Resumo: O fornecimento de água potável é o maior desafio das comunidades rurais da região semiárida do Brasil, que são caracterizadas pela escassez de recursos hídricos apropriados para consumo humano. Em uma tendência observada há alguns anos, os Governos Federal e Estadual têm buscado instalar equipamentos de dessalinização das águas salobras subterrâneas para a geração de água doce para o abastecimento de comunidades distantes dos centros urbanos. Desta forma, o objetivo deste trabalho foi avaliar a qualidade das águas oriundas do processo de dessalinização de poços em comunidades rurais do oeste potiguar e seus riscos quanto ao uso na irrigação. A pesquisa foi realizada no período de 2013 e 2014 e, inicialmente, foram identificadas as comunidades abastecidas com as unidades de captação e tratamento de água por dessalinização, através de um levantamento cadastral. Para isto, foram realizadas quatro campanhas de coletas em diferentes períodos do ano para avaliação da qualidade das águas potável do tratamento por osmose reversa, poço e rejeito salino, dentro de cada período. Foram analisados parâmetros físico-químicos das águas para fins de irrigação. As águas foram classificadas quanto ao uso na irrigação; aos riscos de problemas de infiltração no solo causados pela sodicidade da água e toxicidade em plantas. As estações de tratamento de água por osmose reversa nas comunidades rurais monitoradas produziram uma água dessalinizada com concentrações baixas de sais, com 68% do total das amostras na classe de classificação C1S1; 25% na classe C2S1 e; apenas 7% na classe C3S1. Com relação ao rejeito gerado, 93% das amostras de água de rejeito se classificaram como C3 ou C4 nos quatro períodos de coleta, ou seja, águas de alto ou extremamente alto risco de salinização.. Palavras-chave: Salinidade. Osmose reversa. Água residuária. Abstract:The supply of drinking water is the biggest challenge of rural communities in semiarid region of Brazil, which are characterized by the scarcity of water resources suitable for human consumption. A trend a few years ago, the federal and state governments have sought to install desalination equipment of underground brackish water to generate fresh water to supply more distant communities from urban centers. Thus, the objective of this study was to evaluate the quality of water wells desalination process in rural communities from Potiguar West. This research was conducted between 2013 and 2014. At first, the communities which were supplied by catchment and treatment of desalinated water centers were registered through a cadastral survey. In order to do so, four data collection expeditions took place in different periods as well as the evaluation of a) the reverse osmosis treated water quality, b) the well, c) the reject brine Physicochemical attributes of water for irrigation was also analyzed. The waters were classified according to its use for irrigation; leakage risks and toxicity in plants In the monitored rural communities, the reversed osmosis water treatment stations produce de...

In Mossoró-RN, which is part of the semi-arid region of Brazil, a large part of the country’s melon production is concentrated, whose great potential is currently limited by water quality due to salt concentration. Therefore, the objective of this work was to investigate the use of saline nutritive solutions in the irrigation of greenhouse melon (Cucumis melo L. cv. Néctar) culture in coconut fiber. The experiment was carried out using a randomized block design with a 5 x 2 factorial arrangement, with four replications, where the treatments consisted of nutritivesolutions with five salinity levels (1.25 - control, 1.43, 1.86; 2.96 and 4.86 dS m-1) and for two different times to evaluate fruit quality parameters (at harvest and after 12 days of storage). Increasing the salinity in the nutrient solution reduces fruits’ mean weight, while total yield is only reduced with EC above 3.5 dS m-1. Fruit length anddiameter and peel and pulp thickness, SS and pH, decrease when submitted to nutrient solution with EC above 3.8 dS m-1. The peel and pulp thickness, pulp internal cavity, firmness, SS, pH, TA and fruit SS/TA ratio were influenced by the storage period.

