The Use of Water Quality and Process Models for Minimising Wastewater Utility Greenhouse Gas Footprints

The special session is organised by the IWA Task Group on Greenhouse Gases

When: Sunday June 19, afternoon (13.30-17.00)

Where: San Sebastian (TECNUN). Room 1.

Registration: required by email ( , entrance free


Although regulations in some countries are prompting water utilities to reduce their greenhouse gas (GHG) footprints, the water sector, as a whole, is voluntarily moving in the direction of a holistic approach to water management, and finding innovative ways to lessen its impact on climate change, while still meeting water quality goals.  The wastewater processes leading to GHG emissions in sewers and treatment plants are complex, as is their interrelation.  In order to efficiently evaluate the effects of specific GHG mitigation strategies on the overall  GHG footprint (i.e. collection, treatment, receiving water environment), and find a sustainable balance between energy, operational costs, greenhouse gas emissions, and water quality, an integrated mathematical modelling approach is required. The focus of the IWA Task Group on GHG is to develop modelling tools to help utilities find this balance.

The purpose of this workshop is to disseminate current knowledge on wastewater GHG emissions and model development gathered by the Task Group , as well as to discuss the consensus-driven approach the Task Group is taking to develop methane (CH4) sewer models and nitrous oxide (N2O) plant models, and implement them in a system-wide modelling framework so that the overall GHG footprint can be adequately assessed and minimised.  Furthermore, feedback on the approaches is welcomed from the participants.

Specifically, mechanisms and models of N2O emissions from biological wastewater treatment will be discussed, as well as plans to parameterise, calibrate, and validate these models within Activated Sludge Model (ASM) platforms.  Similarly, mechanisms and models of CH4 emissions from WWTPs and sewers will be discussed, as well as plans to develop, parameterise, calibrate, and validate these models within plant and sewer modelling platforms.  Tools for benchmarking and integrated modelling will also be discussed and cases demonstrated for the development and assessment of system-wide mitigation strategies.  The last area of the Task Group’s focus which will be discussed is gaps identification. This is critical for guiding new research to help achieve the Task Groups objectives.

Discussions anticipated during and at the end of the workshop include:

  • When to use and not to use models, as well as when to use and not to use simplified models
  • Nitrification and denitirifcation N2O mechanisms and models
  • CH4 measurements in sewers for model development
  • Synergies with ongoing research efforts

Who Should Attend

The workshop is intended for plant and sewer operations management, process and design engineers, and academics wishing to apply models for minimising GHG footprints.  Professionals attending will most likely be specialists in the areas of nutrient removal, water quality and process modelling, sewer systems, and ICA.  However, the workshop would also be beneficial to the non-specialist wanting to learn more on how modelling tools can be applied for sustainable water management practices.

Learning Objectives

Attendees will gain an understanding of the fundamentals behind biological wastewater treatment N2O emissions and sewer CH4 emissions; treatment process conditions leading to high, medium, and low risk of GHG emissions; and various applications and approaches in which models can be used for minimising GHG footprints.

Workshop Organisers/Speakers

Jose Porro Malcolm Pirnie Inc. USA TG Chair
Ingmar Nopens BIOMATH – UGent Belgium TG Co-chair/Subgroup Benchmarking Benchmarking
Kartik Chandran Columbia University USA Subgroup N-GHG
Marlies Kampschreur Waterboard Aa & Maas Maas Netherlands Subgroup N-GHG
Zhiguo Yuan AWMC Australia Subgroup CH4-GHG
Jing Liu Bioprocess Control Sweden Subgroup CH4-GHG
Andy Shaw Black & Veatch USA Subgroup Benchmarking
Sudhir Murthy DC Water USA Subgroup validation
Bernhard Wett ARA Consulting Austria Subgroup validation
Gustaf Olsson Lund University Sweden Discussion Moderator


Time Topic
13.30-14.00 Welcome address
Objectives of the TG
14.00-14.30 Subgroup N-ghg pathways and models
Status and future plans
14.30-15.00 Subgroup CH4-ghg pathways and models
Status and future plans
15.00-15.30 Coffee break
15.30-16.00 Subgroup Benchmarking and integrated assessment; Status and future plans
16.00-16.15 Gap identification / model validation; Status
16.15-17.00 Discussion

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