Removal of heavy metals and dewaterability of pure terephthalic acid sludge facilitated by bioleaching
生物沥浸对精对苯二甲酸化工污泥脱水性能的提高及其重金属脱除效果

Removal of heavy metals and dewaterability effect of pure terephthalic acid sludge during bioleaching were investigated through batch flask experiments.Results showed that the dewaterability of chemical sludge was improved after bioleaching.The optimum dosage of microbial nutritional substance was 5 g·L-1.Under this condition,the pH in the sludge system declined from 7.37 to 2.29,and the specific resistance to filtration (SRF) value decreased from 62.64×1012 m·kg-1 to 2.36×1012 m·kg-1 after 2 days of bioleaching.The waste bioleached sludge was collected and dewatered by chamber filter press after multi-batch experiments under the optimum operation conditions.It was found that the 24h sedimentation rate of sludge was improved from 2% to 33% after the third batch of bioleaching process.The moisture of dewatered sludge was reduced to 45.9% by chamber filter press,and the sludge volume reduced 91.1% compared with the control.The removal efficiency of Cu,Cd,Pb,Zn and Co in sludge cake were 95.15%,85.20%,42.11%,82.59% and 64.42%,respectively.At the same time,the removal rate of COD and NH3-N in filtrate was 42.82% and 74.98% after sludge dewatering.It is obvious that the bioleaching technology could not only improve the dewaterability of chemical industry sludge but also remove the heavy metals to some extent.This study has a significant implication for the bioleaching method application and promotion in the chemical industry field.