Revista Ambiente & Água - An Interdisciplinary Journal of Applied Science

1-12

Authors: Igor Felipe Silva Moura; Alberto Avellar Barreto; Raisa Helena Sant’Ana Cesar; Ananda Borjaille Cruz; Maria Ângela de Barros Correia Menezes

Particulate matter is the mixture of solid and liquid particles. It may at times cause adverse effects to human health, in the climate, ecosystem and materials. The objective of this study was to identify the sources emitting particulate matter that contributes to environmental pollution at two sites in Belo Horizonte city. The metropolitan region of Belo Horizonte is characterized by numerous mining activities and other industries, high population and, consequently, a high number of vehicles. There are therefore several sources emitting pollutants into the atmosphere. Airborne particulate matter was collected in air filters during approximately one year using a high-volume sampler in strategic points. The concentration of particulate matter results showed that, in general, the values were 40% higher than the values recommended by legislation. During the summer rainy season, no sample exceeded the recommended limits at both sampling sites. The elemental composition was determined through neutron activation analysis and these values were considered variables in the multivariate statistical analysis for the identification of the main sources of particle emission and their contributions. The results confirmed a significant influence of the soil and motor vehicles in the degradation of the region’s air quality.

1-10

Authors: Fábio Orssatto*; Maria Hermínia Ferreira Tavares; Flávia Manente da Silva; Eduardo Eyng; Leandro Fleck

This work evaluated the removal of total Kjeldahl nitrogen (TKN) and total phosphorus (P) through electrocoagulation and used aluminum electrodes to optimize the potential differential (pd) and hydraulic retention time (HRT) variables in a batch reactor. The experimental design used was Rotatable Central Composite Design (RCCD). The application of the electrocoagulation in the treatment of effluents from pig slaughterhouses and packing plants proved to be efficient in relation to the removal of TKN and total phosphorus, obtaining maximum efficiency equal to 67.15% and 99%, respectively. The maximum TKN removal value was found in Test 12, where treatment conditions were 30 minutes for HRT and 20 volts for pd, which corresponds to 0.86 A of electric current and a current density of 17.2 mA cm-2. For P, the only test that removed below 99% was the first. Through statistical analyses, it was only possible to obtain a mathematical model for TKN removal. While the response surface graph did not present a defined range of the best conditions for the independent variables, it was possible to observe the tendency for better removal, a wide range of pd and values over 30 minutes for retention time.

1-11

Authors: Francesco Lombardi; Guglielmo Silvagni; Piero Sirini; Riccardo Spagnuolo; Fabio Volpi*

This paper develops a model to characterize the demand for domestic water based on its end users' usage habits. The use of individual residential appliances (bathroom sink, toilet, shower, bath, etc.) is interpreted using a probabilistic approach. The paper also applies the model to the distribution network of the municipality of Sparanise, a small city in the province of Caserta, Italy. The results of this application are compared to the real output of the city's actual water reservoir. Flow variability during the day was successfully modelled. A comparison of the simulated and recorded data on a daily level indicates the proper adjustment of the volume distribution; the peak flow rates were also comparable. The model could be a useful tool for analyzing domestic water consumption, especially in the design and management of water distribution networks. Use of the model would particularly aid the Integrated Urban Water Management Operator both in optimizing the operating pressures in the various districts’ networks and in predicting domestic water consumption when drafting its water balance documents.

1-15

Authors: Kalesson Martins Alencar*; Michel Castro Moreira; Demetrius David da Silva

This study analyzed the relative cost of charging for water use with respect to water users' production costs in the Grande River Basin, located in the Brazilian Cerrado, considering the principal charging methods existing in Brazil. The study was developed based on: the rights of use grant data surveys pertaining to water resources and the classification of bodies of water into usage classes; a simulation of charging for water use through various methods; and an analysis of the relative cost of charges on the production cost of the water users. The charging methods used by the following were studied: the Committee of the Basin of River Paraíba do Sul (CEIVAP), the Committee of Basins of Piracicaba, Capivari and Jundiaí Rivers (PCJ), the São Francisco River Basin Committee (CBHSF) and the Doce River Basin Committee (CBH-DOCE). The study verified that irrigated agriculture is the sector that uses the most water, representing 46.4% of the outflow granted in the basin. Considering the different charging methods, the collection in the basin of the Grande River potentially allows for investments of US$ 1.2 million (PCJ), US$ 920,000 (CEIVAP), US$ 426,000 (CBH-DOCE), or US$ 297,000 (CBHSF) in this region, leading to average relative costs of 0.68% (irrigation), 0.28% (human) and 0.08% (industry). For this reason, there is the possibility of implanting charges for water use in the Grande River Basin, with either the CEIVAP's or PCJ's method appearing to be the most suitable, given that the parameters of these mechanisms are in line with existing activities in the basin.

