THE CITY COLLEGE OF NEW YORK
CHEMICAL ENGINEERING DEPARTMENT
Professor Lisa Axe
New Jersey Institute of Technology
Monday, April 23, 2018
Seminar will be held in MR-1307 (Marshak Building) at 2:00 PM
Reception will be held in Steinman Hall, Exhibit Room – 1st Floor
From 3:00 – 3:30 PM
Biologically Active Filters:
An Advanced Treatment Process for Contaminants of Emerging Concern
Recently, contaminants of emerging concern (CECs) have been reported throughout the water cycle, in wastewater treatment plant influents and effluents, surface water, and even in drinking water treatment and distribution systems. As they make their way into source water for drinking water treatment systems, CECs are an increasing concern for water utilities. In our study, we have focused on the hypothesis that we can convert existing filters and adsorbents from water treatment plants into biologically active filters (BAFs) as an advanced treatment process for CECs. The media being studied include granular activated carbon (GAC) and anthracite/sand dual media, which were collected from two treatment plants. In a bench-scale study, BAFs are being evaluated as a function of media, empty bed contact time (EBCT), and pre-ozonation. Their performance is monitored through studying DOC removal, UV254 reduction, and adenosine triphosphate (ATP) concentration as function of depth. For GAC BAFs, greater oxygen consumption, increased pH drop, and greater DOC removal normalized to ATP have been observed suggesting increased microbial activity as compared to dual-media BAFs. Sixteen CECs have been spiked in the source water. At an 18 min EBCT, GAC BAFs were highly effective with overall removals greater than 80% without pre-ozonation; exceptions included tri(2-chloroethyl) phosphate (TCEP) and iopromide. With a 10 min EBCT, the degree of CEC removal was reduced with less than half removed at greater than 80%. The dual-media BAFs showed limited removal with only four compounds removed greater than 80% (acetaminophen, ibuprofen, trimethoprim, and 17β-estradiol), and 10 compounds reduced by less than 50% with either EBCT. Pre-ozonation (3 mg/L) improved the removals through the BAF GAC and to a greater extent in dual media at both EBCTs. The microbial community is believed to play an important role in removal of natural organic matter and CECs. Next generation sequencing (Illumina MiSeq) is being used to characterize the microbial communities in the influent, effluent, and media. Proteobacteria has been observed to be most dominant bacteria in BAF influents and BAF media serving as a source for the latter. Planctomycetes phyla were dominant as well in both GAC and dual-media BAF. Based on a factorial analysis, media type is the most significant factor affecting the abundance of five bacterial phyla and 10 bacterial classes. EBCT impacted the abundance of the dominant bacteria phylum Proteobacteria at the phyla level, while the effect of pre-ozonation was observed to be significant at the class level for the two dominant bacteria, Proteobacteria and Planctomycetes. Current work includes isolating the CEC degraders, studying the kinetics of degradation, and modeling the BAF. The study demonstrates the potential and sustainability for using BAFs in treating CECs.
Lisa Axe is the Chair and a Professor in the Otto H. York Department of Chemical and Materials Engineering at NJIT. Dr. Axe’s research is in chemical and physical processes in environmental systems. Her group has been working with SUEZ North America on advancing biologically active filters in water treatment to address the plethora of emerging contaminants being detected in source water. Additionally, her group is studying reactive mineral coatings using core samples preserved for redox integrity. Much of her group’s efforts have been in understanding interfacial processes and their impact on water quality and contaminant mobility. Dr. Axe has been funded by Chemours, National Science Foundation, SUEZ North America, U.S. Army, NJ Department of Transportation, and NY State Department of Transportation. She was a recipient of the DuPont Young Professor Grant. She currently serves on the Chemours Science Advisory Board for the Chambers Works Site. Dr. Axe has published over 60 peer reviewed publications.