When most Clovis residents turn on the faucet at home, they don’t question whether the water pouring into their glass is safe to drink.
That’s probably because Clovis has rarely had problems with water sanitation in the past. But what people don’t see is the behind-the-scenes work that ensures that water in Clovis homes is safe to drink.
The Roundup spoke to Clovis Water Production Manager Leon Penney and Clovis Assistant Public Utilities Director Paul Armendariz to get a peek into how Clovis treats our water.
Armendariz said Clovis gets water from three main sources, which include groundwater, surface water and recycled water.
Only surface water and groundwater are safe to drink, but both must be treated to remove pathogens and contaminants.
Groundwater is free of pathogens, but must be treated for possible contamination because of past activities that may have affected the soil, such as farming. This is carried out by using activated carbon, a black, charcoal-like substance that absorbs contaminants present in ground water.
Armendariz said out of Clovis’ 35 active well sites, six use activated carbon.
“We have six out of our 35 active well sites that have activated carbon. The other 29 active well sites – there is no additional treatment on there, it’s good clean drinking water with the addition of chlorine,” Armandariz said.
Surface water, on the other hand, is harder to treat because it contains harmful pathogens that are resistant to traditional treatment methods.
“There are two organisms that are present in our surface water that we are concerned with and that is Giardia and Cryptosporidium. Both of those pathogens cause severe acute diarrhea and intestinal distress. If you have a compromised immune system it can kill you,” Penney said. “The reason we are concerned about those two organisms is because they are chlorine tolerant. They can sit in a chlorine bath for up to two months.”
To remove these potentially deadly microorganisms, surface water is treated at the City of Clovis Surface Water Treatment Plant on Leonard Avenue, south of Bullard Avenue. Armendariz said the plant is designed to treat about 22.5 million gallons – more than 851 million liters – of water per day.
First, a specialized chemical called a coagulate is added to the water. This enlarges the pathogens, making it easier to filter them out.
Penney described the process in more scientific terms, “A coagulate is a specialized chemical that will combine particles that are in the water. We use a Polyaluminum Chloride. It has a very positive charge to it and most of the particles in water have a negative charge because of the chemistry of water. So your viruses and your silt and your bacteria usually have a negative charge on them and this molecule attracts those to it so it makes small things larger, it combines a lot of things into a larger particle. The larger the particle the easier it is to filter out.”
Next, water is sent through a special membrane that is made out of thousands of tiny hollow fibers that are about the size of a piece of spaghetti. The membranes fibers, which are made out of a special plastic called polyvinyl fluoride, contain pores that are .0001 millimeters in diameter. That is small enough to filter out 99.9 percent of microorganisms and pathogens.
“When the plant was being designed, they came up with this particular technology to remove those organisms (Giardia and Cryptosporidium) and they are not part of the picture as far as disinfection is concerned. They are completely eliminated,” Penney said.
After passing through the membrane, the water is chlorinated and stored in a tank. Once enough time has passed to allow the chlorine to kill any remaining microorganisms, the water is safe to drink.
The California Division of Drinking Water rated the Clovis Water Treatment Facility as having 4-log (99.99 percent) removal of viruses and pathogens. The facility is so advanced that the state allows it to operate unmanned for 12 hours out of the day, Armendariz said.
Penney said the workers at the plant are the first to drink water after it is treated.
“We are the first customer at the plant so we are very conscious of making sure that water is safe to drink because we consume it,” Penney said.
“Our job is only noticed when you fail,” he continued. “So we try never to fail, but we are not very noticed because everybody takes it for granted that you turn on the faucet and the water is there and available.”