1-21

Authors: Chrystopher Allan Miranda Pereira; Núbia Natália Brito*

This study investigated of the potential value of the integration of the coagulation/flocculation, Advanced Oxidation Processes (AOP) (Fenton reagent) and slow sand filtration technologies, with the aim of treating laboratory wastewater. The treatment system was designed in laboratory scale through coagulation/flocculation. It involved the use of Jar Test equipment with a sequence of two rotational phases: fast mixes to 300 rpm for 20 seconds and slow mixes to 30 rpm for 6 minutes and 10 seconds, with the addition of anionic polymer and sedimentation for 60 minutes at ambient temperature. In the treatment via Fenton reagent, two rotational phases were used: rapid mixing at 300 rpm for 20 seconds with the addition of iron (Fe2+) and slow mixing at 30 rpm for 6 minutes and 10 seconds with the addition of hydrogen peroxide, followed by 60 minutes of sedimentation at ambient temperature. A cylindrical tank of polyvinyl chloride, sands and non-woven synthetic fabrics were used in the slow filtration. The filtration rate adopted was 3 m3 m-2 d-1 with a hydraulic retention time of 264 minutes. The best concentrations of chemical reagents used in the treatments were:0.80 mg L-1 of polymeric anionic, 200.00 mg L-1 of H2O2 and 13.00 mg L-1 of total soluble iron. The integration of the treatment technologies made it possible to achieve a removal rate of 75.27% of COD and 94.12% of total phenols. Furthermore, the conjugation of the processes allowed the removal of 87.58% of TOC.

1-10

Authors: Douglas Cavalcante Costa*; Lucieta Guerreiro Martorano; José Reinaldo da Silva Cabral de Moraes; Leila Sheila Silva Lisboa; Rubismar Stolf

O objetivo neste trabalho foi analisar a dinâmica temporal da pegada hídrica de oito cultivares de soja, plantadas na região do Oeste do Pará. Foram utilizados dados meteorológicos correspondentes ao período de 2009 a 2014 para calcular as taxas evapotranspiratórias da cultura. Como a Pegada Hídrica é subdividida em verde, azul e cinza e, na região os cultivos não são irrigados contabilizou-se apenas a verde e a cinza. A PHverde foi estimada considerando-se o total de água consumida durante o ciclo de cada cultivar. A PHcinza foi avaliada utilizando como fator contaminante em corpos hídricos o composto nitrato que está presente nos fertilizantes nitrogenados, conforme as concentrações aceitáveis pelo CONAMA 357/2005. Considerou-se dois valores para as doses de N, sendo 30 kg ha-1 com base na adubação descrita na literatura, bem como o N existente nas formulações (2:20:20) dos adubos vendidos na região, sendo 2 kg ha-1 o máximo utilizado na adubação de cobertura. Entre as oito cultivares analisadas, em termos de indicador de baixa pegada hídrica, as cultivares BRS 278 RR; BRS 325 RR e BRS 333 RR foram as mais expressivas no polo de grãos no oeste do Pará, evidenciando o uso eficiente da água disponível em todos os anos/safras analisados. A soja produzida no oeste do Pará possui baixa pegada hídrica cinza. Todavia, os valores de redução da produtividade em anos safra na região comprometem a pegada hídrica verde pela sojicultura na região, evidenciando que esse indicador deve ser analisado considerando as especificidades de cada cultivar de soja. O valor da pegada hídrica total estimada neste trabalho foi inferior aos obtidos na literatura, reforçando a importância de estimar a Pegada Hídrica (PH) como indicador de uso consuntivo de água em cultivos de grãos na Amazônia.