Life cycle assessment of greywater treatment systems for water-reuse management in rural areas

Abstract

Water scarcity is a major concern worldwide. Population growth, as well as the intensive use of water resources for industrial and agricultural activities, among others, have caused water stress in various regions of the world. Rural areas are usually more affected due to water scarcity and a lack of sanitary infrastructure. The current practices associated with urban water management have been considered inefficient to respond to these problems. In recent years, the reuse of greywater has emerged as a promising and sustainable alternative. Several pilot greywater treatment systems have been implemented in rural areas of different countries, however, studies about the environmental impacts of these decentralized systems under different scenarios are lacking. In this work, the life cycle assessment of greywater treatment systems considering several scenarios was studied. Our results showed that the decrease in environmental impacts due to the saving of drinking water is more evident when the water supply is carried out through cistern trucks. This occurs because the environmental impact of land transport of water is extremely high and represents over 89% of the global warming indicator [kg CO2 eq] and 96% ozone depletion [kg CFC-11 eq] contributions of the system. Greywater treatment systems with backwashing and solar panels as a source of energy have lower environmental impacts, reducing CO2 and CFC emissions by 50% for the maintenance phase and by 85% (CO2) and 47% (CFC) for the operation phase. Furthermore, the acquisition of solar panels was economically feasible, with a payback of 19.7 years. This analysis showed the environmental feasibility of small-scale greywater treatment systems in rural areas affected by water scarcity. Furthermore, the proposed approach has contributed to understand the impact of greywater treatment systems in rural areas, which could become a support tool to integrate greywater reuse practices in different communities.