STUDY OF FATE AND TRANSPORT OF EMERGENT CONTAMINANTS AT WASTE WATER TREATMENT PLANT

Abstract

Contaminants of emerging concern such as pharmaceuticals, personal care products, bacteria, viruses, and pesticides are frequently found in waste water, groundwater, and surface waters. The search to find the sources of these compounds has routinely led to wastewater treatment plants (WWTPs) as an entry point of contaminants into the natural environment. The unknown effects of low concentrations of emerging contaminants in the aquatic ecosystem require scientists to study the occurrence, sources, fate, and transport of these compounds in wastewater treatment, to better understand and possibly identify mitigation opportunities. Reducing the contaminant levels in WWTP effluent helps minimize the contamination in lakes and rivers, which are both WWTP receiving waters as well as drinking water sources. Emerging contaminants end up in wastewater through several pathways including the disposal and use of consumer products, farm runoff, toxic spills, and excretion via the urine and feces of those consuming pharmaceuticals. The human body only metabolizes a percentage of each drug taken, expelling the rest into the municipal wastewater system. Another source is from consumer products such as soap, shampoo, disinfectant washes, and toothpaste which contain biologically active compounds that, when used, release these contaminants into the sewer system where they are then transported to a wastewater treatment plant (WWTP). Municipal wastewater treatment plants are not specifically designed to deal with the trace levels of emerging contaminates found in wastewater and many compounds pass through conventional treatment systems without removal. From the WWTP effluent, emerging contaminants are discharged into surface waters where they may have measurable effects on aquatic life at low concentrations. Once in surface waters, pharmaceuticals have been shown to interrupt the natural biochemistry of many aquatic organisms including fish and algae. Many of the problems associated with the removal of emerging contaminants from municipal wastewater stem from their low concentrations and chemical diversity, which make detection and analysis difficult. Low concentrations require extremely sensitive analytical equipment while the wide range of distinct chemical compounds necessitates techniques to identify many chemicals at once. Only recently have scientists become aware of the presence of some emerging contaminants in wastewater because analytical techniques able to detect them at the ng/l have only recently been developed. As laboratory procedures are developed and emerging contaminants can be accurately quantified, scientists are becoming increasingly able investigate the sources, removal pathways, and fate of pharmaceuticals in municipal wastewater. In addition to emerging contaminants, the potential entrance of prions into the wastewater system and their fate in wastewater treatment is an area of concern and a topic of interest in this study. A sampling program will implement to monitor the sources and fate of emerging contaminants in municipal wastewater treatment system. Laboratories will test for twelve different classes of emerging contaminants ranging from pharmaceuticals to flame-retardants. Hospitals, funeral homes, slaughterhouses and residential neighborhoods will monitor to determine possible point sources of contaminants into municipal sewer systems. Multiple locations within each wastewater treatment plant will monitor to trace the fate of each emerging contaminant class through the wastewater treatment process in an attempt to understand the fate removal pathways of each contaminant.