Influence of relaxation modes on membrane fouling in submerged membrane bioreactor for domestic wastewater treatment

Rasikh Habib, Muhammad Bilal Asif, Sidra Iftekhar, Zahiruddin Khan, Khum Gurung, Varsha Srivastava, Mika Sillanpää

Research output: Contribution to journalArticlepeer-review

65 Citations (Scopus)


Relaxation and backwashing have become an integral part of membrane bioreactor (MBR) operations for fouling control. This study was carried out on real municipal wastewater to evaluate the influence of different operational strategies on membrane fouling at equivalent water yield. Four relaxation modes (MBR10+0, MBR10+1, MBR10+1.5 and MBR10+2) were tested to analyze membrane fouling behavior. For the optimization of relaxation modes, fouling rate in terms of trans-membrane pressure, hydraulic resistances and characteristics of fouling fractions were analyzed. It has been observed that cake layer resistance was minimum in MBR10+1.5 but pore blockage resistance was increased in all relaxation modes. Moreover, high instantaneous flux contributed significantly to fouling rate at the initial stage of MBR operations. Relaxation modes were also efficient in removing irreversible fouling to some extent. Under all relaxation modes, COD removal efficiency ranged from 92 to 96.5%. Ammonium and TP removal were on the lower side due to the short solids and hydraulic retention time.

Original languageEnglish
Pages (from-to)19-25
Number of pages7
Publication statusPublished - 2017
Externally publishedYes


  • Fouling resistances
  • Membrane fouling rate
  • Relaxation modes
  • Soluble microbial products
  • Submerged membrane bioreactor

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Pollution
  • General Chemistry
  • Health, Toxicology and Mutagenesis
  • Environmental Engineering
  • Environmental Chemistry


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