Integrated life cycle assessment-analytic hierarchy process (LCA-AHP) with sensitivity analysis of phosphorus recovery from wastewater in Metro Manila

Abstract

The adverse environmental impact caused by eutrophication has recently prompted the Philippine government to issue stringent regulatory standards for wastewater effluent quality. The involved stakeholders and industries are assessing the integration of biological nutrient removal (BNR) technologies in the current sewage treatment plant (STP) scenario. Moreover, efforts are being done to utilize wastewater as a resource such us recovery of nutrients as struvite fertilizer from the wastewater sludge. Since BNR and nutrient recovery systems are not yet integrated in STPs, the magnitude of the environmental impacts are yet to be evaluated in the Philippine setting. This study covers the holistic evaluation of the overall environmental performance scores of the following scenarios using a consequential Life Cycle Assessment (LCA) framework integrated with Analytic Hierarchy Process (AHP) in the context of Water-Energy-Food Nexus: 1) current STP scenario; 2) BNR technology; and 3) nutrient recovery system. The environmental impact assessment was done using IMPACT 2002+ methodology in terms of the following impact indicators: human health, ecosystem quality, climate change, resources, aquatic acidification, and aquatic eutrophication. Value judgments from relevant stakeholders were elicited to rank the relative importance of the impact indicators in the evaluation of the overall environmental performance score. The LCA-AHP results show that the integration of a nutrient recovery system is the most preferred scenario. Sensitivity analysis was also done to evaluate the effects of changes in diet and utilization of alternative energy.

Life cycle assessment of nutrient recovery strategies from domestic wastewaters to quantify environmental performance and identification of trade-offs

“…Sensitivity analysis was performed to evaluate the effects of the input parameters in the LCIA results 51 . In this study, the concept of Design of Experiments (DoE) was utilised to generate regression equations that could represent and explain the effects of factors to the response 52 , 53 . The factors considered are the amount of recovered fertiliser and the renewable energy percentage while the response considered is the global warming potential (GWP).…”

Life Cycle Assessment under Uncertainty: A Scoping Review

“…In Case 1, the focus was on changes in the volume of wood materials, whereas in Case 2, the focus was on simultaneous changes in the volumes of wood, steel, and concrete materials. In the context of phosphorus recovery from wastewater in Metro Manila, Pausta et al [47] evaluated the holistic environmental performance scores of the following scenarios based on the LCA framework integrated with the analytic hierarchy Process (AHP). Using the sensitivity analysis, the overall environmental impact score was evaluated using different input parameters for the LCI analysis and priority weights for the AHP method.…”

“…[75] Variation in the input parameters in the life cycle inventory (LCI) analysis and the priority weights for the AHP method concerning the overall environmental impact score. [47] The uncertainties related to the LCI data location considered by comparing LCI regionalized data to Brazil (B-LCI) and global market data, the uncertainties from errors obtained in data collection, and data quality indicators through the pedigree matrix approach.…”