Mitigating N2O to tackle your GHG emissions

N2O impact is 35 times higher than expected - this is what you need to know.

Climate change is mainly due to human activities which have released huge amounts of greenhouse gases (GHGs) since the industrial revolution.

N2O (also called Laughing Gas) is a strong greenhouse gas with a global warming potential (GWP) over 100 years 265 times higher than an equivalent mass of CO2.

The Intergovernmental Panel on Climate Change (IPCC) publishes guidelines for national GHG emission inventories. In the AR6 (2019 version) they reviewed the N2O Emission Factor (EF) to a 40 times higher value : 1.6% kg N-N2O /kg N.

Since then, various studies have shown that N2O could be responsible for up to 60% of the overall GHGs of WWTP process.

Controlling and monitoring N2O production pathways, although theoretically possible, is not easily achieved. Indeed, it is important to understand that variable operating conditions and process types are going to influence the formation of N2O. In addition, there is still an ongoing technical debate regarding the specific contribution of different N2O production pathways. (Vasilaki et al. 2019 - Duan et al. 2021

First, we need to know a couple of things about you

A national challenge

The Netherlands have agreed to a strategic vision on the "Objective Net Zero" dynamic and the Dutch government has been proactively addressing this concern by implementing various initiatives. For instance, the government has set strict emission limits for N2O in wastewater treatment plants, aiming to reduce its impact on climate change, from 0.6 to 0.2 megatons by 2030. Additionally, they have promoted the use of advanced treatment technologies that are more efficient in minimizing N2O emissions and support facilities to implement these technologies. This involves an investment of €12 million in subsidies to the water boards to make sewage treatment process more sustainable, €8.6 million being dedicated to laughing gas reduction. The Dutch government has also invested in research and development projects to explore innovative solutions for reducing N2O in waste water treatment processes.

On a larger scope, the government has taken several initiatives to reach the objective of achieving net-zero emissions (reducing by 49% their emissions by 2030 and by 95% by 2050 compared to 1990 levels)

That said, it is still a big question mark for WWTPs to know how to get there? Indeed, lot's of studies have shown that the mitigation of N2O is very complex with many factors in place (plant design, location, size etc.). Therefore, where should WWTPs start ? What are the priorities to be compliant to The Netherlands regulations in 2025 (and many other European countries in the near future) ?

An increasingly political and regulatory topic

The issue of N2O in the wastewater treatment industry has gained considerable political and regulatory focus in recent years. The European Union (EU), in particular, has taken significant initiatives to address this concern. In the last proposal for the future UWWTP directive they now indicates that the industry needs to make additional effort to reduce green house gases

"Additional efforts are needed in the wastewater sector to: reduce its GHG emissions (34,45 million tonnes CO2e/year - around 0,86% of the total EU emissions)"

The EU's efforts reflect the growing recognition of N2O as a potent greenhouse gas and its potential impact on climate change. Starting in 2025, it will be mandatory for companies to work on a report with actual figures on their corporate sustainable responsability to measure their impact.

The risks related to climate change are becoming increasingly complex and more difficult to manage. The water sector is responsible for 3% of green house gases emissions. However, it is one of the few sectors in which we can act on scope 1, 2 and 3, due to the broad range of activities in the industry.

Once again, the question that remains is what is the role of WWTPs in this situation, and how can they play their part knowing that urban wastewater is one of the main sources of water pollution ?

Veolia, a partner that you can trust

In June 2023, The Danish Environmental Protection Agency selected Veolia to prepare proposals for regulation methods of N2O for the Danish WWTPs. The assignment contains several elements, out of which concrete measurement and calculation methods with the aim of establishing a validated measurement method.

In addition, also in 2023, Veolia - and its Hubgrade Performance Technology - has been appointed by the VUDP (Danish water company association) to be the selected partner to achieve a reduction in nitrous oxide emissions. Strong of many years of achievements in knowledge about N2O in treatment plants, the objective now will be to focus on full-scale demonstration and operational documentation of N2O mitigation for 8 WWTP.

Finally in 2023 Veolia has signed new contract in Europe and in the Netherlands to directly help WWTP mitigate their N2O.

If the Danish government, the Danish water board association and Dutch utilities are trusting Veolia and its Digital Twin Hubgrade Performance to understand, measure and mitigate N2O emissions, why not you?