Low complexity wastewater treatment process in developing countries: A LCA approach to evaluate environmental gains.

Reliable Life Cycle Assessment (LCA) indicators for wastewater treatment plants (WWTP) construction and operation phases are still a demand mainly in developing countries. Thus, the purpose of this paper was to present and discuss the environmental performance of a full-scale WWTP installed in a Brazilian city using LCA approach. The treatment process consists of a UASB reactor followed by constructed wetlands, which makes it particularly attractive to developing countries due to its operational simplicity. The Life Cycle Inventory (LCI) was developed from a WWTP design and operation data including those of untreated wastewater and effluent quality. The results show that the environmental impacts from construction phase should not be neglected in LCA studies of low complexity treatment technologies (e.g. UASB reactor, constructed wetlands and pond systems). There is a trade-off between the use of materials and energy for construction and the low energy and materials consumption during the operation phase in these systems. The majority share of hydroelectric generation in the energy matrix and the combination of anaerobic and natural processes for wastewater treatment have contributed to a smaller impact potential for the operation phase. The LCA approach should be associated with plans and actions to face the challenges of providing wastewater treatment in developing countries. Only in this way, compliance with the eco-efficiency targets and protect public health will be guaranteed.

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.

Avaliação de parâmetros operacionais de um sistema de membranas para tratamento de efluentes oleosos / Evaluation of a membrane system's operational parameters for oily effluent treatment

RESUMO O objetivo deste trabalho foi discutir os principais parâmetros de controle de um sistema de membranas de microfiltração para remoção de óleo de efluentes com base em ensaios experimentais. Os ensaios utilizaram efluentes sintéticos com diâmetros de gotas de óleo entre 4 e 8 µm. As membranas usadas foram do tipo fibra oca com módulo submerso. Foram testados os seguintes parâmetros: concentrações de óleos e graxas na alimentação das membranas (O&Gam) entre 100 e 260 mg.L-1; taxas de recuperação de água (Rec) de 0,75 e 0,90; e pressões através das membranas (Δp) de -0,20 e -0,30 bar. Os resultados mostraram que as membranas produzem um permeado com uma qualidade boa a ponto de possibilitar o seu reúso em atividades industriais diversas. Foi também observado que a elevação da O&Gam e da Rec acentuam o declínio de fluxo com o tempo e que a elevação da Δp aumenta o valor do fluxo no tempo de seis horas.

ABSTRACT The aim of this paper is to discuss the main control parameters of a microfiltration membranes system for oil removal from effluent on experimental bases. The experiments were conducted by using synthetic effluent with oil droplets diameter ranging from 4 to 8 microns. The membranes used were hollow fiber-type which were assembled in a submerged module. The following parameters were tested: Oil and grease concentration in the feed stream (O&Gf ) of 100 and 200 mg.L-1, Water recovery rates (WRR) of 0.75 and 0.90, and Transmembrane pressure (TMP) of -0.20 and -0.30 bar. The results showed that the membranes produced a permeate with a good quality to the point of enabling their reuse in several industrial activities. It was also observed that the elevation of O&Gf and WRR increase the flux decline over time and that the increase of TMP increases the flow value in time of 6 hours.

O Programa AGUAPURA de racionalização do consumo de água da Universidade Federal da Bahia / The AGUAPURA Program for water consumption rationalization at the Federal University of Bahia

RESUMO Este artigo descreve e discute os métodos usados, as dificuldades encontradas e os resultados obtidos em um programa de racionalização do uso da água desenvolvido por um programa de pesquisa da Universidade Federal da Bahia. Na universidade, foi alcançada redução de até 49% no consumo per capita. No aeroporto e em um shopping center de Salvador foram identificados cenários de reduções ainda maiores. Pesquisa de opinião justifica a admissão de alternativas inovadoras de grande impacto. Em um conjunto de prédios do Governo do Estado da Bahia as reduções atingiram 55, 72 e 82% nos três prédios mais comprometidos com o projeto. Os resultados obtidos levaram o Governo do Estado a estender o projeto a todos os seus prédios administrativos e às escolas públicas estaduais.

ABSTRACT This article describes and discusses methods, results obtained and difficulties found in a water-use rationalization program developed by a research program at the Federal University of Bahia. At the University we obtained a reduction of up to 49% in per capita consumption. At the airport and in a shopping center in Salvador we identified other scenarios for further reductions. Opinion survey justifies the admission of innovating high-impact alternatives. In a set of buildings of the State Government of Bahia, reductions reached 55, 72 and 82% in the three buildings most committed to the project. The results led the State Government to extend the project to all its administrative buildings and public schools.

