Wash racks recycle thousands of gallons of water
September 7, 2012
KANDAHAR AIRFIELD, Afghanistan--401st Army Field Support Brigade personnel using five self-contained wash racks at AFSBn-Kandahar have been washing vehicles nearly around the clock since March 30 and are saving thousands of gallons of water daily.
The wash racks are part of a military construction project being completed by the Army Corps of Engineers and are critical to preparing vehicles for retrograde. They are now configured to recycle 80 to 85 percent of the water they use. Since each wash rack uses between 400 to 800 gallons of water daily, savings of money and resources are significant.
The wash racks are used to thoroughly wash vehicles being retrograded to a source of repair in the United States. A water recycling system was included in the design of the wash rack units but initially they were only recycling about 5 percent of the water being used, said Shawn Huebner, USACE construction representative.
"The Afghanistan Engineer District-South Kandahar Area Office lead engineer, Dan Johnson, asked me to evaluate the water recycling system and look for ways to improve the volume of water recycled," said Huebner. "Bringing the wash rack recycling systems up to a more efficient operating status was a challenge. I had to identify a better way of capturing the water for recycling and troubleshooting low-water pressure issues with the pressure washer."
Huebner said he decided to use a catch basis system similar to those found in septic tanks, but the project was a team effort.
Water drains into a gutter located on the side of the wash rack and empties into the first catch basin chamber where mud and debris settle to the bottom of the chamber. When water enters the first chamber of the catch basin, mud settles and the water level rises and flows into the second chamber of the catch basin where a submersible pump is located. When water reaches a certain level in the second chamber, a float activates the submersible pump.
The water then enters piping which has an inline screen filter. The water is pumped through the filter then into the VEW system (Vehicle Equipment Wash) which has three parts.
Step 1 of this system is the Oil/Sludge Water separator (OWS) tank which has two chambers. The first chamber has eight Flopak Coalescing Media, one secondary coalescing media and one oil skimmer and sludge pit.
The main purpose of the first chamber is to separate oil and any petroleum products from the water. When oil rises to water surface it is captured by the oil skimmer. Heavier materials (sludge) settle in the sludge pit.
The water travels over a weir to the second chamber. In the second chamber, the water is pumped through a two-bag filter canister system. The bag filter canisters filter sediment that did not settle in the sludge pit.
The final step is the AQAM system (Alky Quatemary Ammonium Montmorillonie) tank. This tank filters trace amounts of petroleum/hydrocarbon product. When water has completed step three, it is pumped into the water storage tank and ready to be used with the pressure washer.
"Major Frederick Cummings, USACE officer-in-charge, worked with the 401st to coordinate our efforts and keep them informed. Jack Ratliff, Reginald Terry and Dan Fink are the USACE engineers that I worked with to identify a workable septic type system," said Huebner. "Gary Yeatts, our quality assurance representative and I ensured that the system was built properly. The pressure washer manufacturer helped us solve the water pressure issues -- we simply re-plumbed the water supply at the storage tank to the pressure washer and that problem went away too."
Ollie Jackson, project engineer and contracting officer's representative ensured contract requirements were being met and provided oversight where needed, Huebner said.
Huebner said the last step was training the workers who use the wash racks on daily maintenance and troubleshooting wash rack issues.
Vehicles being prepared for retrograde to the United States are thoroughly washed to comply with standards set by the U.S. Department of Agriculture and Department of Defense designed to ensure vehicles entering the country are free from soil and agricultural hazards. Particular attention is paid to removing soil from a vehicle's undercarriage, fender wells, axles, springs, bumpers, wheels and recessed areas.
Depending on the vehicle type, washing a vehicle being returned to the United States takes between two to 12 hours said Thomas Gloss, 401st AFSB support operations deputy.
Recycling water conserves a precious natural resource in addition to saving money and other assets. Recycling water means fewer trucks and less fuel is needed to deliver water to the wash racks. Also clean water being processed for use on the installation can be used for showers, laundry facilities and other requirements.
The 401st AFSB operates wash racks at all redistribution property assistance yards and is in the process of acquiring more racks that can recycle a high percentage of the water used to wash vehicles.