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Treatment Processes for Removal of Wastewater Contaminants (WERF Report INFR8SG09)
Citation:
Novak, J., P. Vikesland, AND A. Pruden. Treatment Processes for Removal of Wastewater Contaminants (WERF Report INFR8SG09). Water Environment Research Foundation, Alexandria, VA, 2012.
Impact/Purpose:
This report: • Demonstrates that the presence of colloidal material in the wastewater effluent was found to have a significant effect in the removal of blaTEM and vanA antibiotic resistance genes (ARG), which encode resistance to β-lactam and glycopeptide antibiotics, respectively. There was no significant impact of colloids on the removal of 16S rRNA genes, which are representative of total bacteria and background DNA. • Demonstrates that the removal of colloid-associated blaTEM and vanA ARGs from wastewater was primarily associated with the removal of colloids between 0.10μm and 100kDa in size. This size range is removed by activated sludge with nitrification/ denitrification. • Demonstrates that the majority of nonylphenol and the nonylphenol ethoxylate, NP2EO, were associated with the size fraction between 1.2μm and 100kDa so much of the removal could be accomplished by conventional primary and activated sludge treatment. However, some nonylphenols were associated with the size fraction passing a 1kDa ultrafiltration membrane, indicating that this fraction was soluble or associated with very small particles and advanced treatment would be needed to remove nonylphenols to very low concentrations. • Provides data for the removal of nonylphenols for two advanced wastewater treatment processes and shows the benefits of several advanced treatment processes including a membrane bioreactor, granular activated carbon and tertiary filtration.
Description:
This study investigated the nature of colloids associated with wastewater effluents. It also evaluated the association of emerging contaminants with these wastewater colloids. Two distinct emerging contaminants were investigated to gain general insight into the potential importance of emerging contaminant interactions with wastewater colloids. The first and major component of the study was to evaluate the association of antibiotic resistance genes (ARGs) with colloids and the removal of ARGs by membrane processes. This is designated in the report as Part I. The second aspect of the study was to obtain preliminary data on the potential association of nonylphenol with a range of colloidal size fractions and to evaluate their removal in wastewater treatment plants. This is designated Part II. Overall, the goal was to determine the degree of association of two representative emerging contaminants, ARGs and nonylphenols, with various colloidal sizes and to determine the removal efficiency of these colloids in wastewater treatment plants. If the emerging contaminants are associated with the larger size fractions, then more conventional treatment processes can be used. If emerging contaminants are associated with the smaller size fractions, advanced processes such as nanofiltration or activated carbon may be needed. [NOTE: The link below connects to a WERF site where the Final Report can be downloaded for free, after registering at the WERF site. For some projects the Executive Summary is available and can be downloaded for free without registering on the WERF site.]
