Characteristics of soluble microbial products in effluent of a petrochemical wastewater treatment plant
石化综合污水处理厂出水溶解性微生物产物的特性

Soluble microbial products (SMP) are the mean compositions of residual COD in the effluents of biological wastewater treatment plant. In this study, ultrafiltration membranes with molecular weight cut off and XAD-8 resin were employed to identify the characteristics of the molecular weight distribution and hydrophobic/hydrophilic of SMP in the effluent of a typical petrochemical wastewater treatment plant. The results showed that the proportion of SMP in the residual COD was about 85% and the dominant composition of SMP was protein. Most of the organic matters of SMP have molecular weight lower than 1 kDa. The resin separating experiments showed that hydrophilic substance (HIS) and hydrophobic acids (HOA) were the main fractions of SMP in the effluent, accounting for 50% and 20% of the total SMP, respectively. HIS and HOA were the main substances need further removal.