Identification And Removal Of Particular Pollutants In Papermill Wastewaters By Adsorption-catalytic Ozonation

Organic compounds and calcium ion in regenerated papermaking wastewater were analyzed by HPLC, GC-MS, AAS and other methods. Based on these some particular pollutants were chosen, and their migration and transformation law in wastewater treatment process were investigated. Removal of Diisobutyl phthalate (DIBP) in papermaking wastewater by adsorption-catalytic ozonation was investigated, and the effect of operating parameters such as ozone dosage, granular activated carbon (GAC) dosage, pH value was studied. Furthermore, the effect of doping nitrogen of activated carbon on adsorption-catalytic ozonation was also examined under the optimum conditons.Results showed that regenerated papermaking wastewater contained a considerable amount of pollutants, and Diethyl phthalate (DEP), DIBP, dibutyl hydroxy toluene (BHT), Lignin and Ca²⁺ were chosen as particular pollutants for their refractory biodegradation and negative effect. Total COD_Cr percent of DEP, DIBP, BHT, Lignin in effluents increased gradually from 7.1% (primary clarifier) to 33.6% (IC reactor). Removal effect of DIBP by adsorption-catalytic ozonation was better than that by GAC adsorption or single ozonation, and removal rate of DIBP was enhanced by 9% and 20%, respectively. Increase of ozone inlet flux, GAC dosage, and pH was benefit for the removal of DIBP by adsorption-catalytic ozonation. Catalytic oxidation predominated in the removal of DIBP, and a kinetic model of adsorption-oxidation-regeneration for this process was established. Nitrogen doping of GAC could enhance the performance of adsorption-catalytic ozonation. When nitrogen doping of GAC was fulfilled by 8 wt.% ammonia soaking, the adorption effect of DIBP was enhanced by 10% and the removal effcet of DIBP was increased by 13% in adsorption-catalytic ozonation.