and then had a 15-foot drop. This was considered a confined space, so we had many OSHA regulations to comply with.”
Accessing Flocculators
In any water treatment plant, flocculators are key pieces of equipment that help determine the amount of treatment water needs and the sequence in which chemical agents should be added. Readings from the flocculators can help water treatment plants operate efficiently. Flocculation is also essential in keeping the water supply clean.
Treatment plant workers will access flocculator equipment through stainless steel doors manufactured by The BILCO Company. The 10 single- and double-leaf doors are frequently used at water treatment plants due to their engineered lift assistance and safe, easy, one-hand operation.
“BILCO hatches were selected due to their dependability and reputation with the plant,’’ Luquin said. “The fact that these hatches are made with quality stainless steel material to the dimensions we required and have a drain port built in were important features.”
Corrosion, especially at water treatment plants, can dramatically reduce the life of floor doors and other equipment. BILCO’s doors are constructed with corrosion-resistant materials. They are also engineered with lift-assistance for easy opening, and an automatic hold-open arm locks the cover in the open position to ensure safe egress. Heavy-duty construction and a positive latching mechanism help prevent unauthorized access.
The project included the installation of 10 stainless steel floor doors manufactured by BILCO.
Drought Concerns
Water in California is a treasured and highly sought-after resource. There never seems to be enough to go around, and long-term droughts have dried up a number of reservoirs. The state experienced a six-year drought from 2012-2016, according to the California Department of Water Resources. In April, Governor Gavin Newsom announced several actions related to drought preparedness, as the state experienced its second consecutive dry winter.
The water shortage leads to economic and environmental consequences, including a shortage of drinking water and wildfire risks. The unpredictable nature of droughts exacerbates water challenges.
With those factors impacting the state, it is essential that water treatment plants in the Met’s portfolio operate as efficiently as possible. The massive renovations at the Diemer facility will help ensure that.
“I think it’s an essential lifeline for the people in Southern California,’’ Luquin said. “The supply from the Metropolitan Water District is a vital resource for smaller districts in the region. This project will help the system maintain peak efficiency.”
Thomas Renner writes on building, construction, engineering, and other trade industry topics for publications throughout the United States.