Assimilable organic carbon (AOC) and biodegradable dissolved organic carbon (BDOC): Complementary measurements

Isabel C. Escobar, Andrew A. Randall

Research output: Contribution to journalArticlepeer-review

143 Scopus citations


The objective of this study was to evaluate the necessity of measuring both assimilable organic carbon (AOC) and biodegradable dissolved organic carbon (BDOC) as indicators of bacterial regrowth potential. AOC and BDOC have often been measured separately as indicators of bacterial regrowth, or together as indicators of bacterial regrowth and disinfection by-product formation potential, respectively. However, this study proposes that both AOC and BDOC should be used as complementary measurements of bacterial regrowth potential. In monitoring of full-scale membrane filtration, it was determined that nanofiltration (NF) removed over 90% of the BDOC while allowing the majority of the AOC through. Heterotrophic plate counts (HPC) remained low during the entire period of monitoring due to high additions of disinfectant residual. In a two-year monitoring of a water treatment plant that switched its treatment process from chlorination to chlorination and ozonation, it was observed that the plant effluent AOC increased by 127% while BDOC increased by 49% after the introduction of ozone. Even though AOC is a fraction of BDOC, measuring only one of these parameters can potentially under- or over-estimate the bacterial regrowth potential of the water.

Original languageEnglish
Pages (from-to)4444-4454
Number of pages11
JournalWater Research
Issue number18
StatePublished - 2001

Bibliographical note

Funding Information:
The authors would like to extend sincere appreciation to Mark LeChevallier, Cheryl Norton, Issam Najm, Lina Boulos, Laurent Kiene and Carlos Campos (AWWARF RFP # 361 project team); James Taylor (University of Central Florida); Eugenia Carey and Jaya Navani (Palm Beach County Water Utilities District); Richard Dunham, Rick Coleman, Cliff Russell and Mike Malone (Orlando Utilities Commission); Christian Volk for invaluable technical support; and Tom Stocker (Koch Membranes/Fluid Systems) for providing the membrane samples. Additionally, the AWWARF RFP # 361 and EPA STAR fellowship program are thanked for providing financial support.


  • Assimilable organic carbon (AOC)
  • Biodegradable dissolved organic carbon (BDOC)
  • Biostability
  • Membrane filtration

ASJC Scopus subject areas

  • Water Science and Technology
  • Ecological Modeling
  • Pollution
  • Waste Management and Disposal
  • Environmental Engineering
  • Civil and Structural Engineering


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