Methods for measuring greenhouse gas emissions from sanitation and wastewater management systems

The report analyzes seven categories of enclosure-based and open measurement methods for greenhouse gas emissions in sanitation systems. It finds that while enclosure-based methods like flux chambers are widely used, they are limited by scale. Emerging optical and remote sensing methods offer broader coverage but are constrained by high costs. The document highlights a critical lack of empirical data for non-sewered sanitation in low- and middle-income countries and advocates for standardized, affordable methodologies and increased collaboration to improve national greenhouse gas inventories.

• Sanitation and wastewater management systems contribute over half a billion tonnes of CO2 equivalents annually, representing approximately 1.3% of global greenhouse gas emissions, though this may be an underestimate due to limited empirical data.
• Enclosure-based methods, specifically static and flow-through flux chambers, are the most common tools used across the sanitation chain, but they often require adaptation from agricultural designs to fit liquid-air interfaces and can underestimate total emissions in large facilities due to scale limitations.
• There is a complete absence of literature regarding the measurement of greenhouse gas emissions at the user interface (e.g., toilets and urinals), likely because the short residence time of excreta is assumed to result in negligible emissions.
• Open measurement methods, including optical sensors and remote sensing, provide high-resolution and broad-scale monitoring but are primarily utilized in high-income countries due to high equipment costs and the need for specialized expertise.
• The IPCC Guidelines for National Greenhouse Gas Inventories lack comprehensive emission factors for many non-sewered technologies, only including factors for pit latrines and septic tanks, which leads to significant uncertainties in emissions inventories.
• High costs of equipment and the requirement for highly qualified personnel in chemistry and atmospheric sciences create significant barriers to empirical measurement in low- and middle-income countries.
• A lack of standardized methodological approaches and equipment designs, combined with variability in sanitation technology construction (such as pit latrine depth), limits the comparability of results between different empirical studies.
• Interest in sanitation emissions data is driven by national reporting obligations, the search for low-emissions technology options, and the pursuit of climate finance through carbon credits.

APA

Ddiba, D., Rahmati-Abkenar, M., & Liera, C. (2024). Methods for measuring greenhouse gas emissions from sanitation and wastewater management systems. Stockholm Environment Institute. https://www.sei.org/wp-content/uploads/2024/07/methods-greenhouse-gas-emissions-sanitation-sei2024-030.pdf

Chicago

Ddiba, Daniel, Mahboubeh Rahmati-Abkenar, and Carla Liera. Methods for measuring greenhouse gas emissions from sanitation and wastewater management systems. Stockholm Environment Institute, 2024. https://www.sei.org/wp-content/uploads/2024/07/methods-greenhouse-gas-emissions-sanitation-sei2024-030.pdf.

Wikipedia

{{cite report |last1=Ddiba |first1=Daniel |last2=Rahmati-Abkenar |first2=Mahboubeh |last3=Liera |first3=Carla |title=Methods for measuring greenhouse gas emissions from sanitation and wastewater management systems |publisher=Stockholm Environment Institute |date=July 2024 |url=https://www.sei.org/wp-content/uploads/2024/07/methods-greenhouse-gas-emissions-sanitation-sei2024-030.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{ddiba2024methods, author = {Ddiba, Daniel and Rahmati-Abkenar, Mahboubeh and Liera, Carla}, title = {{Methods for measuring greenhouse gas emissions from sanitation and wastewater management systems}}, institution = {Stockholm Environment Institute}, year = {2024}, month = jul, url = {https://www.sei.org/wp-content/uploads/2024/07/methods-greenhouse-gas-emissions-sanitation-sei2024-030.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }