某污水处理厂旋流沉砂池结构改造及运行效果分析

沉砂池是污水处理厂预处理单元重要设备，近年来，旋流沉砂池在市政污水处理厂的应用越来越广泛，但实际运行中存在出砂效果不佳等问题。重点分析了某污水处理厂旋流沉砂池运行效果差、不出砂等问题，提出了换用螺旋曲面桨叶、降低旋桨转速、调整桨叶与底部距离等具体措施。改造后对该厂旋流沉砂池进行连续检测，发现其SS平均去除率由1.86%提升至21.38%，平均出砂量为51 kg/d，同时对COD的截留效果得到一定改善，有利于降低后续生物段的碳源投加量。改造前后沉砂池对TN的去除率基本保持在0.9%左右，而TP平均去除率从0.44%提升至0.99%。总体来说，旋流沉砂池经过改造后运行稳定，除砂效果良好，污水处理厂出水水质得到明显提升。

STRUCTURE MODIFICATION AND OPERATION EFFECT ANALYSIS OF VORTEX-TYPE GRIT CHAMBER IN A WASTEWATER TREATMENT PLANT

Grit chamber is an important equipment of pretreatment unit in wastewater treatment plant. In recent years, vortex-type grit chamber had been widely used in municipal wastewater treatment plant, however the inorganic particles yield was poor in practical operation. This article focused on the the poor operation effect and low inorganic particles yield in a vortex-type grit chamber from wastewater treatment plant. Specific measures including changing to a spiral curved blade, reducing the speed of the blade, and adjusting the distance between the blade and the bottom were proposed. After the modification, continuous testing was conducted on the vortex-type grit chamber of the plant, and it was found that the SS removal rate was significantly improved from 1.86% to 21.38%, with an average sand output of 51 kg/d. Meanwhile, the interception effect of COD was improved, which was conducive to reduce the carbon source addition into the subsequent biological tanks. Compared to the original chamber, the TN removal rate kept at a level of 0.9%, but TP removal rate was increased from 0.44% to 0.99%. In general, the vortex-type grit chamber was more stable and the inorganic particles yield was enhanced after the modification.