Treatment and reuse of greywater for non-potable applications especially in scarce countries is a feasible option. In this study, a simple greywater treatment system consisting of a low-cost simple multi-media filter with biological contact aeration system was developed and installed in a selected household in Muscat, the capital of Oman. Monitoring and measurements were made to investigate the productivity and efficiency of this system in treating the greywater from laundry and shower sources. The greywater from the collected laundry and shower contained 360 mg/L of COD and 28.5 mg/L of BOD. The experimental results showed that the greywater treatment unit achieved more than 99% of turbidity removal, more than 74% of BOD removal, and more than 50% of COD removal. BOD removal was primarily achieved through bacterial degradation whereas COD removal was attributed to the adsorption of organic compounds by activated carbon. The effluent quality of the treated greywater fell within the standard level and can be safely reused for various non-potable applications.
Water shortage is rising to become a global challenge due to the variations in climate change and population increment. Converting the seawater to potable water using the desalination technology is among the existing options highlighted by researchers. However, these processes are expensive and require much energy to operate. The solar desalination technology was reported as highly adequate since it utilizes the natural sunlight and the simple concepts of evaporation and condensation to produce the drinking water. The main challenge to date is the low productivity of the technology, which must be adequately improved in order to enhance productivity and optimize performance. In this study, the productivity and efficiency of conventional double slope solar still were assessed using a solar system. Two solar still models (active and passive) were fabricated with the same evaporation and condensation areas. The troughs were made of stainless steel with dimensions of 50×32 ×5 cm. In turn, while the cover was made of glass with dimensions of 48×60×0.3 cm and the inclination angle was 60°. In addition, the solar system consisted of two solar panels with 50 W capacity each, one battery of 100 Ah – 12 V, a charging controller of 30 A, and a single immersed DC water heater of 50 W – 12 V capacity. Both models were tested simultaneously for two sunny days, 24 hours each. The results showed that the water productivity of the active solar still was 55% higher than that of the passive solar still. On 15th July, the total amounts of solar still productivity were 7.85 L/m2/d and 19.3 L/m2/d for active and passive stills, respectively. This is due to the existence of the heating element in the active still which allowed it to produce water for 24 hours continuously. Moreover, the trough temperature was found to be the highest for both models, because it was made from steel. Finally, the produced water in both cases was found to be directly proportional to such parameters as solar radiation intensity and ambient temperature.
Among the key challenges of the 21st century, one can enumerate finding efficient technologies to enhance water purification. Seawater desalination had been identified as one of the main alternative solutions to increase the water resources on our planet and fulfill human demands. In this study, the yield performance of double slope solar still connected with the external spiral copper pipe as the water heater was investigated. Active and passive solar stills of equal evaporation area with covers (4 mm thickness and 45° slope in both sides) were manufactured using Perspex. Different parameters were investigated and compared during the experiment including yield and water quality indicators from both stills. The results showed a strong relationship between the water production rates and solar radiation intensities, water temperature as well as ambient temperature. Additionally, the water productivity from the active still was 20% higher compared to the passive one. Overall, the water quality parameters were within the acceptable limits, the rate of distillate water production was found to increase along with solar radiation intensity and water temperature.
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