摘要
以某再生水厂曝气沉砂池为研究对象,分析进水颗粒物组分和粒径分布等特性,设计并运行曝气沉砂池中试模型装置,研究了水力停留时间、气水比、曝气量分布和预曝气等工艺条件对沉砂池除砂效果的影响。曝气沉砂池进水砂砾中大颗粒物较少,主要为细小颗粒物,粒径在0.076 mm以下的颗粒物为进水主要成分;进水颗粒中有机物所占比例较高,VSS/SS平均达到67.5%。水力停留时间的延长有利于提高沉砂效果;5、10 min和20 min三种水力停留时间条件下的总颗粒物去除率分别为11.5%、31.6%和48.8%。适量的曝气有利于颗粒物的去除,但过量曝气会影响整体去除效果。气水比为0.05、0.1和0.2三种条件下的总颗粒物去除效率分别为33.52%、23.02%和19.19%。曝气量分布对除砂效果有较大影响,相比均匀曝气和前弱后强两种曝气方式,在前强后弱的曝气方式下,沉砂池具有较好的去除效果,总颗粒物去除率为41.23%。通过设立隔板及预曝气,可提高有效沉淀时间,有利于提高曝气沉砂池的去除效果;在仅曝气区曝气、预曝气/曝气区曝气和仅预曝气三种条件下,仅进行预曝气时工艺具有较高总颗粒物去除率,为46.79%。
One reclaimed treatment plant was selected to investigate the factors affecting operating performance of the aerated grit chamber. Components and size distribution of influent particles were studied. A pilot scale aerated grit chamber was designed and operated to clarify the effect of hydraulic retention time （HRT）, aeration density, aeration distribution and pre-aeration on the particles removal performance. There were more particles with a small particle size than that with a large particle size in inflow and the particles with a size smaller than 0.076 mm was the dominant component in influent particles. A high proportion of organic matters was observed in influent particles, with a VSS/SS ratio of 67.5%. Particles removal could be improved by extending the HRT. Under HRT of 5,10 min and 20 min, the grits removal efficiency in system was 11.5%, 31.6% and 48.8%, respectively. An appropriate aeration density had positive effects on particles removal while an excessive aeration had a negative effect. Under air to water ratio of 0.05, 0.1 and 0.2, the particles removal efficiency was 33.52%, 23.02% and 19.19%, respectively. Aeration distribution had large impact on particles removal, under three aeration strategies, namely equality aeration rate, low aeration intensity/high intensity and high aeration intensity/low aeration intensity, a high removal efficiency of 41.23% was achieved under the high aeration intensity/low aeration intensity strategy. By pre-aeration and setting a dam board after pre-aeration area, particles removal efficiency increased because of an extension of effective settling time. The removal efficiency was 46.79% with only pre-aeration in the system, which was much higher than that with pre-aeration/normal aeration and only normal aeration.
出处
《净水技术》
CAS
2017年第8期13-19,31,共8页
Water Purification Technology
关键词
曝气沉砂池
粒径分布
水力停留时间
曝气强度
除砂效果
aerated grit chamber particle size distribution hydraulic retention time （HRT） aeration intensity sandremoval efficiency
