On an average long haul flight, there are over 1,000 flushes. Where does it all go?
Admit it! You’ve wondered what happens when you flush a toilet on a plane. Modern airplane toilets have suction so strong that your waste (including the smell) accelerates through pipes at the speed of a Formula One race car! Now that’s fast!
Airplane toilets used to rely on a large amount of blue sanitation fluid to keep the toilet flushing. These days, it still gets flushed but via an invention called the “vacuum toilet.” The toilet relies on strong suction and slick walls instead of blue fluid. The bowl is coated with non stick teflon. When you press the flush button, a valve opens, sucking down the contents of the bowl. The pipes carry their contents into large tanks that are stored underneath the main cabin.
The plane has to be emptied of human waste, typically on every landing. A grounds crew gentleman/woman rolls up in a vehicle called the “honey truck,” to collect the waste containers from the back of the plane. The honey truck has an 800-gallon stainless steel waste tank. A powerful pump can fill this tank in about ten minutes. Still, the driver must connect the pump to the aircraft by hand. He/she carefully connects the waste pipe to the release valve, making sure it is locked in place. If it is not locked properly, it will come flying off, spewing sewage everywhere. (It happens occasionally.) The honey truck operator wears gloves, of course. Once he is finished sucking sewage from a plane, he connects a flush pipe to clean out the plane’s waste tanks.
When the tanks are drained, the driver makes a run to the waste management facility that is usually located on the airport property. There, he/she drives the truck to the receptacle, opens a valve, and empties the truck. Video was posted by the Smithsonian Channel.