Experimental Study on Blockage Law of Constructed Rapid Infiltration System

A laboratory experiment of constructed rapid infiltration system that constructed by 3 types grain size of filler composed of natural sands was performed to investigate the blockage law and recovery of the treatment system. The relationship between the grain size of filler and the drainage quality, the hydraulic loading and the pollutants capacity of the system was studied under the specific wet/dry ratio condition (3 hours to 3 hours), as well as the influence of environmental temperature on the treatment efficiency. Results indicated that stop running some days to fully oxygen-rich when the constructed rapid infiltration system became blockage, then the system could be recovery natural. The system constructed by fine sands of grain size ranging from 0.9 millimeter to 2.0 millimeter had best stability, the drainage quality was most stable, and the resistant ability and the pollutants capacity was stronger than those system constructed by mixing sands and coarse sands. When the environmental temperature fluctuated in the range of suitable for microbial growth, the influence on the treatment efficiency of the system was not obviously, but it had some influence on the natural recovery of the system. The actual project of constructed rapid infiltration system should be built as multi-level systems or parallel systems to solve blockage, which is useful for ensuring the hydraulic loading and the running stability of the system.