Trial Study on Designing of Sand-Settling Tank for Runoff Harvesting

Through contrast study on the sand sinking rate of 4 kinds of setting tanks, the results show that labyrinth style settling tank is the best among single echelon settling tank, single square shape settling tank, and rotary setting tank. The labyrinth tank can settle 88.3% of sand. The form of labyrinth tank with a 1×0.4 m² scale and with 5 intersection dams. The distance between intersection dams is 0.146 cm. Every dam has a 0.2×0.2 m² hole for waterway. The first intersection dam has built a 0.25 m deeper settling basin with which sand can be easily catched in tank.