How to Clean Water From Large Storage Tanks

Water can be cleaned from large storage tanks with a brush or hose.

Tanks that hold dozens, hundreds or thousands of gallons of water must be cleaned occasionally. And although there are many things in the world that are automated now and can be done by machines, cleaning water out of large storage tanks is not yet one of them. Accomplishing this task properly requires at least one person to scrub the tank's interior with a brush or high-powered hose.

Difficulty:

Moderately Challenging

Instructions

Things You'll Need

• Slope or ramp
• Long brush or high-pressure hose
• Detergent
• Fresh, clean water

1. Empty the tank. Most stationary storage tanks, such as the ones on large buildings, are fitted with washout valves that draw liquid from the tank's base. Drain the tank by opening the outlet valve. Or if the tank's the relatively smaller, mobile type that's transported on tankers, there should be an outlet valve in the back; open the valve with the tanker parked heading up a slope or ramp in order to drain and collect the water.

2. Scrub the tank's interior with detergent using a stiff brush or high-pressure hose. Leave the valve outlet open and use special care when cleaning the joints and corners, so that none of the old water remains in those areas. If they aren't cleaned well, traces of old water that may be contaminated with mold or foreign substances could taint the fresh water when it's mixed in.

3. Wash and flush the tank. Use a high-pressure jet or water hose to flush the tank out, if either of those tools are available. If not, fill the tank with warm or hot water and let it stand for 2-3 hours. Then drain the tank and collect the detergent-tainted water for safe disposal. If there are still residual traces of detergent detectable by sight or smell, continue flushing the tank until the traces are gone.

4. Clean the tank's pipes, hoses and pumps. Flush the wash-out pipes, the wash-out valves and other parts of the system with a mixture of detergent and hot water in order to remove any sediment deposits and other foreign material they might contain. Once they've been cleaned, flush the system at least once with clean water to remove any remaining detergent.

Tips & Warnings

• Professional sledge cleaners, divers and vacuum tank drivers are required

• Tanks will be taken out of service for a few days, to remove sediment

• Portable water storage tanks may use a different process

• Chlorine is the main chemical in cleaning and disinfecting storage tanks

• Liquids carried in tankers give off dangerous gases, even when the liquid has been removed.

• Corrosive liquid burns could happen.

• Always have a cleaner on the outside of access hatch to be there in case of accidents inside the storage tank while being cleaned.

References

• Wold Health Organization: Cleaning Water Storage Tanks