A simplified method to calculate the percentage of fresh effluents (PFE) in non-steady state reactors

Storage reservoirs are a key element in wastewater treatment trains for agricultural reuse; however, there is a need for further research on design criteria and operation rules for such reactors. The percentage of fresh effluents (PFE) is an important parameter for the design of perfectly-mixed reactors. PFE correlates better than mean residence time with the performance of the reactor. It allows for estimation of the removal of pollutants in non steady-state systems, such as seasonal wastewater storage reservoirs, and for forecasting the quality of the effluents released for irrigation. However, calculation of PFE is a difficult process requiring complex computer algorithms. A simplified analytical approach is developed to calculate the PFE for n days. The formulation is discussed, describing the relationships between the hydraulic variables, and then applied to a non-steady-state continuous-flow wastewater reservoir in Eastern Sicily (Italy). Keywords: hydraulic age distribution, perfectly-mixed reactor, mean residence time, wastewater storage reservoir

Avances en la elaboración de un sistema termosolar inteligente de descarga pulsada

Se presenta la elaboración y evaluación de un prototipo termosolar de descarga pulsada programable. El mismo se basa en un sistema electrónico inteligente, adquisidor y de control, que decide las estrategias de descarga del agua caliente que se genera en un absorbedor construido con una larga manguera negra de polietileno. Las descargas se realizan hacia un tanque aislado al momento en que la temperatura del agua en el absorbedor llega a cierto valor determinado. Este controlador es diseñado de tal manera de poder programar las estrategias que maximicen la eficiencia y/o la producción total de agua caliente en distintas condiciones ambientales. Según la simulación térmica-solar presentada en otro trabajo, se espera que este sistema pueda producir grandes cantidades de agua caliente a un muy bajo costo, y satisfacer demandas tanto residenciales como industriales.We present the first steps in the development and evaluation of a solar thermal prototype of pulsed discharge. It is based on an intelligent digital electronic controller, which decides the strategies of discharge of the hot water generated in an absorber constructed of a long black polyethylene hose.The discharges are led to an insulated tank when the water temperature in the absorber reaches a certain predetermined value. This electronic controller is designed to program strategies to maximize the hot water production efficiency in different environmental conditions. The system may, at a very low cost, produce large cuantities of hot water, and meet the demand, both residential and industrial.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Crescimento e produtividade da mamoneira irrigada com diferentes diluições de esgoto doméstico tratado Growth and production of castor bean irrigated with different dilutions of domestic wastewater

Objetivou-se avaliar, neste trabalho, os efeitos da irrigação com água de esgoto doméstico sobre as variáveis de crescimento e produtividade da mamoneira, genótipo EBDA MPB 01, em condições de campo. A pesquisa foi realizada no período de dezembro de 2009 a junho 2010, na Universidade Federal do Recôncavo da Bahia, Campus de Cruz das Almas. Foram estudadas quatro diferentes proporções de diluição de esgoto doméstico tratado em comparação com o tratamento testemunha (adubação e irrigação convencional), da seguinte forma: T1 - 100% do efluente tratado; T2 - 75% do efluente tratado mais 25% de água de poço artesiano; T3 - 50% do efluente tratado mais 50% de água de poço artesiano; T4 - 25% do efluente tratado mais 75% de água de poço artesiano e T5 - manejo convencional (adubação química e irrigação suplementar com água de poço artesiano). O delineamento experimental foi em blocos casualizados (DBC) com quatro blocos cada tratamento, constituindo de 20 parcelas experimentais. A produtividade da mamoneira não apresentou diferença estatística entre os tratamentos. O uso de água residuária de esgoto doméstico na cultura da mamoneira, não afetou as variáveis de crescimento analisadas.<br>The effects of the irrigation with domestic wastewater effluent on the growth variables and the productivity of castor bean, genotyps EBDA MPB 01, were evaluated under field conditions. The research was carried out from December 2009 to June 2010, at UFRB experimental area, in Cruz das Almas, BA. Four different proportions of dilution of domestic wastewater effluent in comparison with the conventional treatment were studied, in the following way: T1 - 100% of the treated effluent; T2 - 75% of the effluent +25% of artesian well water; T3 - 50% of the efluent +50% of artesian well water; T4 - 25% of the effluent +75% of artesian well water; T5 - conventional treatment (chemical fertilization and supplementary irrigation with water of artesian well). A randomized block design was used with four replications, totaling 20 experimental units. The productivity of the castor been did not show statistical differences among the treatments. The use of wastewater in castor been crop did not affect the growth variables analyzed