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Emergy Evaluation of Nutrient Recovery from Municipal Wastewater for Sustainable Food Production Systems - An Alternative to Traditional Fertilizers
Citation:
Ma, Cissy, J. Cashdollar, A. González-Mejía, R. Theregowda, AND J. Garland. Emergy Evaluation of Nutrient Recovery from Municipal Wastewater for Sustainable Food Production Systems - An Alternative to Traditional Fertilizers. The National Academies of Science-Research Associate Program Cincinnati Visit, Cincinnati, OH, August 07 - 08, 2017.
Impact/Purpose:
Use thermodynamic accounting to evaluate the direct and indirect energy along the supply chains of struvite production from wastewater against traditional commercial fertilizers. The results provide a fundamental analysis for nutrient recovery as a sustainable alternative for water and food production. Traditional water management has often employed end-of-pipe approaches to address “water” issues. Different engineering and management instruments separately target water resources, use, treatment, and disposal; disregarding the benefits of integrating ecosystem services to water and food production systems. For instance, domestic wastewater management is exclusively focused on removing harmful substances. This approach of removal and disposal requires a high investment of energy and materials, and neglects the prospective advantages of transformation and reuse of these constituents in wastewater. One such constituent of importance is phosphorus in wastewater stream. Phosphorus comes from the metabolites of food digestion, which is extracted from phosphate rock and ultimately used in fertilizer for food production. It is estimated that phosphate rock, however, could be depleted in this century which would lead to global food crisis. Thus, in order to holistically develop sustainable water systems integrated to ecosystems services (i.e., phosphorous resources), this research evaluates fertilizer production from struvite (i.e., magnesium ammonium phosphate hexahydrate) that is generated from mixed wastewater. Further, this study compares the struvite production against traditional commercial fertilizers (e.g., diammonium phosphate). Emergy is used to provide system analysis including energy use, nutrient/eutrophication reduction, revenue stream, and whole system efficiency. This emergy analysis sheds light on the feasibility of nutrient recovery, quantifies the direct and indirect contributions, including the phosphorus rock formation, to the entire supply chain for both fertilizer production processes. The results of this research demonstrated that nutrient recovery from municipal wastewater is a sustainable alternative for water and food production systems management.
Description:
Traditional water management has often employed end-of-pipe approaches to address “water” issues. Different engineering and management instruments separately target water resources, use, treatment, and disposal; disregarding the benefits of integrating ecosystem services to water and food production systems. For instance, domestic wastewater management is exclusively focused on removing harmful substances. This approach of removal and disposal requires a high investment of energy and materials, and neglects the prospective advantages of transformation and reuse of these constituents in wastewater. One such constituent of importance is phosphorus in wastewater stream. Phosphorus comes from the metabolites of food digestion, which is extracted from phosphate rock and ultimately used in fertilizer for food production. It is estimated that phosphate rock, however, could be depleted in this century which would lead to global food crisis. Thus, in order to holistically develop sustainable water systems integrated to ecosystems services (i.e., phosphorous resources), this research evaluates fertilizer production from struvite (i.e., magnesium ammonium phosphate hexahydrate) that is generated from mixed wastewater. Further, this study compares the struvite production against traditional commercial fertilizers (e.g., diammonium phosphate). Emergy is used to provide system analysis including energy use, nutrient/eutrophication reduction, revenue stream, and whole system efficiency. This emergy analysis sheds light on the feasibility of nutrient recovery, quantifies the direct and indirect contributions, including the phosphorus rock formation, to the entire supply chain for both fertilizer production processes. The results of this research demonstrated that nutrient recovery from municipal wastewater is a sustainable alternative for water and food production systems management.