The Biodegradability of Trace Organic Contaminants During Wastewater Treatment

Authors:

  • W. O. Khunjar - Hazen and Sawyer
  • K. Chandran - Columbia University
  • V. Odize, K. Jones - Howard University
  • S. Murthy - DC Water
  • C. Bott, A. Keisel - Hampton Roads Sanitation District
  • L. Su, D. Aga - SUNY Buffalo

It is anticipated that trace organic compounds (TOrC) will emerge as an important determining factor in the selection and implementation of technologies used for the treatment of wastewater. To ensure effective treatment of these contaminants to below ecological no effect concentrations (NECs), multi-barrier approaches comprising both physico-chemical and biological treatment processes will be needed. Before we can design or operate systems to exploit biological TOrC removal, there is a need to accurately quantify the rate at which these reactions occur. At present, TOrC removal by activated sludge is documented to be highly variable. We hypothesize that this variability may partially be due to inconsistent experimental conditions employed by researchers assessing biodegradation. To improve our ability to describe and predict TOrC fate in biological systems, there is a need to develop a unified approach to guide research into this field.

In this paper, we present findings from our efforts to improve upon the existing standardized methodology for assessing TOrC biokinetics. Specifically, we evaluated how initial substrate conditions (TOrC or readily biodegradable substrates) impacted the estimated pseudo-first order kinetic parameters. As part of this work, we have developed a one year historical database of occurrence of five TOrCs (17alpha-ethinylestradiol (EE2) salicylic acid (SA), nonylphenol (NP), trimethoprim (TMP) and carbamazepine (d10-CBZ)) at three full-scale biological nutrient removal facilities. We are also currently deploying the optimized short-term batch tests to validate the test protocol and to estimate TOrC biotransformation rates at three full-scale facilities with varied degrees of biological nutrient removal capability.

For more information, please e-mail the author at wkhunjar@hazenandsawyer.com.

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