Development of a complete and straightforward hybrid model for gray water treatment

Abstract

One of the most essential methods for preserving water resources is water reuse. The present study has been aimed at adjusting a gray water treatment system with high purification efficiency, low cost, easy maintenance, and high availability in every environment. To this goal, a new simple hybrid model for gray water treatment was made. In this model after conducting the settlement and aeration processes, seven different combinations of polypropylene activated carbon and anthracite filters beside resins were utilized for removing the contaminants in single and combined forms with three repetitions, and the results of each step were compared with the available standards. The different flow rates of 5, 2, 1, 0.5, 0.25, and 0.1 l/min were passed through the selected system to assess their effects on the reduction efficiencies of the pollutants in the system. The instantaneous ozonation method was used at the ozone concentrations of 1, 2.5, and 5 g/h. The results suggested the weakness of each filter alone for reducing the pollutants. After investigating the seven combinations, the combined filter of “polypropylene + resin + activated carbon” was recognized as the best filter for nondrinking purposes. The pH accounted for the lowest change of 10%, and chlorine and BOD5 accounted for the highest omissions of 90% and 80%, respectively. The system displayed the best performance at the flow intensity of 0.25 l/min or 15 l/h. The minimum rate of ozone production 1 g/h was able to remove all the coliform within any periods. This treated gray water is suitable for nondrinking uses such as irrigation and washing places.