Be careful what you flush

  • Published
  • By Patti Kumazawa
  • Edwards AFB Environmental Management
EDWARDS AIR FORCE BASE, Calif. --  The Air Force observed Earth Day on Monday with a theme that focused on water reduction and reuse. Edwards has been reusing water from its wastewater treatment plant for well over a decade.

Because the base reuses water from the plant to irrigate the golf course and other green areas on base, residents and workers need to be careful what they allow to go down the drain or flush down the toilet.

Rags, snakes and an occasional toy flushed down a toilet are expected in the head works at the plant. Workers there can plan for that - large screen captures the big items before they reach the plant.

Workers can also plan for small rocks, sand and gritty material--another screen catches those items.

But, according to Rick Christensen, a base infrastructure engineer with the 412th Test Wing Civil Engineer Division, "No technology exists that can detect or keep hazardous materials out of the sewer if someone intentionally dumps something."

Hazardous material dumped into the sanitary sewer system can effectively shut down the wastewater treatment plant. "The wrong chemical coming through the system can kill the bacteria that make the plant work," Christensen said.

Built in 1996, the wastewater treatment plant at Edwards is like many city wastewater treatment plants throughout the world. Using processes similar to nature's, it is equivalent to sending sewage down an 80- to 100-mile-long river. The process takes what we flush and send down drains from the housing and the industrial areas on base and turns it into reclaimed water. "The water quality leaving the plant is so good we don't need to add any chemicals, other than a little chlorine," Christensen said.

Turning wastewater into reclaimed water takes several steps. But the most important part is done by hundreds of different bacteria species, many of which are probably living in your gut right now. These common bacteria create colonies, eat waste, reproduce and die in large open treatment tanks at the plant. This digestion process creates sludge that drops to the bottom of the large tank. The cleaner water moves to the next step in the process.

The sludge is removed, dried, tested and eventually becomes part of fertilizer after going through a composting process.

The most important job of the staff at the wastewater treatment plant is to keep the plant conditions perfect for the bacteria. The proper mix of oxygen, water movement, concentration of bacteria and correct balance of the bacteria species is critical.

"We maintain a steady environment for the bacteria," he said.

Hazardous materials dumped down drains can change that environment. "Fuels and oils float and block oxygen from getting to the bacteria," Christensen said. "Solvents and other chemicals change the dynamics of the living environment. Something poisonous will kill everything."

Christensen said the staff at the plant takes regular samples to check for hazards. "We sample this water just as much as drinking water is sampled. We look for many different things," he said. "But if something hazardous gets here, we don't usually see it until the plant's performance degrades."

"It's a major expense if the bugs die off," Christensen explained. "It takes time to build up a working bacteria population."

The plant processes up to 400,000 gallons of wastewater in a day, the reclaimed water is used to irrigate the base golf course and other green areas on base. Without reclaimed wastewater, base common areas would be a lot less green. "At Edwards, wastewater is not wasted," he said.

"You should never put any hazardous material down the sanitary sewer," said Larry Knight, a hazardous material/hazardous waste consultant at Environmental Management. Knight said hazardous materials should be returned to the facility's hazardous materials pharmacy, or HAZMART, when a worker no longer needs it.

"Some people don't understand the hazards of the materials they're using," he said. "Others just want to save a trip back to the HAZMART to turn it in." Knight said people who work with chemicals should think twice about dumping that little bit of leftover chemical down a sink. "Ignorance or laziness is not an excuse," he said.

Any hazardous material spill that affects a drain should be reported to Environmental Management customer service at (661) 277-1401.

Although the screen at the wastewater treatment plant catches rags and paper towels, these items should not purposely be flushed or sent down the drain. Cooking grease shouldn't be dumped down drains because it solidifies as it cools. These can clog the lines on the way to the wastewater treatment plant or cause damage to pumps in the sewage system.

Base residents need to keep hazardous material out of wastewater as well. Residents' cooking grease or oil should be collected in a container and thrown in the trash. Leftover mop water or similar household cleaners that are diluted with water can go down the sink. Other products depend on what it is.

"People should read labels and ask questions if they're not sure," said Steve Madoski, Environmental Management water quality manager.

Motor oil is collected at the Auto Hobby shop.

Housing residents who have household hazardous waste, such as leftover pesticides, motor oil, or cleaning supplies should contact the Housing Office at (661) 277-4506 for information on the proper facility to drop off the chemicals.

Base workers should contact their local HAZMART or call Environmental Management at (661) 277-1401 for more information.