Abstract: Effluent containing organic impurities which are difficult to degrade is purified by oxidation in the aqueous phase at temperatures of 100.degree. to 310.degree. C. and under elevated pressure. This is effected by initially treating the effluent in a first stage with gases containing oxygen, but without the addition of catalysts, until the C.O.D. value has been reduced by 50 to 98%. The effluent which has received preliminary treatment in this way is subsequently treated, in a second stage, with an oxidizing agent stronger than oxygen, in the liquid phase and at the same, or at a higher, temperature, until the C.O.D. value has fallen to approximately 0 g/l.

Abstract: When explosive gases are introduced into a combustion chamber care must be taken that no pre-ignition occurs. To this end, the gas is spatially subdivided into discrete volume elements, for example by means of a bundle of tubes having an internal diameter which does not exceed twice the quenching distance of the explosive gases. Such a division ensures that the wall distances of the gas portions of one volume element are greater than their quenching distances.