Kinetics of Nitrification and Denitrification in Hyporheic Zone Sediment with Periodical Supply of Nitrogen
The most significant feature of the river hyporheic zone is the dynamic change of water chemical composition caused by the periodical alternation of river water and groundwater,and the interval between periods is different.The hyporheic zone is a denitrification hot zone,and the response law of nitrification and denitrifying microorganisms to this periodical change determines the nitrogen removal efficiency of the hyporheic zone.According to this,different nitrogen,DO,etc.were supplied multiple times at different intervals to study the kinetics of nitrification and denitrification in multiple cycles.The nitrification and denitrification rates in the first cycle were slow,and there was an obvious hysteresis period.In the subsequent second and third cycles,regardless of the length of substrate dosing interval,no significant hysteresis period was observed for nitrification and denitrification,the reaction rate was accelerated,and the number of functional bacteria increased,but the number of functional bacteria was inversely proportional to the interval time.The initial concentration of nitrate nitrogen significantly affects the nitrous nitrogen kinetic process.The increase in the number of nitrifying and denitrifying bacteria and the maintenance of high reactivity for a long time are one of the efficient nitrogen removal mechanisms in the hyporheic zone.
periodical supply of nitrogenhyporheic zone sedimentnitrificationdenitrificationkineticsgeochemistry
万方数据
维普
