A process for the chemical treatment of an effluent containing at least one organic compound selected from the group consisting of an organometallic compound and an organic compound containing at least one of phosphorus, nitrogen and halogen, comprising treating the effluent hydrolytically for about 20 to 200 minutes at a temperature above about 100.degree. C. under a pressure above about 2 bars and a pH of about 1 to 14. Advantageously, a catalyst comprising activated carbon or kieselguhr is added to the effluent before the hydrolytic treatment and the hydrolytic treatment is carried out in the presence of ammonia or a primary or secondary amine. The organic compound may be an acid ester, a dye, or quaternary ammonium compound, a cyanide, a nitrile, a cyanate, an isocyanate, hydrazine, an organic derivative of hydrazine, an azo compound or an organometallic compound and the effluent may be aftertreated as with hypochlorite or H.sub.2 O.sub.2.