Screening for Particular Pollutants in Regenerated Papermaking Wastewater and Study of Their Migration and Transformation

Organic compounds and calcium ion concentrations in regenerated papermaking wastewater were analyzed by HPLC,GC-MS,AAS and other methods.Based on the above results,some particular pollutants were chosen,and their migration and transformation characteristics in wastewater treatment process were investigated.Results showed that regenerated papermaking wastewater contained a considerable amount of pollutants,and DEP,DIBP,BHT,lignin and Ca~(2+)were chosen as particular pollutants for their refractory biodegradation and negative effect.Total COD_(Cr) percent of DEP,DIBP,BHT,and lignin in effluents increased gradually from 7.1%(primary clarifier) to 33.6%(secondary clarifier).A portion of DIBP,BHT and Ca~(2+)could be removed mainly through anaerobic IC process,and AO unit played an important role in the removal of DEP and lignin.It was easy for Ca~(2+) to accumulate in the effluents because of the high reusing rate of wastewater,which could result in granular sludge escaping from the IC reactor and affecting the whole wastewater treatment system.