Minimising CH4 emissions is essential for the wastewater industry to achieve GHG neutral wastewater management. There is currently a global effort to understand, quantify and mitigate CH4 production during wastewater treatment. In contrast, there has been very little work done towards the understanding of CH4 emissions from wastewater collection systems (sewers). The aim of this project is to measure and understand methane emission from sewers. In particular, online sensors suitable for sewer gas and dissolved methane measurement were evaluated and developed, and then further applied in actual sewers to capture dynamic methane data, in order to better understand and quantify methane production and emission from sewers. Also, the nature, extent and control of methane production in sewer sediments were comprehensively investigated.


  • Allconnex Water
  • Melbourne Water
  • DC Water is Life
  • Water Corporation
  • Unity Water

Project Outcomes

In this project, we measured, for the first time, significant dissolved and gaseous methane concentrations in sewers by using online sensors, enabling better understanding and management of methane emissions in sewer networks. The data clearly demonstrated that sewers are a significant source of methane and CH4 is produced from sewers in significant quantities. Also, sewer methane production and emission display significant temporal and spatial variation, indicating that online measurement will be the most suitable method for quantification.



  • Liu, Y.; Ni, B.-J.; Sharma, K. R.; Yuan, Z., 2015. Methane emission from sewers. Science of the total environment. 2015, 524-525, 40-51.
  • Liu, Y.; Sharma, K. R.; Fluggen, M.; O’Halloran, K.; Murthy, S.; Yuan, Z., Online dissolved methane and total dissolved sulfide measurement in sewers. Water Research. 2015, 68(1), 109-118.
  • Liu, Y.; Ni, B.-J.; Ganigue, R.; Werner, U.; Sharma, K. R.; Yuan, Z., 2015. Sulfide and methane production in sewer sediments. Water Research. 2015, 70(1), 350-359.
  • Liu, Y.; Sharma, K. R.; Ni, B.-J.; Fan, L.; Murthy, S.; Tyson, G.; Yuan, Z., 2015. Effect of nitrate dosing on sulfidogenic and methanogenic activities in sewer sediments. Water Research. 2015, 74, 155-165.
  • Liu, Y.; Sharma, K. R.; Murthy, S.; Johnson, I.; Evans, T.; Yuan, Z., 2014. On-line monitoring of methane in sewer air. Scientific Reports. 2014, 4, 6637.

Conference proceedings

  • Sharma, K. R.; Liu, Y.; O'Halloran, K.; Yuan, Z., 2015. Modelling of methane production in sewers. IWA Symposium on Systems Analysis and Integrated Assessment Watermatex 2015, Gold Coast, Australia.

Project members

Other members

  • Dr Yiwen Liu
  • Dr Bing-Jie Ni