LASSO-3 continues the successful research series. Building on the previous projects LASSO and LASSO-2, long-term measurements of gaseous and dissolved nitrous oxide at the Schönerlinde wastewater treatment plant will be continued and expanded over a period of 18 months.

Nitrous oxide (N₂O) is one of the major greenhouse gases, along with carbon dioxide (CO₂) and methane (CH₄). In wastewater treatment plants, nitrous oxide may be produced during the treatment process and released into the atmosphere. There, it contributes to the depletion of the ozone layer and is about 300 times more harmful to the climate than carbon dioxide.

The underlying microbiological processes are generally well understood. However, it remains difficult to estimate actual nitrous oxide emissions for individual treatment plants and specific operating conditions. Representative long-term data that could explain the influence of various factors on N₂O formation are largely lacking to date.

In order to collect and analyze precisely this data and to verify the representativeness of previous measurements, LASSO-3 focuses on liquid and gas measurements at additional points in the activated sludge basin. In addition, variations in process parameters—such as dissolved oxygen levels—are specifically taken into account to better identify correlations in the formation process.

Based on this, appropriate measures will be developed on-site to reduce nitrous oxide emissions in the future and thereby actively contribute to climate protection.

KWB’s project tasks include, among other things:

•    overseeing the monitoring system over an 18-month period,

•    maintaining and calibrating the sensors, as well as

•    sampling, analyzing, and evaluating the collected data.

In addition, LASSO-3 continues to share insights on nitrous oxide measurements with other wastewater treatment plant operators, such as Hamburg Wasser and the Ruhrverband. The findings thus make an important contribution to reducing greenhouse gas emissions, both within the framework of Berliner Wasserbetriebe’s climate protection strategy in Berlin and far beyond.