A B S T R A C TThe objective of this work was to evaluate changes in the chemical attributes of an Inceptisol in two areas of sustainable management of the Caatinga Biome and a conventional tillage, compared with the native forest. The areas were managed in the following way: in areas under sustainable management, the Caatinga was thinned in a savanna system (1), and in the other area, the Caatinga was thinned in strips (2); the area under conventional tillage was burned, plowed and harrowed (3), and the native forest (4). The following chemical attributes were analyzed: pH, electrical conductivity, Ca 2+ , Mg 2+, H + Al, P, Na + , K + and soil organic matter (SOM), calculating CEC and base saturation. The treatments were evaluated using multivariate analysis, at different depths up to 0.52 m. In the Caatinga areas thinned in a savanna system and in strips, the greater availability of exchangeable bases and SOM occurs close to the depth of 0.20 m and, in the area with traditional agriculture, it is limited to 0.10 m. In the area thinned in a savanna system, sodium showed a negative correlation with the other elements.Atributos químicos em área agrícola tradicional e Caatinga manejada em diferentes profundidades em um Cambissolo R E S U M O Objetivou-se, neste trabalho, avaliar mudanças nos atributos químicos de um Cambissolo háplico em duas áreas de manejo sustentável da caatinga e em uma área de cultivo agrícola convencional e se optou, para efeito de comparação, pela mata nativa (Caatinga). As áreas foram manejadas da seguinte forma: Nas áreas em que houve manejo sustentável foi feito raleamento na caatinga com sistema de savana (1) e na outra área raleamento em faixas (2); na área de cultivo agrícola convencional foram realizadas queimada, aração e gradagem (3) e a mata nativa (4). Os atributos químicos analisados foram: pH, condutividade elétrica, Ca 2+ , Mg 2+, H + Al, P, Na + , K + e matéria orgânica do solo (MOS) calculando-se CTC e saturação por bases. Os tratamentos foram avaliados por meio de análises multivariadas, em várias profundidades até 0,52 m. Verificou-se que na área de caatinga raleada em savana e em faixa, houve maior disponibilidade de bases trocáveis e MOS próximos aos 0,20 m de profundidade e na área com agricultura tradicional se restringe a 0,10 m. Na área raleada com sistema de savana o Na apresentou correlação negativa com os demais elementos indicando situação de antagonismo.

Brazilian semi-arid productive techniques use rainwater harvesting systems, which are a sustainable water management practice with a low environmental impact that have been adopted as an alternative to meet water demand worldwide. The aim of this study was to find an optimal sizing methodology for rainwater harvesting systems using local parameters allied to the lowest system cost. The analyses were based on a system supplying 95% of a 250 L/d demand for a goat herd in Feira de Santana, Bahia, Brazil. The area available for system implementation did not limit the analysis. The only limiting parameters were the quantity and quality of water required for the herd. The results indicated that, among the combinations of catchment area and water tank volume capable of meeting the defined demand, there is an optimal set, with minimum cost. This was a catchment covering 220 m² with a 21.1 m³ water tank, equivalent to a 0.62 demand fraction (FD). The variance influence of meeting service efficiency and demand, in the system's implementation and performance, was also analyzed.

Reverse osmosis is the technology commonly used to produce fresh water from brackish groundwater. Due to the reject brine generated in desalination plants by reverse osmosis, vulnerability assessment to define critical areas to monitor waters from desalination has been an important tool for delineating the monitoring networks required for surveillance of potential salinization sites. The objective of this study was to assess the quality of waters sampled in desalination plants by a quality index, which provides a relative assessment of water vulnerability to potential salinization. The present study proposes an index to assess the quality of waters from desalination plants initially using the chemical parameters electrical conductivity, sodium adsorption ratio, Mg2+/Ca2+ ratio, and the ions sodium, chloride and bicarbonate. The index to assess quality of waters from desalination plants showed good performance and can include additional parameters referring to the soil and crop exploited. High values of the relative index of quality of waters from desalination plants are considered as possible indicators of risk of soil salinization and groundwater contamination. The highest level of land use impact on the quality of waters from desalination plants was found in reject brine samples followed by well water samples.