Assessment of direct and indirect emissions from the wastewater treatment plant and sludge processing: A case study

Due to rapid urbanisation and population, a constant supply of clean and fresh water has come under stress. Raw water must be continuously treated and supplied to satisfy the day-to-day needs for potable water for household use. To find a solution to the issue, several governments worldwide have moved their focus to water and sanitation. Large sewage and effluent treatment facilities are continuously working to treat wastewater, which is the most crucial step in addressing the problem of fresh water. Sludge is the main by-product produced by these treatment plants, which creates a challenge when it comes to disposal. The sludge is processed in the treatment facilities before being disposed of, allowing for better waste management. In the treatment process of the wastewater, from the moment the wastewater enters the treatment facility until the sludge is disposed of, there are multiple points at which emissions are produced. These emissions need to be evaluated and dealt with, as they have the potential to significantly impact climate change and the depletion of the ozone layer. The authors have analysed the emissions using several methodologies, including IPCC inventories, life cycle assessment, and many more. The study's findings indicate that a significant quantity of greenhouse gas emissions (directly and indirectly) and air pollutants are emitted during the process of treating wastewater and disposal of sludge.