Removal of indigenous coliphages and fecal coliforms by a novel sewage treatment system consisting of UASB and DHS units

S. Uemura, K. Takahashi, A. Takaishi, A. Machdar, A. Ohashi, H. Harada

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)


A novel sewage treatment system, which consists of an upflow anaerobic sludge blanket (UASB) pre-treatment unit and the following downflow hanging sponge (DHS) unit for polishing up the UASB effluent, was developed as a cost-effective and easy-maintenance sewage treatment system for developing countries. A long-term experiment with actual was conducted in order to evaluate its treatment efficiency or organic substances, nutrients, and pathogen indicator microorganisms such as total coliphages, F+-specific RNA coliphages (RNA coliphages), and fecal coliforms. The main objective of this paper is to investigate the removal efficiency of those indicator microorganisms by the UASB-DHS combined system. The results obtained from the continuous flow experiment indicate a fairly promising removal of the indicator microorganisms, i.e., the log10 reductions of total coliphages, RNA coliphages, and fecal coliforms (based on sewage and DHS effluent) achieved were 2.01 log, 2.02 log, and 2.57 log, respectively. The UASB-DHS combined system was superior to the conventional activated sludge process in the reduction of fecal coliforms, but in the reductions of total and RNA coliphages, the system showed somewhat less removal efficiency. The vertical reducing patterns of the indicator microorganisms along the DHS reactor were also discussed.

Original languageEnglish
Pages (from-to)303-309
Number of pages7
JournalWater Science and Technology
Issue number11-12
Publication statusPublished - 2002


  • Coliphages
  • DHS
  • Developing countries
  • Fecal coliforms
  • Sewage treatment
  • UASB

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology


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