The dissolved methane recovery from treated sewage in upflow anaerobic sludge blanket (UASB) reactors: The energy demand, carbon footprint and financial cost.

The goal of this research was to quantify the energy demand and carbon footprint over the life cycle, along with the financial cost, of sewage treatment with the recovery of dissolved methane (d-CH4). The sewage treatment is composed of pre-treatment, followed by treatment in upflow anaerobic sludge blanket (UASB) reactors, trickling filter and secondary decanter, post-treatment with disinfection, and biogas recovery in the three-phase separator of the UASB reactor. The methods used in this study were attributional life cycle assessment and techno-economic analysis - LCA and TEA, respectively. The energy demand, carbon footprint and financial cost for 1 m3 sewage treatment in the evaluated scenario without d-CH4 recovery (S1) were 3.4 MJ, 1.7 kg CO2eq and 0.17 USD respectively, while those with d-CH4 recovery (S2) varied by 12%, -16% and 2.3% compared to S1. The produced biogas for lower heating value in S2 (2.6 MJ) was 27% higher than that in S1 (2.0 MJ) and this varied from 1.3 MJ to 4.6 MJ in the scenarios for different influent chemical oxygen demand (COD) in the sewage treatment plant (STP) and COD removal efficiency in the UASB reactor. The highest eco-efficiency for 1 MJ heat production from the STP biogas was achieved in the scenario with d-CH4 recovery, higher influent COD, higher COD removal efficiency in the UASB reactor, d-CH4 saturation, photovoltaic electricity supply, and a higher energy efficiency in d-CH4 recovery combined (S2,COD+,R+,S,PV,EE+), which reduced the energy demand by 55%, carbon footprint by 66% and financial cost by 63% compared to S1. Furthermore, the STP functionality change from a single-product (biogas) to a multi-product (biogas, water for reuse and biosolid fertilizer) approach (S1,WR, BF and S2,WR,BF) made the biogas a competitive product compared to those from fossil sources. Therefore, resource recovery from the sewage treatment in higher influent COD, higher COD removal efficiency, the use of a more efficient, clean and economical electricity source and higher energy efficiency in d-CH4 recovery in a multi-product STP contribute to achieving the energy self-sufficiency over the life cycle while reducing the carbon footprint and financial cost of its products.

Environmental assessment of on-site source-separated wastewater treatment and reuse systems for resource recovery in a sustainable sanitation view.

Sustainable sanitation solutions are necessary for promoting public health and environmental security. In this study, on-site domestic wastewater treatment (WWT) systems used for households in rural and peri-urban areas of Brazil were compared in different scenarios from a life cycle assessment (LCA) perspective. The evaluated scenarios represented different practices in wastewater management, such as direct discharge into the soil, rudimentary treatment, septic tank, public sewerage system, and source separation of wastewater streams for water, nutrient, and organic matter recovery. The WWT technologies considered in the proposed scenarios of source-separated wastewater streams were as follows: an evapotranspiration tank (TEvap) and composting toilet for blackwater, a modified constructed wetland (EvaTAC) for greywater, and a storage tank for urine. LCA was performed in this study according to the ISO standards to assess the environmental impacts at both midpoint and endpoint levels. The results show that on-site source-separated wastewater treatment systems with resource recovery result in significant reductions in environmental impacts compared to scenarios with precarious conditions or 'end-of-pipe' solutions. For example, regarding the human health damage category, the scenarios involving resource recovery, including systems such as EvaTAC, TEvap, composting toilet, and urine storage tank, demonstrate significantly lower values (-0.0117 to -0.0115 DALY) compared to scenarios with rudimentary cesspits and septic tanks (0.0003 to 0.001 DALY). We conclude that the focus should be beyond mere pollution aspects and instead concentrate on the benefits of the co-products, which are: avoiding the extraction and consumption of valuable and increasingly scarce raw materials, such as potable water, and production of synthetic fertilizer. Furthermore, it is highly recommended that an LCA of sanitation systems synergistically integrates the WWT process, the constructive aspects, and the resource recovery potential.

