不同流速下溢流堰对河道水质的影响

摘要

The influence of stepped dam with 45-degree slant angle to the river water quality was studied under the different velocities and the wa-ter nutrient and organic contamination at the dam crest and the dam toe were monitored under the different velocities. The results show that the aera-tion degree is significantly different after the flow crossing the stepped dam under the different velocities. The effect of the medium current velocity (about 125. 00 cm/s)is the best and the increasing rate of the dissolved oxygen is the maximum. The contents of permanganate index,ammonia nitrogen,total nitrogen and total phosphorus are decreased after the stepped spillway and the removal effect is the maximum under the medium cur-rent velocity. The removal rate of the total phosphorus content is the maximum under the low current velocity. Due to the shorter overflow weir dis-tance,the improved effect of part of water quality indexes is not significant.%通过对不同流速条件下水体经过45°阶梯式溢流堰坝体后水体营养盐及有机污染物指标的定期监测和分析，探讨阶梯式溢流堰在何种水动力条件下对水体的改善作用最大。结果表明：水体经过溢流堰曝气作用后，不同流速条件下其复氧程度不同，中流速（125．00 cm／s）条件下效果最佳，DO增加率最大；水体经过45°阶梯式溢流堰曝气作用后，IMn、NH3－N、TN、TP含量均降低，其中IMn、NH3-N、TN在中流速条件下去除效果最佳，而TP去除率在低流速条件下最大；由于溢流堰距离较短，因此部分水质指标改善效果不显著。