Wastewater treatment for ships experiencing large temperature changes: the activated sludge/membrane-biofilm reactor

Yuhang Cai, Yi Hao Luo, Xiangxing Long, Asad A. Zaidi, Yue Shi, Dandan Zhou, Bruce E. Rittmann

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


A particular challenge to treatment systems for ship wastewater comes from low and variable temperatures. We evaluated the temperature response (35–15 °C) of a novel biological treatment system involving activated sludge followed by a membrane-biofilm reactor: the activated sludge/membrane-biofilm reactor (AS-ABfMemR). In this study, a pilot-scale AS-ABfMemR achieved over 96% chemical oxygen demand (COD) and 94% total nitrogen (TN) removal from a ship wastewater (550–960 mgCOD·L−1 and 52–77 mgTN·L−1) with a continuous operation with a hydraulic retention time of 12 h at 25 °C. The effluent COD and TN concentrations met IMO discharge standards at temperatures as low as 17 °C, which reduced the energy consumption for wastewater heating. The COD and TN removals of the biofilm stage became important (up to 34% and 35%, respectively) at low temperatures, and this compensated for the deterioration in performance of the aerobic sludge. The genus Azospira dominated in the biofilm's denitrification removal for TN at low temperature. In addition, the buildup of trans-membrane pressure was so slow that backwashing was not needed over the 90 days of continuous operation. These conclusions indicate that the pilot-scale AS-ABfMemR technology is an effective way for real ship sewage treatment under temperature variations.

Original languageEnglish (US)
Article number135852
StatePublished - Nov 2022


  • Activated sludge
  • Energy consumption
  • Membrane biofilm
  • Ship wastewater
  • Temperature

ASJC Scopus subject areas

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


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