Water Resource Recovery Facilities (WRRFs) are essential for achieving the objectives of the Water Framework Directive but they also represent a significant source of three greenhouse gases (GHGs): carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Direct emissions come from the biological processes taking place within WRRFs while indirect emissions are associated with the energy produced outside the WRRF and imported to supply treatment units. Aeration of the biological tanks is known to be responsible for 50-60% of the total energy consumption on average and can reach up to 80% of the total energy demand in biological WRRFs, accounting for most of the indirect emissions of GHGs from these facilities. According to Eurostat data, wastewater treatment is still inadequate, especially in southeast European countries. Pollutant loads treated in aerobic plants in Europe are predicted to continuously increase in the coming years. This brings increasing energy requirements and the need for sustainable solutions for wastewater treatment. Therefore, the carbon footprint of WRRFs needs to be significantly reduced by optimizing treatment steps and lowering energy requirements.
LIFE LESSWATT aims to target both the environmental issues related to the energy consumption of WRRFs and their direct GHG emissions. The project will develop an innovative tool for assessing and minimizing both direct and indirect contributions of aerated compartments in WRRFs to the facility’s overall carbon footprint. This tool incorporates two innovative elements: the LESSDRONE, an automated, wireless and self-moving device for monitoring Oxygen Transfer Efficiency (OTE) and GHG emissions under normal operating conditions; and a model-based user-friendly tool (protocol) for converting complex information into concrete actions aimed at minimizing the carbon footprint. The tool’s effectiveness will be demonstrated and validated in the WRRFs of tannery CUOIODEPUR and in five other plants, three in Italy and two in the Netherlands.
The LIFE LESSDRONE tool will also facilitate the implementation of EU and national environmental policies by:
Effectively evaluating the impact of new climate-related environmental policies;
Making the implementation of environmental policies less costly;
Facilitating compliance with the European regulation establishing a European Pollutant Release and Transfer Register; and
Providing widely applicable guidelines for European WRRFs located in climatically similar regions, identifying the best equilibrium between OTE and GHG emissions.
The main outcome will be a tool for assessing and minimizing the overall GHG emissions due to aerobic biological wastewater treatment in the tannery plant of CUOIODEPUR with expected savings in energy for aeration in the range of 10-25%.
In the six pilot wastewater treatment plants where the protocol will be applied, it is expected to achieve:
Potential energy saving of about 9 800 000 kWh/y and 4 500 tCO2eq/y;
Increased aeration efficiency by 10-30%;
Reductions of 10-30% in indirect GHGs emissions due to aeration;
Improved reliability of GHGs emission inventories;
Considerable reduction of costs for water services; and
A business plan for the commercialization of the prototype and the protocol.