Life Cycle Assessment of Hybrid-Biological Wastewater Treatment Plants: Challenges and Opportunities

Primarily propelled by the growing population, wastewater generation has been continuously increasing. Rapid urbanization and industrial development are also increasing the load on the existing wastewater treatment plants (WWTPs). Henceforth, the pursuit of sustainable development goals, aided by technological advancements, has fuelled the construction of new WWTPs, along with the transformation of the existing conventional WWTPs into hybrid-biological treatment plants, which has emphasized the domains of resource recovery and circular economy. However, it is crucial to ensure that the overall environmental impact of the modified WWTP is lower than that of the conventional one. Life Cycle Assessment (LCA) serves as a tool that quantitatively assesses the anticipated environmental impact of WWTPs and facilitates comparisons with their conventional counterparts. This book chapter provides an overview of the LCA methodology within the context of WWTPs, highlighting the iterative nature of the different phases of an LCA, along with a detailed discussion of the individual phase. The environmental impact of employing hybrid-biological wastewater treatment units was discussed with the aid of case studies on nutrient removal, constructed wetlands, moving bed biofilm reactors and membrane bioreactors. Apart from highlighting the trade-offs inherent to different hybrid systems, the chapter also emphasizes the challenges associated with data availability, quality and acceptability of the LCA results while underscoring the associated methodological challenges. Therefore, this chapter can aid researchers, policymakers and academicians alike in understanding the intricacies associated with the LCA of WWTPs and support better decision-making.