Environmental Sustainability Assessment of Technologies for Removal of Contaminants of Emerging Concern

Current regulations on water quality are primarily based on the reduction of priority pollutants for water quality pretention and all other side impacts and/or benefits associated with pollutants removal are generally not considered in process selection, design and compliance regulation. The rising health concerns with contaminants of emerging concern (CECs) have motivated regulation initiatives as well as development of CECs remediation technologies. Both high-level nutrient removal and CECs removal require advanced tertiary processes, which in general are highly energy-and chemical-intensive. High usage of chemical and energy in these processes are associated with the increased life cycle toxicity and other environmental impacts. It is necessary to evaluate the balance between benefits achieved from removal of nutrients and CECs, and environmental costs due to additional chemical, energy and materials usage. This study evaluates the environmental and health impact associated with a range of advanced wastewater treatment processes that are designed for both nutrients removal and additional CECs removal through life cycle analysis as would be in real wastewater treatment scenarios. A total of 31 typical 10 MGD treatment plants were designed considering typical US influent wastewater parameter which cover three different levels of nutrient removal processes with or without the additional tertiary processes of CECs removal. Benefits achieved through the reduction of eutrophication potential by reducing nutrient from the wastewater and toxicity reduction through the removal of CECs during treatment processes are considered simultaneously. Environmental costs were estimated in terms of the increase in eutrophication, eco and human toxicity and global warming potential from the adopted treatment processes. From the analyses it is observed that the benefits achieved from the reduction of eutrophication through nutrient removal can be outweighed by the adoption of tertiary process to remove CECs. On the contrary though a very little improvement due to toxicity reduction achieved through the removal of the CECs, the high amount of energy and chemical usage in the tertiary processes produces higher toxicity compared to the benefits achieved. Uncertainty analysis was performed considering the limited understanding and wide range of removal efficiencies observed for different CECs removal through different wastewater treatment processes.