Application of QSARs Model in Toxicity Evaluation of Wastewater to Bio-treatment System in WWTP

The gaps of data for influent toxicity to biological system create the need for estimation methodologies to predict their hazardous impacts and screen the wastewater discharged into wastewater treatment plants. In this paper, 24 chemicals were chosen, and the method of their toxicity concentration expression for activated sludge system, defined as C_50%, were investigated based on sludge respiration rate for mid-term (24 hours) and short-term (30 minutes) respectively. QSARs models of mid-term and short-term toxicity on activated sludge were then developed from the physicochemical parameter of K_ow and molecular structure descriptor of E_lumo, and could describe the obtained data set well with high coefficient and small standard error. Compared with the QSARs model of short-term toxicity, the mid-term toxicity QSARs model were more stable and accurate. The obtained results confirmed that K_ow and E_lumo are crucial QSARs model descriptor for toxicity effect on activated sludge system.