Human urine fertiliser in the Brazilian semi-arid: Environmental assessment and water-energy-nutrient nexus.

This manuscript aimed to identify the energy demand, and environmental aspects and impacts of crop fertilisation with human urine when compared to using mineral fertilisers. The Material Flow Analysis and Life Cycle Assessment methods were adopted covering the options from "cradle to grave". The fertilisation with human urine included the collection, storage, transportation, application and field emissions, while the fertilisation with mineral fertilisers included primary production of fertilisers, transportation, application and field emissions. The reference flows were based on the fertilisation of 1 ha of maize with 225 kg of nitrogen, 29 kg of phosphorus and 48 kg of potassium oxide. We analysed the environmental aspects such as nitrogen and phosphorus mass balance, energy demand and water depletion, as well as environmental impacts such as global warming, human toxicity, photochemical ozone formation, acidification, eutrophication, freshwater ecotoxicity, water scarcity and resource depletion. The agricultural fertilisation with full volume of human urine closer to the source presented smaller energy demand and environmental impact indicator values when compared to solid mineral fertiliser, despite the uncertainties. The fertilisation with human urine was more advantageous with transportation distances up to 134 km (energy demand) and 84 km (environmental categories) by truck compared to 1841 km of mineral fertiliser. Ammonia volatilisation control was key to reduce acidification and eutrophication indicator values. When considering additional gains such as the reduction of water demand and wastewater generation from a waterless collection of human urine, the indicator values of environmental aspects and impacts of fertilisation with human urine were smaller than those with mineral fertiliser and reached a break-even point of 193 km (energy demand) and 185 km (environmental categories). The nutrient cycling through resource-based sanitation offers an opportunity to expand sanitation access with smaller environmental impacts and more efficient water-energy-nutrient nexus.

Environmental improvement in the printing industry: the case study of self-adhesive labels.

Labels are used for marketing, technical information, local of production and environmental declarations of products. The aim of the study was to evaluate the life cycle of two sets of front and back adhesive labels made with different liners: polyethylene terephthalate (PET) and glassine paper. The study is a pioneering initiative in the labelling industry using life cycle assessment, especially in Brazil. The attributional life cycle assessment method was based on the ISO 14044 standard and covered the entire life cycle, cradle to grave. Primary data for key suppliers, printing facility and label use composed the foreground data, while the ecoinvent database composed the background data. The material efficiency was assessed through mass balance. The impact assessment methods were cumulative energy demand for non-renewable energy and ILCD 2011 midpoint for the environmental categories. The glassine liner is heavier than the PET which resulted in larger environmental indicator values for production, transportation and waste treatment. On the other hand, energy demand of label set with glassine liner was lower than the PET. Furthermore, the hotspot analysis of each impact category was presented per process and substance. The label set made with glassine liner tended to present larger environmental indicator values in most categories, 13 of the 16 assessed, compared to the label set made with PET liner, despite the uncertainties. Contribution analysis identified that the pre-manufacturing step presented larger environmental indicator values than manufacturing, use and post-use steps along the label set life cycle. Therefore, environmental improvement opportunities were evaluated through scenarios of end of life, recycled inputs, domestic suppliers, waste prevention and product redesign. Moreover, the life cycle assessment was useful for diagnosing the energy and environmental profiles of self-adhesive labels and planning cleaner production measures that avoid environmental tradeoffs.

Gerenciamento de resíduos sólidos urbanos de Feira de Santana: demanda energética e pegada de carbono / Management of solid urban waste in Feira de Santana: energy demand and carbon footprint

