During asbestos sanitation works within closed rooms, it must be avoided that asbestos fibres leave the sanitation area and pose a threat to human health or the environment. Therefore, persons leaving the area of operation through a lock system, must take a shower before they exit. The deconta Water treatment system heats up the shower water und assumes the task of decontaminating (filtrating) the contaminated sewage water. The powder coated aluminium housing contains the electronic instant flow heater, the waste water pump as well as a 3 stage waste water filtration unit. The hot water outlet temperature of the shower water is infinitely variable with a max. flow rate of 10 liter per minute.