Sludge toxicity assessment of water and sewage treatment plant before and after vermicomposting, using germination test with lettuce seed (Lactuca sativa)

The objective of this work was to evaluate the phytotoxicity of elutriate obtained from WTP and WWTP sludge before and after treatment by vermicomposting (TVC). The tests used the interfacial water of pure and consorted sludge in the 75, 50 and 25% of the respective sludge (mixture of WTP and WWTP sludge) sludges. To evaluate the toxicity were used seeds of lettuce, Lactuca sativa. The lettuce seeds were placed in Petri dishes with filter paper and moistened with 4 mL of elutriate solution, the plates were sealed with plastic film, to avoid evaporation of the elutriate, and later with aluminum foil, to preserve the absence of light, kept in a BOD type incubator at 25 ± 1 ºC for 120 hours. The design was completely randomized with 15 samples of each sludge mixture, before and 15 after the TVC, 5 dilutions (10, 25, 50, 75 and 100%) and three replications, totaling 450 sample plots and 6 plots of controls. Al concentrations were determined in all samples and controls. The toxicity test showed that there was an increase in germination index after CVT; As well as the elutriatro, with the highest dilution of 10% and lower Al concentration, obtained a more expressive result, showing that the germination of the seeds was reduced proportionally to the increase of aluminum concentrations present in the elutriate.Objetivou-se com este trabalho avaliar a fitotoxicidade de elutriato obtido a partir do lodo de ETA e ETE antes e após o tratamento por vermicompostagem (TVC). Os ensaios utilizaram a água interfacial de lodos puros e consorciados nas parcelas de 75, 50 e 25% dos respectivos lodos (mistura dos lodos de ETA e ETE). Para a avaliação da toxicidade foram utilizadas sementes de alface, Lactuca sativa. As sementes foram colocadas em placas de Petri com papel de filtro e umedecidas com 4 mL de solução de elutriato; as placas foram vedadas com papel de filme plástico, para evitar a evaporação do elutriato, e posteriormente com papel alumínio, para preservar a ausência de luz, sendo mantidas numa incubadora, do tipo DBO5 a 25±1 ºC por 120 h. O delineamento foi inteiramente casualizado, com 15 amostras de cada mistura de lodo antes e 15 após o Tratamento por Vermicompostagem (TVC), 5 diluições (10, 25, 50, 75 e 100%) e três repetições, totalizando 450 parcelas de amostras e 6 parcelas de controles. Em todas as amostras e nos controles foram determinadas as concentrações de Al. O teste de toxicidade mostrou que houve um aumento no índice de germinação após TVC; assim como o elutriato com a maior diluição de 10% e menor concentração de Al, obtiveram-se resultados mais expressivos, mostrando que a germinação das sementes foi reduzida proporcionalmente ao aumento nas concentrações de Al presente no elutriato.info:eu-repo/semantics/publishedVersio

Influence of Extreme Strength in Water Quality of the Jucazinho Reservoir, Northeastern Brazil, PE

The Jucazinho reservoir was built in the State of Pernambuco, Northeastern Brazil, to water supply in a great part of the population that live in the semi-arid of Pernambuco. This reservoir controls the high part of Capibaribe river basin, area affected several actions that can compromise the reservoir water quality such as disposal of domestic sewage, industrial wastewater and agriculture with use of fertilizers. This study aimed to identify the factors that lead to water quality of the Jucazinho reservoir using a database containing information of nine years of reservoir water quality monitoring in line with a multivariate statistical technique known as Principal Component Analysis (PCA). To use this technique, it was selected two components which determine the quality of the reservoir water. The first principal component, ranging from an annual basis, explained the relationship between the development of cyanobacteria, the concentration of dissolved solids and electrical conductivity, comparing it with the variation in the dam volume, total phosphorus levels and turbidity. The second principal component, ranging from a mensal basis, explained the photosynthetic activity performed by cyanobacteria confronting with the variation in the dam volume. It observed the relationship between water quality parameters with rainfall, featuring an annual and seasonal pattern that can be used as reference to behaviour studies of this reservoir