RESUMO O gerenciamento de resíduos sólidos urbanos, com a disposição do material em aterro sanitário, é uma prática amplamente adotada no Brasil. A quantificação do desempenho ambiental do gerenciamento de resíduos sólidos urbanos apoia a proposição de práticas otimizadas. A avaliação do ciclo de vida foi aplicada para avaliar o gerenciamento de resíduos sólidos urbanos de 1 tonelada de material em Feira de Santana, estado da Bahia, Brasil. A fronteira do sistema do gerenciamento de resíduos sólidos urbanos deste estudo incluiu o material gerenciado nas etapas de coleta, transporte, tratamento, disposição e manejo do lixiviado. Foi avaliada a disposição do material em aterro sanitário no cenário base de gerenciamento de resíduos sólidos urbanos e opções de recuperação de recurso para o aproveitamento de material (reciclagem e compostagem) e energia (aterro sanitário e digestão anaeróbia com coleta de biogás) nos cenários propostos de gerenciamento de resíduos sólidos urbanos. O inventário de primeiro plano utilizou dados representativos para os cenários avaliados, enquanto o inventário de segundo plano utilizou a base de dados ecoinvent™ no software Simapro®, com os métodos de demanda de energia acumulada e Intergovernmental Panel On Climate Change 2013, com potencial de aquecimento global de cem anos. A demanda de energia acumulada foi 215 MJ·t-1 e as emissões de gases de efeito estufa foram 449 kg CO2eq·t-1 no cenário base. A maior contribuição da demanda de energia acumulada do cenário base foi oriunda da etapa de coleta e transporte, enquanto aquela de gases de efeito estufa foi oriunda do aterro sanitário. Os cenários propostos com a recuperação dos recursos apresentaram potenciais de redução da demanda de energia acumulada e das emissões de gases de efeito estufa do gerenciamento de resíduos sólidos urbanos, assim como apoiam a transição para uma economia circular.

ABSTRACT Municipal Solid Waste Management with the material disposal in landfills is a widely adopted practice in Brazil. The environmental performance quantification in MSWM supports the proposition of optimized practices. The Life Cycle Assessment was applied to evaluate 1 ton of material in the Municipal Solid Waste Management of Feira de Santana, state of Bahia, Brazil. The system boundary of the Municipal Solid Waste Management in this study included the material managed in collection, transportation, treatment, disposal and leachate handling stages. The material disposal in sanitary landfill was evaluated in the base scenario of Municipal Solid Waste Management and the resource recovery options for material (recycling and composting) and energy (sanitary landfill and anaerobic digestion with biogas collection) in the proposed scenarios of Municipal Solid Waste Management. The foreground inventory used representative data for the evaluated scenarios, while the background inventory used the ecoinvent™ database in the Simapro® software with the Cumulative Energy Demand and Intergovernmental Panel on Climate Change 2013 with 100 years global warming potential methods. Cumulative Energy Demand was 215 MJ·t-1 and Greenhouse Gas emissions were 449 kg CO2eq·t-1 in the base scenario. The largest contribution in the base scenario was the collection and transportation stage in Cumulative Energy Demand and the sanitary landfill in Greenhouse Gas. The proposed scenarios with resource recovery showed a potential to reduce the Cumulative Energy Demand and Greenhouse Gas emissions in Municipal Solid Waste Management, along with supporting the transition to a circular economy.

Desempenho energético e pegada de carbono de um sistema de esgotamento sanitário centralizado no nordeste brasileiro / Energy performance and carbon footprint of a centralized sewage system in northeastern Brazil

RESUMO O objetivo do trabalho foi avaliar a operação e manutenção de um sistema de esgotamento sanitário centralizado, composto de três subsistemas, que atende 367 mil habitantes no Nordeste do Brasil. A avaliação do ciclo de vida considerou um inventário amplo de operação e manutenção do sistema de esgotamento sanitário com as redes de coleta, estações de tratamento de esgoto, disposição do esgoto tratado no corpo hídrico e gestão do lodo. O arranjo tecnológico das estações de tratamento de esgoto avaliadas incluiu o reator do tipo upflow anaerobic sludge blanket, seguido de lagoa aerada e lagoa de polimento em um subsistema, e upflow anaerobic sludge blanket seguido de reator de lodo ativado por aeração prolongada em dois subsistemas. O desempenho energético utilizou o método de demanda de energia acumulada e a pegada de carbono empregou o método de potencial de aquecimento global de 100 anos do Painel Intergovernamental sobre Mudanças Climáticas. O sistema de esgotamento sanitário avaliado demandou 5,12 MJ·m−3 e emitiu 4,08 kg CO2eq·m−3. As maiores contribuições do sistema de esgotamento sanitário avaliado foram a eletricidade, com 62% da demanda energética, e as emissões diretas para o ar, com 94% da pegada de carbono, sendo as emissões dos reatores upflow anaerobic sludge blanket com 76% da pegada de carbono. A identificação dos aspectos e impactos ambientais do sistema de esgotamento sanitário avaliado apoia a inovação tecnológica e gerencial para otimizar o desempenho energético e mitigar as emissões de gases de efeito estufa.

