| Summary: |
Siloxanes are a growing concern for our environment and have a particularly important presence and effect in WWTPs. The domestic and industrial effluents carry a significant load of these widely used chemicals into these facilities, promoting an extended partition between the water line, the sludge line, and the surrounding air. Being predominantly lipophilic and volatile, siloxanes tend to prefer the latter two matrices, creating a false assumption that the conventional treatments are efficient in their removal, as the treated effluent concentrations are usually low. In fact, they hide in sludge and disperse in the air, creating other problems that urge for effective solutions. While the release into the atmosphere affects firstly the workers of the WWTPs and then the neighboring and even more remote areas due to the transport of the air masses, the preferential presence in the sludge can affect not only the quality of the composting products used as a soil additive in several crops but especially the efficiency of the biogas production units, essential for the economic and energetic sustainability of WWTPs.
These evidences demand a comprehensive assessment of the siloxanes cycle and behaviour in these facilities and effective actions to reduce the negative impacts. LaNSiloT's mission relies on a four-stage strategy, focusing on eight volatile methyl siloxanes (VMSs), the most commonly used in the industry and numerous consumer products and, consequently, found in WWTPs. First, a thorough mass balance to the presence of VMSs in a WWTP, which will also look for daily, weekly and seasonal patterns. Then, an assessment of relevant toxicological aspects including the estimation of the exposure of the WWTP workers and the surrounding population to the inhalation of VMSs, complemented with toxicological tests in pulmonary cells in standard VMSs and field samples. The third step is the development and on-site implementation of a technology to reduce and degrade  |
Summary
Siloxanes are a growing concern for our environment and have a particularly important presence and effect in WWTPs. The domestic and industrial effluents carry a significant load of these widely used chemicals into these facilities, promoting an extended partition between the water line, the sludge line, and the surrounding air. Being predominantly lipophilic and volatile, siloxanes tend to prefer the latter two matrices, creating a false assumption that the conventional treatments are efficient in their removal, as the treated effluent concentrations are usually low. In fact, they hide in sludge and disperse in the air, creating other problems that urge for effective solutions. While the release into the atmosphere affects firstly the workers of the WWTPs and then the neighboring and even more remote areas due to the transport of the air masses, the preferential presence in the sludge can affect not only the quality of the composting products used as a soil additive in several crops but especially the efficiency of the biogas production units, essential for the economic and energetic sustainability of WWTPs.
These evidences demand a comprehensive assessment of the siloxanes cycle and behaviour in these facilities and effective actions to reduce the negative impacts. LaNSiloT's mission relies on a four-stage strategy, focusing on eight volatile methyl siloxanes (VMSs), the most commonly used in the industry and numerous consumer products and, consequently, found in WWTPs. First, a thorough mass balance to the presence of VMSs in a WWTP, which will also look for daily, weekly and seasonal patterns. Then, an assessment of relevant toxicological aspects including the estimation of the exposure of the WWTP workers and the surrounding population to the inhalation of VMSs, complemented with toxicological tests in pulmonary cells in standard VMSs and field samples. The third step is the development and on-site implementation of a technology to reduce and degrade VMSs from the sludge just before the anaerobic formation of biogas, aiming to enhance the efficiency of the process while improving the quality of the biocombustible and reducing its hazardous footprint. Finally, a life cycle assessment (LCA) will close the circle and establish the environmental gains of this innovative approach, reinforced by a complete cost-benefit study.
LaNSiloT faces an ambitious endeavor - the reduction of no less than 50% of the siloxanes load from the biogas-producing sludge, but the reward will be even greater: completing with the utmost success a project developed by a highly skilled team and supporting companies that has a practical application towards the enforcement of a sustainable life and circular economy in a well-defined and concerning issue, being not only aligned with the national vision, but also embodying the spirit of the Societal Challenges of H2020. |