Mass balance assessment of triclosan removal during conventional sewage treatment

Jochen Heidler, Rolf U. Halden

Research output: Contribution to journalArticlepeer-review

272 Scopus citations

Abstract

The antimicrobial agent triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol; TCS) is a member of a larger group of polychlorinated binuclear aromatic compounds frequently associated with adverse environmental and human health effects. Whereas the structure and function of TCS would suggest significant resistance to biotransformation, biological wastewater treatment currently is considered the principal destructive mechanism limiting dispersal of and environmental contamination with this compound. We explored the persistence of TCS in a typical full-scale activated sludge US sewage treatment plant using a mass balance approach in conjunction with isotope dilution liquid chromatography electrospray ionization mass spectrometry (ID-LC-ESI-MS) for accurate quantification. Average influent and effluent concentrations (mean ± SD) of 4.7 ± 1.6 and 0.07 ± 0.06 μg l-1, respectively, revealed an apparent (liquid-phase) removal efficiency of 98 ± 1%. However, further analyses demonstrated that the particle-active TCS (80 ± 22% particle-associated in influent) was sequestered into wastewater residuals and accumulated in dewatered, digested sludge to concentrations of 30 000 ± 11 000 μg kg-1. Overall, 50 ± 19% (1640 ± 610 g d-1) of the disinfectant mass entering the plant (3240 ± 1860 g d-1) remained detectable in sludge, and less than half of the total mass (48 ± 19%) was biotransformed or lost to other mechanisms. Thus, conventional sewage treatment was demonstrated to be much less effective in destroying the antimicrobial than the aqueous-phase removal efficiency of the plant would make believe. Furthermore, study findings indicate that the common practice of sludge recycling in agriculture results in the transfer of substantial quantities of TCS to US soils used, in part, for animal husbandry and crop production.

Original languageEnglish (US)
Pages (from-to)362-369
Number of pages8
JournalChemosphere
Volume66
Issue number2
DOIs
StatePublished - Jan 2007
Externally publishedYes

Keywords

  • Antimicrobials
  • Biosolids
  • PPCPs
  • Sludge
  • Wastewater

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Chemistry(all)
  • Pollution
  • Health, Toxicology and Mutagenesis

Fingerprint Dive into the research topics of 'Mass balance assessment of triclosan removal during conventional sewage treatment'. Together they form a unique fingerprint.

Cite this