Managing water wastage, wasting time and increasing the efficiency of the filters using tube settlers

The Isfahan water treatment plant, with a final capacity of 12.5 cubic meters per second, is one of the largest water treatment plants in the Middle East. It has 10 sedimentation basins with a retention time ranging from 1.91 to 2.75 hours; each basin has a volume of 9172 cubic meters and a surface load of 14.2 to 2.85 cubic meters per square meter per hour. This research was conducted to investigate the efficiency of the combined use of accelerator sedimentation basins equipped with tube settlers on a full and field scale. The goal was to achieve greater efficiency in improving the quality of output water and managing the reduction of water wastage, backwashing time wastage, as well as reducing the need for repairs and maintenance of treatment plant equipment. In this study, the accelerator sedimentation ponds related to two stream 1 clarifiers from the first phase of the treatment plant were equipped with rapid tubular settlers made of food-grade polypropylene. These settlers are hexagonal in shape with a hydraulic diameter of 50 to 80 mm; placed at a 60-degree angle to the surface, and have a length of 90 cm. Stream 2 was operated without the simultaneous use of rapid tube settlers in the circuit. The amount of backwashing’s of filters, the number of times the aerators and backwashing pumps are engaged in the circuit, the amount of water wastage, and the time required for each wash in streams 1 and 2 were compared with each other. The results of this study showed that the number of times of reverse washing of filters was reduced by an average of 25% compared to stream 2. This action also reduced the amount of water used for backwashing the filters and consequently reduced the number of working hours of the electrical and mechanical equipment of the water treatment plant.