A bus toilet works differently than a home toilet does. A bus toilet does not use water, and it is not hooked up to a sewer. On a bus, urine and feces are held in a holding tank. Bus toilets use a blue formaldehyde product to mask the odor of urine and feces.
There are two main types of bus toilets. One type has flap in the toilet that closes to hide the view of the holding tank. The other type does not have the flap, which leaves the holding tank in view.
Toilet with a Flap
A bus toilet with a flap has a handle for flushing. When the toilet is flushed, the blue formaldehyde fluid swirls through the toilet. The flap opens, and the human waste and formaldehyde go into the holding tank.
Toilet without a Flap
A bus toilet that does not have a flap doesn't need to be flushed. These toilets do not even have a handle for flushing. Since there is no flap covering the holding tank, urine and feces drops straight into the tank when a person uses the toilet.
The blue formaldehyde product helps to control odors. A vent in the bus bathroom also helps to control toilet odors. The vent in the bathroom leads to the outside of the bus. Odors are pulled through the vent to remove odors from the bus bathroom.
Emptying the Holding Tank
The holding tank needs to be emptied periodically. Bus operators usually empty the holding tank after every trip to keep odor down. To empty the holding tank, one end of a sewer hose is attached to a fitting located on the outside of the bus, and the other end is attached to a sewer. A button on the bus is pushed to open the holding tank which allows the blue formaldehyde--and the urine and feces--to empty from the holding tank. All of it goes through the sewer hose and into the sewer. After the holding tank has been emptied, the sewer hose is removed. A button is pushed to close the holding tank, and new blue formaldehyde fluid is put into the tank.