Study On The Process Design Of Formaldehyde Wastewater Treatment

High concentration formaldehyde wastewater is the typical organicone which is difficult to degraduate and poisonous. The formaldehyde canreact directly with protein, DNA and RNA contained in germ, resulting ininhibiting biological activity, even causing death of germ. The generalbiochemical treatment can hardly meet the need of practical operation.Therefore, moderate pre-treatment with Fenton oxidation process onwastewater to satisfy the conditions of biochemical treatment can be adetailed and accurate reference for wastewater treatment in practice.This paper, by investigation on enterprises of phenol-formaldehyderesin production, and analysis on wastewater characteristics of resinproduction, puts forward the technique of Fenton oxidation process andSBR biochemical treatment. After testing, and comparing the treatmentresults of different processes and reaction conditions, we can find fromthe experiment that under the condition of COD_cr≤2500mg/L，BOD₅≤600mg/L，c（HCHO）≤200mg/L, the water output after treatmentcan reach the Grade III of comprehensive discharge standard of sewage（GB8978-1996）.The best HRT combination is0.5-hour oxidation process and6-hour biochemical reaction, which can totally remove theadverse effects brought by formaldehyde to biochemical treatment. Thispaper studies reaction kinetics during the course of treatment, and in theend, according to the testing results and practical engineering, it takes asan example a factory producing phenol-formaldehyde resin, and designs aset of treatment technique on basis of clean production. The direct cost ofwastewater treatment is9.25RMB/m³.