The invention relates to a method for treating dangerous liquids for dumping in situ in a plant having an electrical panel (1) with an automaton processor, comprising the following steps: collecting in accumulation tanks (2); evaporating, in an automatic filling evaporator (6), via internal or external heating; condensing in a condenser (7), in direct or indirect contact with the vapour of the evaporator (6), converting said vapour into distillate; neutralising via reagents, in a neutralisation reactor (8), to a pH controlled by a pH and conductivity probe (14), with pH+ and pH+ reagents; filtering the waste via an active carbon filter (9) and dosing disinfectant therein, before expulsion via the drainage outlet of the sewer (32); safety disinfecting with ultraviolet light (17); and taking samples of the waste, by means of the sample-taking tap (16) provided before the outlet of the sewer (32).