Strategies for thermal comfort in university buildings - The case of the faculty of architecture at the Federal University of Bahia, Brazil.

Buildings constructed according to bioclimatic architectural principles in amenable climates have often experienced posterior interventions that have closed ventilation openings for the installation of air conditioning units. The present work sought to investigate the reasons for installing air conditioning equipment in buildings even under adverse economic conditions and with the awareness of their negative environmental implications. The Faculty of Architecture building at the Federal University of Bahia, located in the city of Salvador, Bahia State, Brazil, was the focus of the present investigation. It was determined that the lack of maintenance of the windows and window frames, and the closing of projected openings compromised natural ventilation. The study confirmed the adequacy of the architectural project in relation to the local climate, and in loco measurements likewise confirmed the efficiency of natural ventilation through the windows and other openings in the faculty room and classrooms examined. The results of the interviews concerning thermal comfort indicated that 53% of the users felt comfortable. Nonetheless, it was found that the building's windows and window frames were poorly maintained, compromising their ability to facilitate efficient natural ventilation and significantly diminishing the capacity for thermal regulation in the building. This study calls attention to the necessity of refining and improving the maintenance of university buildings to reduce the intensive use of artificial air conditioning in detriment to investments in projects that could lend priority to natural ventilation and the maintenance of good window operating conditions.

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.

Hydroelectric production from Brazil's São Francisco River could cease due to climate change and inter-annual variability.

By the end of this century higher temperatures and significantly reduced rainfall are projected for the Brazilian North and Northeast (NE) regions due to Global Warming. This study examines the impact of these long-term rainfall changes on the Brazilian Northeast's hydroelectric production. Various studies that use different IPCC models are examined in order to determine the average rainfall reduction by the year 2100 in comparison to baseline data from the end of the 20th century. It was found that average annual rainfall in the NE region could decrease by approximately 25-50% depending on the emissions scenario. Analysis of historical rainfall data in the São Francisco basin during the last 57years already shows a decline of more than 25% from the 1961-90 long-term average. Moreover, average annual rainfall in the basin has been below its long-term average every year bar one since 1992. If this declining trend continues, rainfall reduction in the basin could be even more severe than the most pessimistic model projections. That is, the marked drop in average rainfall projected for 2100, based on the IPCC high emissions scenario, could actually eventuate before 2050. Due to the elasticity factor between rainfall and streamflow and because of increased amounts of irrigation in the São Francisco basin, the reduction in the NE's average hydroelectric production in the coming decades could be double the predicted decline in rainfall. Conversely, it is estimated that wind power potential in the Brazilian NE will increase substantially by 2100. Therefore both wind and solar power will need to be significantly exploited in order for the NE region to sustainably replace lost hydroelectric production.

Decision support system for management of reactive nitrogen flows in wastewater system.

The change in nitrogen balance causes many environmental and socioeconomic impacts. In relation to food production and nitrogen release in wastewater systems, wastewater and sludge discharge and mineral fertilizer use intensify nitrogen imbalance of a region. The replacement of mineral fertilizer by nitrogen from treated wastewater, biosolids, and treated urine is a promising alternative. This work presents a model to support decision taking for the management of reactive nitrogen flows in wastewater systems based on system dynamics. Six scenarios were simulated for nitrogen flows in wastewater systems and related components.

Metodologia TECLIM para uso racional de água na indústria: o banco de ideias no contexto da metodologia front-end loading / TECLIM method for rational water use in industry: the bank of ideas in the context of the front-end loading methodology

RESUMO O banco de ideias (BI) é uma ferramenta da metodologia TECLIM para otimização ambiental de processos industriais. Está conceitualmente associado com a metodologia front-end loading (FEL), a qual considera que forte atenção nas etapas iniciais de identificação e seleção de alternativas aumenta as chances de sucesso de um projeto, evitando que recursos sejam desperdiçados ou mal alocados. O BI abrange a etapa FEL 1, na qual é feito o levantamento de ideias, e segue até parte da etapa FEL 2, na qual as oportunidades selecionadas são desenvolvidas a projetos conceituais. O método para priorização de oportunidades no BI é apresentado demonstrando-se a sinergia com a FEL. A aplicação do BI permitiu o cadastro e processamento de 500 ideias com potencial de redução do consumo de água em 1,4 x 103 t.h-1 e de efluentes em pelo menos 0,5 x 103 t.h-1. O BI direciona recursos para projetos conceituais mais atrativos e sustentáveis.

