Keywords: 
• carbamazepine /
• ecological risk /
• wastewater reclamation /
• kinetic model /
• ozonation /
• chlorination

Abstract: Carbamazepine has become one of the most intensively studied pharmaceuticals due to its frequent occurrence in wastewater and the aquatic environment as well as its adverse impact on aquatic ecosystems. The Qinghe Wastewater Reclamation Plant (QWRP) in Beijing was investigated as a case study to characterize the removal of carbamazepine by the “ultrafiltration – ozonation – chlorination” process. A kinetic model was developed for the ozonation and chlorination processes, respectively, and model parameters were identified with the Hornberger-Spear-Young algorithm based on Latin Hypercube Sampling. The toxicity data of carbamazepine on the native aquatic species of Beijing were obtained from the ECOTOX database developed by the U.S. Environmental Protection Agency, and used to develop the species sensitivity distribution (SSD) models. The SSD models, together with the simulated carbamazepine concentration in the QWRP effluent, were finally applied to assess the expected total risk (ETR) of aquatic ecosystems which were augmented by the effluent. The ozonation and chlorination models could simulate the concentrations of carbamazepine, total organic carbon, and ammonia nitrogen quite well, with a relative error generally below 20%. All the sensitive model parameters could be well identified with their uncertainty significantly reduced. Among the 7 tested SSD models, log-normal distribution and log-logistic distribution models gave better performance in fitting the toxicity data of carbamazepine on the 6 native aquatic species of Beijing, and they estimated the ETR of aquatic ecosystems replenished by the QWRP effluent to be 7.4% and 8.5%, respectively.