Treatment of raw sewage in a temperate climate using a UASB reactor and the hanging sponge cubes process

Lalit K. Agrawal, Yasuhiro Ohashi, Etsuo Mochida, Hiroyuki Okui, Yasuko Ueki, Hideki Harada, Akiyoshi Ohashi

Research output: Contribution to journalConference article

75 Citations (Scopus)

Abstract

The treatability of raw sewage in a temperate climate (wintertime around 10-20°C) using an upflow anaerobic sludge blanket (UASB) reactor and the hanging sponge cubes process was evaluated. After being seeded with digested sewage sludge, a 47.1 L UASB reactor was continuously operated for more than 2 years by feeding raw sewage, which had average COD around 300 mg/L (41% soluble). During summertime at an HRT of 7 h, effluent COD approximately 70 mg/L total, 50 mg/L soluble and BOD5 20 mg/L total, 12 mg/L soluble was obtained. During wintertime also, treatment efficiency and process stability was good. With the hanging sponge cubes process using the effluent of the UASB reactor treating raw sewage, the following results were obtained. The ammonia oxidation rates of 1.9 and 3.5 g NH4-N·m-2·d-1 in a downflow hanging sponge cubes biofilter, under natural air intake only were obtained during wintertime and summertime, respectively. With post-denitrification and an external carbon source, 84% in average N(NO3 + NO2) was removed with an HRT of less than 1 hour and in the temperature range of 13 to 30°C using an upflow submerged hanging sponge bed bioreactor, under anaerobic conditions. The overall system using a UASB reactor and the hanging sponge cubes process could be quite an attractive treatment alternative.

Original languageEnglish
Pages (from-to)433-440
Number of pages8
JournalWater Science and Technology
Volume36
Issue number6-7
DOIs
Publication statusPublished - 1997 Dec 17
EventProceedings of the 1997 8th IAWQ International Conference on Anaerobic Digestion - Sendai, Jpn
Duration: 1997 May 251997 May 29

Keywords

  • Anaerobic treatment
  • Denitrification
  • Hanging sponge cubes process
  • Nitrification
  • Nitrogen removal
  • Post-treatment process
  • Raw sewage
  • Temperate climate
  • UASB reactor

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology

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