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).