ABSTRACT The bank of ideas (BI) is a TECLIM tool for environmental optimization of industrial processes. It is conceptually associated with the front-end loading (FEL) methodology, which pays particular attention to the initial stage of identification and selection of alternatives of water use, increasing the chances of a project´s success, avoiding wasted or badly allocated resources. The BI covers FEL 1 stage, in which the ideas are invited, followed by stage FEL 2, in which the opportunities selected are developed into conceptual projects. The method of giving priorities to the opportunities in the BI is presented, showing the synergy with FEL. The application of the BI enabled the register and process of 500 ideas with the potential to reduce water consumption by 1.4 x 103 t.h-1 and effluents by at least 0.5 x 103 t.h-1. The BI tool helps to identify the most attractive and sustainable conceptual projects.

Utilização de coalescedor com leito de resinas de trocas catiônicas para pré-tratamento de óleo emulsionado em efluentes líquidos / Use of coalescer with a bed made of cationic exchange resins for pre-treatment of emulsified oil from oily wastewater

O tratamento de efluentes com coalescedor de leito consiste em induzir o aumento das gotas de óleo, pela passagem da emulsão por um leito poroso, para que elas possam, posteriormente, flotar por processo de separação gravitacional. O objetivo deste artigo foi apresentar considerações técnicas e experimentais sobre o uso do coalescedor de leito granular, com leito constituído por resinas de trocas catiônicas, visando o pré-tratamento de óleo emulsionado em efluentes líquidos. Os testes ocorreram em uma unidade em escala de bancada alimentada com emulsão óleo em água (O/A) com um teor de óleos e graxas (TOG) entre 200 e 400 mg.L-1 e diâmetro de gotas entre 3 a 8 μm. As velocidades do fluido (v) testadas foram entre 4,4 e 17,4 m.h-1. A altura do leito do coalescedor foi fixada em 5 cm. Os parâmetros usados para avaliar a eficiência dos testes foram eficiência de remoção de óleo (%E), pressão diferencial através do leito (Δp) e permeabilidade do leito (ko). Os resultados mostraram que o processo operou em estado estacionário e que os valores de TOG testados influenciaram no processo, bem como as velocidades do fluido, cuja elevação reduziu a eficiência significativamente. Os valores aproximados de %E obtidos foram 50 e 20-30%, para valores de v de 4,4 e 17,4 m.h-1, respectivamente.

The wastewater treatment with a bed coalescer consists of inducing the increase of oil droplets by passing the emulsion through a porous bed, so they can flote by gravitational separation process. The objective of this paper is to present technical and experimental considerations on the use of a granular bed coalescer, with a bed made of cationic exchange resins, for pre-treatment of emulsified oil from oily wastewater. Tests were conducted on a bench scale unit, which was fed with oil in water emulsion with oil and grease concentration (O & G) between 200 and 400 mg.L-1 and oil droplet diameter between 3 and 8 μm. The fluid velocities (v) tested were between 4.4 and 17.4 m.h-1. The coalescer bed height was fixed at 5 cm. The parameters used for assessing the tests efficiency were oil removal efficiency percentage (%E), differential pressure across the bed and, bed permeability. Results showed that the process operates in a steady-state condition and that the influent O&G affected the process efficiency, as well as the fluid velocities which reduced the efficiency significantly, with its increasing. The %E values obtained ​​were between 50 and 20-30% to v between 4.4 and 17.4 m.h-1, respectively.

Estimating the potential water reuse based on fuzzy reasoning.

Studies worldwide suggest that the risk of water shortage in regions affected by climate change is growing. Decision support tools can help governments to identify future water supply problems in order to plan mitigation measures. Treated wastewater is considered a suitable alternative water resource and it is used for non-potable applications in many dry regions around the world. This work describes a decision support system (DSS) that was developed to identify current water reuse potential and the variables that determine the reclamation level. The DSS uses fuzzy inference system (FIS) as a tool and multi-criteria decision making is the conceptual approach behind the DSS. It was observed that water reuse level seems to be related to environmental factors such as drought, water exploitation index, water use, population density and the wastewater treatment rate, among others. A dataset was built to analyze these features through water reuse potential with a FIS that considered 155 regions and 183 cities. Despite some inexact fit between the classification and simulation data for agricultural and urban water reuse potential it was found that the FIS was suitable to identify the water reuse trend. Information on the water reuse potential is important because it issues a warning about future water supply needs based on climate change scenarios, which helps to support decision making with a view to tackling water shortage.

