How It's Made: Septic Tanks

[MUSIC PLAYING] NARRATOR: Septic tanks are the perfect sewage treatment solution for houses that aren't connected to a sewage network. The tank collects and treats domestic wastewater using a bacterial process to decompose waste. It filters the dirty water before recycling it back into the ground. Septic tanks are usually made of concrete and have access covers on top. The waste treatment process takes place in separate chambers inside the tank. Steel bars called rebars reinforce the concrete structure of the tank. A welder assembles the rods to form a cage, then he spot welds the rebar with a mid welding torch. The welded cage will maintain the structural integrity of the concrete septic tank. The welder measures the cage's diagonals to make sure it's straight. Next, the worker places rebar spacers to keep the cage centered in the mold and leveled on the floor. A crane lowers the cage into a custom formwork made of high strength steel plates. Workers close the walls around the form and secure them in place with heavy duty locks. The crane lowers machined steel cores to form the interior walls of the tank chambers. A rigid plastic tube is inserted inside a rubber sleeve to create a flow hole between chambers. Using an acetylene torch, a worker cuts holes in the rebar for access openings. The mold allows concrete to flow over the rebar and inbed the access opening covers in the septic tank lid. Workers pour over 1,300 gallons of wet concrete into the mold. They use a stick vibrator to eliminate air pockets and level the walls with the putty knife. Next, they mix more concrete and pour it over the top slab rebar. Concrete blocks are used to keep the plastic covers from floating in the wet concrete. While one worker pours the concrete in the mold, the other consolidates the mixture with a vibrating stick. Then a worker levels at the top of the slab with the trowel. Once the concrete tank has cured, workers strip the forms. They removed the concrete tank using an overhead crane and a compressed air system, which forces the mold away from the concrete tank. The crane takes the strip core away for cleanup. A worker brushes the top of the walls and sweeps the floor inside the tank then he applies a butel rubber tape around the top of the exterior wall. This forms a watertight seal between the tank and the lid. An overhead crane lifts the lid out of the formwork and brings it to the tank mold. The crane slowly lowers the lid onto the tank. Workers keep it align to make sure it seals properly. Then they label the tank to indicate its capacity. Next, the mold is opened, revealing a finished septic tank. The rubber sleeve molded into the wall ensures a watertight connection between the pipe carrying waste from the home and the tank. This tank is now ready for delivery. They set the tank in the ground at the client's home using a radio remote controlled knuckle boom crane. A septic tank like this will provide a three bedroom house with a fully independent sewage system. [MUSIC PLAYING]

Channel: Science Channel

Views: 644,377

Rating: 4.9039345 out of 5

Keywords: How It's Made, production line, factory made, mechanical production, how do they do it, everyday items, how it's made full episodes, how its made, how it's made episodes, how to make

Id: CzaYAd3CX00

Length: 5min 23sec (323 seconds)

Published: Fri Mar 05 2021