Project

Measuring greenhouse gas emissions from on-site sanitation systems

Greenhouse gas (GHG) emissions from the sanitation sector, and particularly on-site sanitation systems, have been greatly underestimated globally due to poor measurement, monitoring and verification. This project seeks to contribute towards establishing reliable methods to estimate the GHG emissions from on-site sanitation systems and catalyse action within the sanitation sector to meet global climate targets as established under the Paris agreement.

Active project

2023–2024

Project contact

Daniel Ddiba / daniel.ddiba@sei.org

Black septic tank that is partially buried in the ground. The tank is leaking dirty polluted water into the ground next to it. Green algae is growing in the water. — Black septic tank partially buried and leaking dirty polluted water into the ground.

Photo: Willem Cronje/Getty

Background

Recent research found that GHG emissions from Kampala’s sanitation system which largely consists of on-site technologies, could be contributing around half of the city’s total emissions. The IPCC Guidelines for National Greenhouse Gas Inventories are presently the gold standard for measuring, monitoring, and reporting GHG emissions from various sectors, but they contain some fundamental limitations. For sanitation systems, the emission factors provided in the guidelines mainly focus on centralised wastewater treatment plants with pit latrines and septic tanks being the only included sanitation technologies. This neglects the multiple other sanitation technologies that are used by billions of people, especially in the global south.

Given the growing interest from major stakeholders such as the World Bank to consider sanitation emissions in citywide inclusive sanitation planning and investments in various country programs, as well as the urgency of climate action to meet the 1.5-degree target under the Paris Agreement, these limitations in measuring, monitoring, and reporting GHGs are a serious cause for concern.They are also an opportunity to highlight the poor sanitation conditions that the populations are exposed to.

The potentially significant GHG emissions from on-site sanitation systems imply that they should be a core part of countries and cities’ climate mitigation efforts. However, this requires more reliable methods for measuring, monitoring and verification (MMV) of GHG emissions from on-site sanitation systems. The available methods for MMV of GHG emissions either involve field or lab-based direct measurements or modelling-based approaches using Life Cycle Assessment (LCA) models and other software such as SEI’s Low Emissions Analysis Platform (LEAP) but they have historically focused on centralised wastewater treatment systems and mainly on conditions in the Global North.

Having methods that are applicable to on-site sanitation technologies and systems and for Global South conditions could catalyse more work on in-situ measuring, monitoring and verification of GHG emissions, which could also lead to more reliable data for model-based approaches as well as emission factors in guidelines such as those from the IPCC.

Limitation

There is lack of an overview of available methods for measuring, monitoring and verification of GHG emissions with guidance on how they can be adapted and applied to on-site sanitation systems. This information gap hinders effectively targeted climate mitigation interventions in sanitation systems by utilities, municipalities or cities and national governments in the Global South. It also creates a hurdle towards access to climate finance and carbon finance, which could have the double benefit of reducing emissions and improving sanitation systems for underserved communities.

Aims

The project aims are:

To review existing methods for measuring, monitoring and verification of GHG emissions with reference to their potential use for on-site sanitation systems in Global South conditions.
To create a guidance note for policymakers and practitioners on the methods available, their pros and cons and how to adapt and use them for on-site sanitation systems.
To identify gaps in the existing methods and potential ways to address them.

Outputs

Project activities include:

1) Scoping review: A scoping review will be conducted to identify existing methods for measuring, monitoring and verification of GHG emissions, and assess their pros and cons for potential use for on-site sanitation technologies and systems in Global South conditions. This will cover both direct and indirect measurement methods and model-based approaches.

2) Interviews: Semi-structured interviews with relevant stakeholders will be conducted to explore how the methods identified could be useful to them and the pros and cons they foresee based on their experience of conditions on the ground in their country. The stakeholders will include representatives from sanitation utilities, and relevant municipal authorities and government ministries.

3) Workshops and networking activities: We will conduct two consultative workshops to discuss preliminary findings from the review and interviews and obtain feedback and input to the work from relevant stakeholders. The workshops will involve stakeholders from the sanitation sector as well as the GHG measurement and climate change community and will be held in the Autumn of 2023.

Daniel Ddiba

Research Fellow

SEI Headquarters

Mahboubeh Rahmati Abkenar

Jaee Nikam

Ngongang Wandji Danube

Research Fellow

SEI Africa

Brenda Ochola

Communications and Impact Officer

Communications

SEI Headquarters

Funding

Funding for this research is provided by the Swedish International Development Cooperation Agency (Sida), through core support to the Stockholm Environment Institute.