Nature Environment and Pollution Technology (Mar 2022)
The Effects of Disturbance on the Release of Nitrogen and Phosphorus from Sediment in Rural Ditches
Abstract
Reduced nitrogen (N) and phosphorus (P) released from sediments in rural areas pose a significant challenge to residential sewage treatment and management. Under different disturbance velocities, simulation experiments were undertaken to investigate the effect of disturbance on the release of N and P from rural ditch sediments into the water at the water-sediment interface. No significant difference in the release characteristics of N and P was found among different disturbance velocities. The release fluxes of TN and NH4+-N in the non-disturbance water body were significantly higher than in the disturbance water body, which suggests that increasing water flow influences the release of TN and NH4+-N from sediment into the water. The release fluxes of TP and PO43--P were significantly lower in non-disturbance than the disturbance water body, which suggested that disturbance increased the release of TP and PO43--P in sediments. For both disturbance and non-disturbance conditions, TN and NH4+-N in the sediment were rapidly released into the water body at 0-10 days, and TP and PO43--P steadily rose in the disturbance water body until stabilizing after 20 days. TN, NH4+-N, TP, and PO43--P concentrations all had a negative correlation with DO, and the correlations between TN and NH4+-N were substantial. The percentages of a certain N or P speciation fraction in sediments did not alter between disturbance and non-disturbance conditions, implying that disturbance had no effect on N or P speciation.
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