EXAMINING GRANULAR ACTIVATED CARBON ADSORPTION OF ORGANIC CONTAMINANTS FROM WATER: ENDOCRINE DISRUPTORS / PHARMACEUTICALS, METHYL TERT-BUTYL ETHER, AND BENZENE

Open Access
- Author:
- REDDING, ADAM MICHAEL
- Graduate Program:
- Environmental Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 25, 2008
- Committee Members:
- Fred Scott Cannon, Committee Chair/Co-Chair
Brian Dempsey, Committee Member
John Michael Regan, Committee Member
Klaus Keller, Committee Member - Keywords:
- benzene
MTBE
endocrine disruptors
activated carbon - Abstract:
- Granular activated carbon (GAC) is a widely used and cost effective method for removing organic contaminants from drinking water. The work herein examines the use of GAC for removing three contaminants of interest: endocrine disruptors, pharmaceuticals, and personal care products (EDCs/PPCPs), methyl tert-butyl ether (MTBE), and benzene. Each of these contaminants occurs in drinking water sources between part-per-billion (ppb, μg/L) and part-per-trillion (ppt, ng/L) concentrations. With improved low detection limits at part-per-trillion (ppt) levels, endocrinedisrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) are now identifiable in many drinking waters. The examination herein assesses sorption of 29 EDCs and PPCPs at ppt concentrations using granular activated carbon GAC in rapid small-scale column tests (RSSCTs). Thereafter, to better understand the unique adsorption behavior of EDCs/PPCPs at ppt levels, a quantitative structure-activity relationship (QSAR) model was developed using the observed bed volumes to breakthrough, carbon properties, and a defined set of molecular properties and descriptors. As a relatively water-soluble gasoline additive, MTBE is found in many source waters. The removal of MTBE in RSSCTs was appraised and compared to GAC pore size and empty-bed contact time to determine the influences of these parameters. The performance of seven hydrophobic GACs at three small-scale empty-bed contact times was statistically compared to the pore volume distributions of the GACs. By controlling access to micropores, mesopore volume was shown to be the controlling factor in RSSCT iv capacity. Mass transfer rate was shown to increase with micropore volume and decrease with mesopore volume. Due to shipping of gasoline on the Ohio River, the Greater Cincinnati Water Works can be heavily impacted by spills, including relatively soluble benzene. The objective of the work herein was to determine the most effective regeneration protocol for benzene removal from the influent Cincinnati water. RSSCTs for benzene removal were performed using a virgin Filtrasorb 400 (F400) GAC, a GAC regenerated at the Greater Cincinnati Water Works (GCWW), three GACs regenerated at Penn State University (PSU), and three pilot-scale GACs produced at the GCWW. Spent GAC was acquired from the GCWW and regenerated at PSU via protocols varying the use of steam and treatment time in a thermogravimetric analyzer (TGA). These lab-scale regeneration protocols were then applied at the pilot-scale using a reactor at the GCWW. Pilot-scale regeneration produced a GAC with improved benzene removal as compared to the standard regenerated GAC.