REMOVAL OF PHARMACEUTICAL CONTAMINANTS IN WATER

摘要

Pharmaceutical contaminants in drinking water could potentially lead to increasing risks of heart attacks, organ damage, mental health and even cancer. Because their presence, frequency of occurrence, or source may not be known, the chemicals being discovered in water that previously had not been detected or are being detected at levels that may be significantly different than expected. Removal of emerging contaminants is considered recently to be one of the most important processes within advanced Waste Water Treatment Plants (WWTPs) system. EPA is working to improve its understanding of a number of emerging contaminants, particularly Pharmaceuticals and personal care products (PPCPs). The objectives of this research are: 1) to identify the presence of selected emerging contaminants (Acetaminophen, Bezafibrate, Caffeine, Carbamazepine, Cotinine, Diclofenac, Gemfibrozil, Ibuprofen, Metoprolol, Naproxen, Sulfadimethoxine, Sulfamethazine, Sulfamethoxazole, Sulfathiazole, Triclosan and Trimethoprim). These contaminants were selected based on analyte selection criteria such as occurrence and availability of analytical standards, chronological ecotoxicity and environment relevance concentration, volume of use, and priority ranking, as well as literature survey on environmental occurrence studies in local WWTPs; 2) to estimate the corresponding WWTPs' removal efficiency; and the third objective is to evaluate the feasibility of applying ultra-filtration (UF) membrane combined with pre-treatments - powder activated carbon (PAC), coagulation, and sand filtration to remove the above emerging contaminants. This paper appraises the efficacy of ultra-filtration membrane coupled pretreatments to mitigate the presence of pharmaceutical contaminants in water. This work is a sequel to an earlier work, Liu et al., published in 2014 ASME-IMECE conference proceedings. In this study, water samples were analyzed using direct aqueous injection High Performance Liquid Chromatography with Tandem Quadrupole Mass Spectrometric (LC/MS/MS) detection. Through the project research period, both historical concentrations from WWTPs and experimental removal efficiency data were obtained. Results showed that conventional WWTP failed to remove Carbamazepine, Diclofenac and Trimethoprim, and in some cases, the concentration of these contaminants at the effluent were higher than influent concentration. Secondly, the ultrafiltration membrane system by itself was insufficient to remove the selected contaminants. However, the use of PAC as a pretreatment to the UF system was effective in removing most of the contaminants, and the removal efficiency was a function of PAC dosage. Results indicated that there is an optimum dosage where the removal efficiency must be balanced with the cost of PAC. Unlike PAC, coagulation coupled with filtration process, was not able to increase the contaminants removal efficiency significantly. Additionally, the historical data indicated there was no dramatic fluctuation of the target contaminants level during the 12-month monitoring period.