Comparison of contaminants of emerging concern removal, discharge, and water quality hazards among centralized and on-site wastewater treatment system effluents receiving common wastewater influent

• Published in: The Science of the total environment Vol. 466-467; pp. 976 - 984
• Main Authors: Du, Bowen, Price, Amy E., Scott, W. Casan, Kristofco, Lauren A., Ramirez, Alejandro J., Chambliss, C. Kevin, Yelderman, Joe C., Brooks, Bryan W.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2014
• Subjects: Animals; Chromatography, Liquid; Decentralized wastewater treatment; Effluent; Environmental Exposure; Environmental Monitoring; Fishes - metabolism; Pharmaceutical Preparations - analysis; Pharmaceutical Preparations - blood; Pharmaceuticals; Seasons; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry; Texas; Waste Disposal, Fluid; Wastewater indicators; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - blood; Water Quality; Texas; Wastewater indicators; Decentralized wastewater treatment; Effluent; Water quality; Pharmaceuticals
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2013.07.126

A comparative understanding of effluent quality of decentralized on-site wastewater treatment systems, particularly for contaminants of emerging concern (CECs), remains less understood than effluent quality from centralized municipal wastewater treatment plants. Using a novel experimental facility with common influent wastewater, effluent water quality from a decentralized advanced aerobic treatment system (ATS) and a typical septic treatment system (STS) coupled to a subsurface flow constructed wetland (WET) were compared to effluent from a centralized municipal treatment plant (MTP). The STS did not include soil treatment, which may represent a system not functioning properly. Occurrence and discharge of a range of CECs were examined using isotope dilution liquid chromatography–tandem mass spectrometry during fall and winter seasons. Conventional parameters, including total suspended solids, carbonaceous biochemical oxygen demand and nutrients were also evaluated from each treatment system. Water quality of these effluents was further examined using a therapeutic hazard modeling approach. Of 19 CECs targeted for study, the benzodiazepine pharmaceutical diazepam was the only CEC not detected in all wastewater influent and effluent samples over two sampling seasons. Diphenhydramine, codeine, diltiazem, atenolol, and diclofenac exhibited significant (p<0.05) seasonal differences in wastewater influent concentrations. Removal of CECs by these wastewater treatment systems was generally not influenced by season. However, significant differences (p<0.05) for a range of water quality indicators were observed among the various treatment technologies. For example, removal of most CECs by ATS was generally comparable to MTP. Lowest removal of most CECs was observed for STS; however, removal was improved when coupling the STS to a WET. Across the treatment systems examined, the majority of pharmaceuticals observed in on-site and municipal effluent discharges were predicted to potentially present therapeutic hazards to fish. •An analysis of effluents from wastewater systems receiving a common influent was performed.•Seasonal differences of select pharmaceuticals were identified in influent wastewater.•Removal of pharmaceuticals by an advanced aerobic onsite system compared to a centralized system•Various pharmaceuticals in effluents were predicted to present therapeutic hazards to fish.