Figueroa turns 40

The Figueroa Avenue Wastewater Treatment Facility has now been operational for 40 years. It was built in 1970, and since then has treated over 85 billion gallons of raw sewage.

“There was a facility on site prior to that and what was here prior was a rudimentary screening process,” said Jeremy McCall, Treatment Plant Supervisor.

“They used it to take out the big garbage before they introduced it into the river. In 1968 they developed a plan, and the plant was built kind of how you see it today. It has been in operation ever since.”

Operating under very strict federal and state permits, the plant, one of three in the city, cleans over 80 percent of Yuma's wastewater, which is then discharged into the Colorado River.

“It is an interesting place to work and it is nice to contribute to our community to ensure that the water is clean. That is a good part for me,” said Ward Seibel, chief mechanic.

The smallest facility, Jackrabbit Mesa, and the newest facility, Desert Dunes, treat the remaining 20 percent of Yuma's wastewater.

“The purpose of this facility is to treat wastewater of its primary constituents and render it in a safe environmentally friendly manner before we introduce it back into the Colorado River,” McCall said. “It is wastewater generated form households and industrial and commercial processes.”

Before its completion in 1970, raw sewage water was simply filtered for large objects before going into the Colorado River.

“Prior to this it went directly into the river,” said Betsy Bowman, laboratory director.

“That was the standard,” McCall said. “The rules and regulations we operate under today weren't imposed until 1970 or 72 and refined through the years. Prior to the legislation act which took place in the early 70s, there were no standards. You were allowed to operate under your own accord.”

To ensure the water isn't negatively affecting the river, and to adhere to the strict rules, an on site laboratory headed by Bowman collects thousands of samples each year from each step in the cleaning process and from the river where the cleaned water is dumped to ensure quality.

Samples are performed to show compliance with the Clean Water Act, the Safe Drinking Water Act, the Arizona Pollution Discharge Elimination System and many other Federal and State environmental programs.

The Yuma Sun was recently given a tour of the facility to see it in action. Check out video of the tour on Yumasun.com.

When wastewater comes into the plant it first goes through the Head Works, which removes large particles greater than three inches.

Contrary to popular belief, most of the sewage treated isn't feces, McCall said.

“Predominately most of the wastewater that comes into the plant — you'd be surprised — its not something from a toilet. That is a very small use of it. We are seeing wastewater from people's showers, people's dishwashers and industrial processes that use water for cooling towers and what not. When you see the wastewater that comes into the plant it is not laded with material. There is just a small fraction of solids that we have to remove and treat.”

From the Head Works, the wastewater goes into pumps which hydraulically load the plant for a continuous flow. Then the wastewater is sent to grit removal to get rid of the sand in the water.

The water is then sent to large clarifiers which separate solids from liquid. The heavy particles are separated by sinking to the bottom.

“The water at the top is clearer and the bottom is bio-solid sludge,” McCall said.

The solids and the liquids then go on to separate areas in the plant.

The solids go into another clarifier where more water is squeezed out before going into a huge digester which decreases the amount of bacteria.

“It is like a stomach,” McCall said.

The bio-solid stays in the plant for 25 days before being given to area farmers for sub surface soil injection into fields of crops not intended for human consumption.

After being separated in the clarifier, the wastewater is still full of hazardous organic matter. To eliminate the unwanted waste, the plant cultures a special type of bacteria which then eats it.

The water sits in aeration tanks full of the worker bacteria for about 16 hours. It then goes to another clarifier to settle out the dead bacteria.

The water is then disinfected with an industrial bleach 10 times stronger than regular household bleach. So as to not pose a threat to the environment, the water is then de-chlorinated before being pumped into the river.

The water releases into an area teeming with vegetation and wildlife which doesn't seem to notice anything adverse in the water.

“Our responsibility to the community is to provide clean water and a safe environment so that we don't have any issues with someone going to play in the river downstream of our outflow” McCall said. “I think knowing the condition of the river in this stretch, I am very pleased with the quality of water we are discharging because it actually improves the water.”

The water must be clean because other communities down river rely on it as a source of fresh water.

“Our water is basically discharged into the river shortly before the Morales Dam, and that ends up as a drinking water source for our southern neighbors in Mexico,” McCall said.

Chris McDaniel can be reached at cmcdaniel@yumasun.com or 539-6849.