tank 40 is transferred to the carbon adsorber 26 as it is needed additionally the carbon may be transferred directly from quench tank 38 to the carbon adsorbers 26 without passing through fresh carbon tank 40 the exhausts from carbon regeneration furnace 36 are released from a stack 42 and are also transferred to after burner 44 the output of after burner 44 is cooled in process cooler 46 and then ejected through stack 42 as previously indicated it is imperative to the present invention that the required procedures be carried out in the proper sequence therefore the chemical neutrilization must be carried our prior to both the carbon adsorption and biological treatment steps and the carbon adsorption must preceed the biological treatment the significance of this feature of the invention will be further appreciated by considering the following data table 3 gives the composition of a typical effluent before treatment according to the present invention table 3______________________________________item maximum average______________________________________volume 1 69 million gallons 1 33 millioncolor 8000 apha units 6350 aphaph 1 6 2 3toc includes nitro benzene 585 ppm 377 ppmbod 540 364cod 1648 1047suspended solids 170 64dissolved solids 4248 3022mercury 1 23 0 22iron 21 5 9 0chromium 1.