In Arizona, hard water runs through the pipes to the tap and is usually filtered through a reverse osmosis water softener, which removes calcium and magnesium with salts. Those chemicals are sent to wastewater treatment facilities where wastewater is treated for reuse.
Treated wastewater can be reused in watering landscapes like golf courses or as a resource in nuclear power plants like the Valley’s Palo Verde Nuclear Generating Station.
According to Mark Holmes, water resource manager for the city of Goodyear, their wastewater treatment facility is impacted negatively in their wastewater treatment process with a stream flow blockage caused by total dissolved solids and brine. Brine is a by-product that accumulates after groundwater-supplied reverse osmosis systems and water softeners filter out chemicals and then relay the used water back to Goodyear’s wastewater treatment facility.
David Perry, executive director of the Arizona Water Quality Association, said well over 50 percent of homes in the Valley have water softeners. “We did a survey several years ago in the Phoenix area, and it came out to 55 plus percent,” he said.
Perry explained that the reason why more than half of Valley homeowners have water softeners is because hard water is hard to clean with.
“I would imagine a smaller percentage of people are concerned about wastewater, particularly because it is not something that the general public thinks about,” said Erin Driver, graduate research assistant at Arizona State University.
“Arizona currently has over 100 treatment facilities that reuse the water right now,” said Peter Fox, senior sustainability scientist at the Julie Ann Wrigley Global Institute of Sustainability at ASU.
Wastewater reuse has ever-changing controversial terminology due to the goals for the future of recovering not only water but according to Fox, recovering nutrients for fertilizers too from the wastewater.
“If you even call it a wastewater treatment plant, somebody is probably going to scold you and tell you, you should be calling it a water resource recovery facility, because that’s what it really is,” Fox said.
Driver says that in the past, many treatment plants performed at a lower level of treatment, which is recognized as a primary treatment only.
Nowadays in the Valley’s multiple and technologically sophisticated wastewater treatment facilities treat a larger amount of wastewater due to population growth. “The issue is in the return to the waste water system,” Perry said.
“Definitely we’re impacted, wastewater treatment plants are chemically impacted by total dissolved solids,” Holmes said.
“Any uses of water tends to add sodium and salts to the water before it is returned the wastewater streams, so the concern is the difference the salt level of the water leaving the treatment plant compared to the salt level of the water returning to the wastewater treatment plant,” Perry said.
“We are actively working not only to advance removal technologies in the plant but to understand the consequences of releasing certain compounds into the environment,” Driver said.
“Wastewater contains a lot of more chemicals than most people realize and sometimes those chemicals can pass through the treatment facility,” Driver said.
Driver gave an example of this with triclosan, an antimicrobial compound banned by the FDA earlier this year, which is found in soaps, cosmetics, deodorants and first aid supplies. Driver explained that evidence from the 2000’s showed that the antimicrobial compound interferes with hormones in the body, accumulates in tissues of humans and organisms, is toxic to aquatic environments and disrupts the good bacteria in wastewater treatment plants. The removal of triclosan from treated wastewater is a matter that will require further research in the future; the ban will go effect in 2017.
However, the issue of total dissolved solids and brine accumulation in Goodyear’s wastewater treatment facility is currently being addressed. Goodyear’s water resource management has decided to fill a wetland facility with their treated wastewater that will use the brine to blend an appropriate balance of salt water while also removing harmful chemicals such as arsenic and selenium, to create a recreational area for Goodyear’s community. The wetland will also be a steady supply of water to the Gila River.