Chemicalplants produce benzophenone, benzotriazole, p-nitroaniline and other chemicalproducts. The COD concentration of wastewater produced is as high as 8,300mg/L,the composition is complex, BOD5/COD is less than 0.1, and it is difficult todegrade.  The wastewater also contains organic substances that are toxicto microorganisms.  In addition, the content of ammonia nitrogen and saltin wastewater is also very high.

Thewastewater cannot be directly treated by biochemical method, and thebiochemical treatment can only be continued after physical and chemicalpretreatment.  For this reason, the following biochemical treatment iscarried out only after three steps of pretreatment including alkali addition,blowing off ammonia nitrogen, evaporation, crystallization and desalting, andthen micro electrolytic cell.  The process flow is shown in the figure. The effluent COD of this process is less than 150mg/L, and the removal rates ofsalt and ammonia nitrogen are 98% and 93% respectively.

Treatmentof Synthetic Rubber Wastewater by Hydrolysis Acidification-Biological ContactOxidation

Industrialwastewater from a synthetic rubber factory: COD800mg/L, with goodbiodegradability.  Therefore, the biochemical method can be directlyadopted, and the COD of the effluent is less than 100 mg/L.  The processflow adopted by this factory is shown in the figure.

Anaerobic-BiologicalFilter-Oxidation Pond Combination Treatment of Aldehyde-Containing AcidWastewater

Aldehyde-containingand acid-containing wastewater is produced in the production process of achemical plant. the wastewater cod is 6,000 mg/l and the pH value is 1.0. theplant adopts the combination treatment of anaerobic-biological filter-oxidationpond, and the effluent cod is less than 100 mg/l.  The process flowadopted is shown in fig. 4.