Tratamento de água produzida de petróleo para remoção de óleo por processos de separação por membranas: revisão / Produced water treatment for oil removal by membrane separation process: review

O gerenciamento da água produzida (AP) de petróleo se constitui em um enorme desafio para as empresas petrolíferas. As alternativas usualmente adotadas para o seu destino são o descarte, injeção e o reúso. Em todos os casos é necessário tratamento da AP, a fim de evitar danos ao meio ambiente e às instalações de produção ou a fim de permitir o seu reúso sem causar prejuízos aos processos nos quais a AP será utilizada. Os processos de separação por membranas (PSM) têm se mostrado capazes de tratar efluentes que apresentam elevados teores de óleo em emulsão e de partículas com tamanhos médios e pequenos, competindo, assim, com tecnologias de tratamento mais complexas, tais como flotação. O objetivo deste artigo foi apresentar uma revisão sobre o tratamento de AP utilizando os PSM discutindo os principais aspectos da AP e os aspectos conceituais dos PSM, com ênfase para sua aplicação para remoção de óleo da AP.

The management of oil produced water (PW) constitutes a major challenge to oil companies. The options usually adopted for PW are disposal, injection and reuse. In all cases, a PW treatment is required in order to avoid damages to the environment and to production facilities or to allow its reuse without causing damage to processes in which the PW is used. The membrane separation processes (MSP) has been shown to be capable of treating effluent with high content of emulsified oil and with medium and small sizes particle, competing well with more complex treatment technologies such as flotation. The aim of this paper was to present a review of the PW treatment by MSP, discussing the main aspects of the PW and the conceptual aspects of the MSP, with emphasis on their application for removal of oil from the PW.

Comparative energy life-cycle analyses of microalgal biomass production in open ponds and photobioreactors.

An analysis of the energy life-cycle for production of biomass using the oil-rich microalgae Nannochloropsis sp. was performed, which included both raceway ponds, tubular and flat-plate photobioreactors for algal cultivation. The net energy ratio (NER) for each process was calculated. The results showed that the use of horizontal tubular photobioreactors (PBRs) is not economically feasible ([NER]<1) and that the estimated NERs for flat-plate PBRs and raceway ponds is >1. The NER for ponds and flat-plate PBRs could be raised to significantly higher values if the lipid content of the biomass were increased to 60% dw/cwd. Although neither system is currently competitive with petroleum, the threshold oil cost at which this would occur was also estimated.

Redes neurais artificiais aplicadas ao processo de coagulação / Artificial neural networks applied to the coagulation process

A coagulação é uma etapa de tratamento da água, e para tal são realizados ensaios de teste de jarro que permitem determinar a dose necessária dos agentes coagulante e químico de ajuste de pH no processo de coagulação. Contudo, esses ensaios demoram a ser executados, não respondendo em tempo real às mudanças da qualidade da água bruta. Para superar tal limitação, redes neurais artificiais multicamadas foram construídas (e seus pesos sinápticos ajustados), validadas e testadas para predizer a dosagem do hidróxido de sódio e do sulfato de alumínio - utilizados como agentes químico de ajuste de pH e coagulante, respectivamente. Os resultados dos modelos obtidos são compatíveis com os dados experimentais tendo em vista que as incertezas das estimativas estão na mesma ordem de grandeza das faixas indicadas pelos ensaios realizados de testes de jarro ao longo de quase seis anos.

Coagulation is a stage in water treatment and, for this, jar tests are performed, which allows determining the optimal coagulant and alkalizer doses in coagulation process. However, these tests are time-consuming and do not enable real-time responses to changes in raw water quality. To overcome these limitations, artificial multilayer perceptron neural networks were built, trained, validated and tested to predict the aluminum and sodium hydroxide doses - used as coagulant and alkalizer, respectively. The results of these models are encouraging to consider that the estimated uncertainties have the same order of the variation limits magnitude indicated by the jar tests for almost a six-year period.

Resíduos da construção civil em Salvador: os caminhos para uma gestão sustentável / Construction waste in Salvador: ways to a sustainable management

O artigo discute o impacto ambiental provocado pela geração crescente de resíduos da construção civil e sua disposição inadequada, analisando a legislação sobre o tema e as possibilidades de sua minimização na cidade do Salvador. Como contribuição, são sugeridas medidas para viabilizar a prevenção da geração de resíduos e é proposto um modelo simplificado de fluxo dos resíduos da construção civil em Salvador, para estimular a redução do desperdício nas obras e, conseqüentemente, menor custo na gestão da cidade e menor impacto ambiental. A partir dessa proposta se obteria uma redução da geração dos RCC de 30 por cento, um desvio do aterro de inertes de 37,3 por cento e, ainda, permaneceria seguindo, diretamente, para o aterro 32,7 por cento dos resíduos totais, não absorvidos na reciclagem ou reutilização.