EDH treatment plant boosts capacity
A year and a half of construction at a cost of $8 million and now the El Dorado Hills Water Treatment Plant has increased its capacity 33 percent.
But the biggest benefit of the Phase 1B upgrade is the eliminationof chlorine gas. The chlorine gas, used to kill bacteria, had always left El Dorado Irrigation District officials nervous. There had never been a chlorine gas leak, but being right next to Marina Middle School was a motivation for the district to find an alternative.
Instead of chlorine gas the revamped plant uses a 12.5 percent solution of sodium hypochlorine. It’s the same liquid that is used in swimming pools and spas. EID only needs to use dollops of it. It uses it in the water treatment cycle to kill off giardia and cryptosporidium. Then after the water is purified and ready to pump into the distribution center it gets a very small amount of chlorine to coat the distribution pipes to prevent corrosion and prevent the growth of organic life in the pipes.
EID sanitary health specialists test the water not only at the plant but at various points along the distribution system.
The water arrives at the treatment plant after being pumped 400 vertical feet from Folsom Lake. The lake may look clear, but the filters in the water treatment plant show there is turbidity in the water. That’s a fancy word for particles of dirt. The four pairs of treatment tanks begin to eliminate the turbidity by bubbling up the water to stir up plastic beads to which the dirt particles attach themselves. After that process the water is 95 percent treated, said plant operator John Beall.
EID sponsored a VIP tour of the El Dorado Hills Water Treatment Plant Oct. 20 when it was a mere two weeks after completion. The district is awaiting authorization from the state before it ramps up its full capacity.
Besides eliminating chlorine gas, one of the biggest additions to the plant is a really big water tank— 400,000 gallons worth. It holds raw water from the lake and really boosts the plant’s treatment capacity.
Current treatment capacity is 19.5 million gallons per day. The new authorized capacity will be 26 MGD, according to a brochure handed out at the tour. The design will handle 54 MGD, noted Drinking Water Division Manager Dana Strahan.
Though the plant serves El Dorado Hills, it may also serve water as far west as Cameron Park. EID General Manager Jim Abercrombie said that will be determined as part of a rate optimization study. Meeting Oct. 25, the EID Board of Directors approved a $279,875 contract to California Water Consulting to do 2,058 hours of staff time performing a water optimization study.
California Water Consulting, with a team led by Mike Prezzler and working with the advisory group, Citizens for Water, will study the the option of moving EDH pumped water to Cameron Park, the option of diverting water rights at a higher elevation than Folsom Lake, taping into the White Rock penstock where Sacramento Municipal Utility District left EID an access point as part of the 1962 El Dorado County Water Agency deal with SMUD. Other avenues of study include bringing more water to Sly Park via the Hazel Creek Tunnel that connects to the El Dorado Canal.
Additional areas of study include a possible reservoir on Alder Creek in conjunction with a powerhouse at Plum Creek and possible small hydro projects on Silver and Caples creeks.
Meanwhile an additional factor in the increased capacity of the El Dorado Hills Water Treatment Plant is a new feature —a recycling tank where water with extra turbidity is sent for recycling. Water is extracted from it and the solids are sent through a clarifier that reduces those leftovers to solids that are then trucked off to the El Dorado Wastewater Treatment Plant for treatment in its anaerobic digester.
All processes at the El Dorado Hills Water Treatment Plant are automated. Licensed water treatment specialists monitor the plant operation and water tank levels through El Dorado Hills by a computer system. Water testing is still a manual process that is used to guide what to add to maintain the pH balance of the treated water and insure its purity.
The maximum automation that came with the plant upgrade means that in about a week or two the plant will no longer be staffed 24 hours a day. Water use is lowest at night. The plant will change to one 12-hour day shift. A plant operator will be able to monitor the system from home on a laptop.
Altogether the district has spent $17 million in several different phases to improve reliability of the water treatment plant and meet new regulatory requirements. Adding to the reliability is 1.25 megawatt diesel generator the size of a single-wide trailer that will keep the plant and the computer monitoring system operating in case of a power failure.
Besides the plant upgrade EID boosted the capacity of its water main along Silva Valley Road, so it can handle the increased water delivery.
The El Dorado Hills plant is state of the art and will serve as a model when Treatment Plant No. 1 in Pollock Pines is upgraded and its chlorine gas replaced. with liquid chlorine. That treatment plant served El Dorado Hills with high mountain flume-carried water while the EDH plant was being rebuilt.