Pretreatment Of High Concentration Organic Chemical Wastewater By Digestion Combined Technology

Chemical, pharmaceutical, pesticide, dye, printing and dyeing andother enterprises produce a lot of high concentration organic wastewater.They are characteristic of high COD_Cr, low biodegradability, complexcomposition, containing a large number of toxic and hazardous substances.The wastewater if not treated and discharged directly into environment, itwill bring great environmental pollution. According to the requirements ofenvironmental protection department, the wastewater should be treatedwith incineration method by professional department, but the process coststoo much.We designed digestion combined technology: ferric-carbon microelectrolysis/ultrasonic-Fenton reagent-flocculation to pretreatment thehigh concentration organic chemical wastewater. This pretreatmenttechology can effectively reduce the concentration of COD_Crand TOC,improve biodegradability, change high concentrations of organic waste into ordinary organic wastewater. After further biochemical treatment, itcan be drainaged standard.The optimal conditions of the Micro-electrolysis/ultrasonic processwere: The volume ratio of iron to carbon was2:1, adjusted pH to4, thevolume ratio of solid to liquid was1:4, reaction number was2, eachreaction time was60min, frequency of ultrasonic was45KHz, Replacedthe iron-carbon filler after every processing; The optimum conditions ofFenton oxidation as follows: adjusted pH to4, volume ratio of H₂O₂towastewater was4%, reaction time was60min; The optimal reactionconditions of flocculation and sedimentation were: pH of initial waste was7⁸, dosage of PAC and PAM were300mg/L and5mg/L.The total removal rate of COD_Cr, TOC and p-nitrophenol reached90.25%,88.16%and85.53%through the treatment, The value of B/Cincreased from pre-treatment0.052to0.353, the biodegradability wasimproved remarkably. Ultraviolet spectrum had showed that the refractoryorganic pollutants were effectively degraded into small molecules. Thecombined processes pretreated two kinds of practical wastewater whichwere taken from the school chemical floor.After the treatment, the COD_Crdecreased from the beginning of11200mg/L,13800mg/L to1400mg/L,1210mg/L, the removal rate reached to87.5%and91.2%. In summary, the advanced oxidation combined process of highconcentration of organic waste pretreatment that this paper presents ischaracteristic of cost-effective, technical feasible, cost-effective, It hasvalue of promotion and application.