Interaction effect of micro- and macro-organic on the biogeochemical function of the sediment and aquatic interface

Constructed stormwater infiltration basins have been broad applied in urban areas in terms of stormwater disposal and compensation of reduced groundwa ter recharge. However, stormwater derived from sediments accumulating in infilt ration beds may act as a source of dissolved contaminants for groundwater. Conce ntrations of DO, NO3--N, NO2--N, NH4 -N and PO43--P were monitored at multiple d epth with time. The results showed that the occurrence of denitrificarion was re strained by sediments in term of no invertebrates. Under the conditions of inver tebrates inoculated, the concentrations of DO, NO3--N, NO2--N, NH4 -N and PO43-- P varied respectively with time and the occurrence of nitrification and mobilizi ng nitrate in the sediment. It is concluded that there exist the invertebrate ac tivities such as building tubes and galleries and excreting faecal pellet which may increase water dispersion and enhance accessibility of nutrient, and stimul ate microbial process effected in the sediment. Besides, the natural death and r ot of worms were also found to be important factors of the invertebrate activiti es.