| 摘要 |
<p>Activated sludge treatment of effluents from chemical factories, and partic. those from petroleum refineries, is effected in four stages: (1) primary treatment by sedimentation; (2) intermediate treatment by equalisation, pH adjustment, coagulation, oxidn. and filtration; (3) secondary treatment by aeration between the stages, biological oxidn., clarification, thickening and aerobic digestion; (4) tertiary treatment by coagulation/flocculation, filtration and adsorption on activated carbon. The refinery effluent enters the plant at the sump and then into a conventional separator where considerable quantities of oil and solids are eliminated. The chemical effluent enters at compartment of the multi-compartment tank. The mixed effluents pass through pipes, to press. filters and to the biological treatment section; this comprises four stages, a contract stage where the effluent meets the activated sludge, a clarification stage, a thickening stage and a digestion stage. The decomtanminated water then flows through a second battery of filters and is rejected into a watercourse. When rejected the evacuated water contains at least 5 ppm. of dissolved oxygen so that it does not therefore lower the quality of the receiving stream. Biological degradation is improved by keeping the temp. in the equalising tank at 32.2-37.8 degrees C.</p> |