ABSTRACT This aim of this work was to evaluate the operation and maintenance of a centralized wastewater treatment system, composed of three subsystems, which serves 367 thousand inhabitants in northeastern Brazil. The life cycle assessment considered a comprehensive inventory of the wastewater treatment system operation and maintenance with the collection networks, wastewater treatment plants, disposal of the treated wastewater in the water body and sludge management. The technological arrangement of the evaluated wastewater treatment plants included the Upflow Anaerobic Sludge Blanket reactor, followed by aerated and polishing ponds in one subsystem, and Upflow Anaerobic Sludge Blanket followed by extended aeration activated sludge in two subsystems. The energy performance used the cumulative energy demand method and the carbon footprint used the global warming potential method for 100 years of the Intergovernmental Panel on Climate Change. The evaluated wastewater treatment system presented 5.12 MJ·m−3 and 4.08 kg CO2eq·m−3. The largest contribution of the evaluated wastewater treatment system was the electricity use with 62% of the energy demand and direct emissions to the air with 94% of the carbon footprint, being direct emissions from Upflow Anaerobic Sludge Blanket reactors with 76% of the carbon footprint. The identification of environmental aspects and impacts of the evaluated wastewater treatment system supports technological and management innovations to optimize its energy performance and mitigate greenhouse gases emission.

Avaliação energética de um sistema integrado de abastecimento de água / Energy evaluation of an integrated water supply system

RESUMO Os encargos energéticos decorrentes do Sistema Integrado de Abastecimento de Água de Feira de Santana (SIAA-FSA) foram analisados utilizando o método de avaliação do ciclo de vida. Foram identificadas, na cadeia de abastecimento de água, as etapas do sistema com maiores encargos energéticos, e propostos cenários de melhoria. Cadeias de produção dos insumos químicos, transporte dos insumos, energia elétrica e substituição dos tubos na rede para a manutenção do SIAA-FSA foram consideradas. A demanda energética acumulada do SIAA-FSA foi de 3,51 kWh.m-3 de água consumida. As etapas de captação e distribuição de água apresentaram os maiores consumos energéticos, e a eletricidade do bombeamento representou 86% da demanda energética acumulada. Os cenários propostos para o SIAA-FSA apresentaram melhorias significativas em relação ao cenário atual, com usos mais racionais de insumos químicos, eletricidade e água.

ABSTRACT The energy burdens of the Feira de Santana Integrated Water Supply System (SIAA-FSA) were analyzed using the life cycle assessment method. The higher energy burdens in the water supply chain were identified and scenarios for improvement were proposed. The supply chain of chemicals, transportation, electricity and replacement of pipes were considered for SIAA-FSA. The cumulative energy demand of SIAA-FSA was 3.51 kWh.m-3 of consumed water. The water uptake and distribution steps presented the highest energy demands, and the electricity for pumping represented 86% of the cumulative energy demand. The SIAA-FSA proposed scenarios showed significant improvements over the current one, with rational use of chemicals, electricity and water.

Life cycle analysis to evaluate the productive chain of fish consumed in the Bahia State (Brazil) / Análise do ciclo de vida para avaliar a cadeia produtiva do pescado consumido no estado da Bahia (Brazil)

