Advanced Treatment of Pulp and Paper Mill Effluents by Activated Carbon Catalytic Ozonation

The ozonation of the pulp mill wastewater was carried out in the presence of activated carbon.Effect of ozonation process on CODCr and color removal rate at different original pH value,activated carbon inputs and reuses,improvement of biodegradability of the wastewater after activated carbon catalytic ozonation process were investigated.The results showed that CODCr and color removal rate were up to 40.2% and 91.6% respectively at 7.98 pH value,1g activated carbon dosage and 12 min ozonation reaction time,which was increased by 7.6% and 7.0% compared with that of single ozonation process,and the BOD5/CODCr ratio was also increased from 0.14 to 0.26,showing the biodegradability was improved obviously.Using recycled twice activated carbon for 12 min ozonation,CODCr removal rate was 35.4%,which was efficient.The infrared spectra of the activated carbon indicated that,during the process of ozonation,there were a large number of organic degradation products adsorbed on the activated carbon surface.