We evaluated the productive chain of fish consumed in the State of Bahia using Life Cycle Analysis (LCA). We estimated the inputs and outputs from logistics and fish processing. For every kg of processed and transported fish we calculated the Global Warming Potential (GWP) based on the amount of Greenhouse Gases (GHG) given in kg of CO2eq, as follows: 0.020 electricity; 0.003 water consumption; 0.002 wastewater; 0.160 and 1.495 waste from the gutted and filleted fish, respectively; 0.871 and 1.007 refrigerated transportation of gutted and filleted fish, respectively. The sum of GHG emissions were 1.058 and 2.592 kg of CO2eq per kg of gutted and filleted fish, respectively. LCA results indicate that it is possible to reduce the GWP associated with refrigerated transportation by increasing local fish production and decreasing importation, especially given the available water potential of Bahia. However, to achieve a sustainable production it is imperative to adopt and also develop technologies that promote environmental impact reduction from solid residues.(AU)

Avaliamos a cadeia produtiva do pescado consumido no Estado da Bahia utilizando a Análise de Ciclo de Vida (ACV). Estimamos os consumos e emissões associados à logística e ao processamento do peixe. O Potencial de Aquecimento Global (PAG) foi calculado com base na quantidade de Gases Efeito Estufa (GEE) indicadas por kg de CO2eq para cada kg de peixe processado foram: 0,020 - eletricidade; 0,003 consumo de água; 0,0029 efluentes; 0,160 e 1,495 resíduos sólidos para os peixes eviscerados e filetados, respectivamente, e 0,871 e 1,007 transporte refrigerado dos peixes eviscerados e filetados, respectivamente. O somatório do impacto das emissões de GEE foram 1,058 e 2,529 kg de CO2eq por kg de peixe eviscerado e filetado, respectivamente. Os resultados indicaram que é possível reduzir o PAG do transporte refrigerado com o aumento da produção local de peixe e redução das importações, especialmente considerando o potencial hídrico da Bahia. Entretanto, a produção sustentável requer a adoção e desenvolvimento de tecnologias para reduzir os impactos ambientais do tratamento dos resíduos sólidos da etapa de processamento.(AU)

Life cycle analysis to evaluate the productive chain of fish consumed in the Bahia State (Brazil) / Análise do ciclo de vida para avaliar a cadeia produtiva do pescado consumido no estado da Bahia (Brazil)

We evaluated the productive chain of fish consumed in the State of Bahia using Life Cycle Analysis (LCA). We estimated the inputs and outputs from logistics and fish processing. For every kg of processed and transported fish we calculated the Global Warming Potential (GWP) based on the amount of Greenhouse Gases (GHG) given in kg of CO2eq, as follows: 0.020 electricity; 0.003 water consumption; 0.002 wastewater; 0.160 and 1.495 waste from the gutted and filleted fish, respectively; 0.871 and 1.007 refrigerated transportation of gutted and filleted fish, respectively. The sum of GHG emissions were 1.058 and 2.592 kg of CO2eq per kg of gutted and filleted fish, respectively. LCA results indicate that it is possible to reduce the GWP associated with refrigerated transportation by increasing local fish production and decreasing importation, especially given the available water potential of Bahia. However, to achieve a sustainable production it is imperative to adopt and also develop technologies that promote environmental impact reduction from solid residues.

Avaliamos a cadeia produtiva do pescado consumido no Estado da Bahia utilizando a Análise de Ciclo de Vida (ACV). Estimamos os consumos e emissões associados à logística e ao processamento do peixe. O Potencial de Aquecimento Global (PAG) foi calculado com base na quantidade de Gases Efeito Estufa (GEE) indicadas por kg de CO2eq para cada kg de peixe processado foram: 0,020 - eletricidade; 0,003 consumo de água; 0,0029 efluentes; 0,160 e 1,495 resíduos sólidos para os peixes eviscerados e filetados, respectivamente, e 0,871 e 1,007 transporte refrigerado dos peixes eviscerados e filetados, respectivamente. O somatório do impacto das emissões de GEE foram 1,058 e 2,529 kg de CO2eq por kg de peixe eviscerado e filetado, respectivamente. Os resultados indicaram que é possível reduzir o PAG do transporte refrigerado com o aumento da produção local de peixe e redução das importações, especialmente considerando o potencial hídrico da Bahia. Entretanto, a produção sustentável requer a adoção e desenvolvimento de tecnologias para reduzir os impactos ambientais do tratamento dos resíduos sólidos da etapa de processamento.