喀斯特地区污水含砂特征及除砂工艺优化研究

Study on characteristics of wastewater grit content and grit removal process optimization in Karst Area

为明确我国喀斯特地区的污水含砂特征,指导该区域除砂工艺的设计与运行,选取位于喀斯特典型城市贵阳市的三座污水处理厂针对性地开展相关试验。结果表明:试验地区污水含砂特征主要受喀斯特地貌、排水体制、降雨及土壤侵蚀等因素影响,具体表现为旱季进水含砂量高,雨季进水含砂量增幅高且粗砂含量高,砂有机物含量偏低。该区域曝气沉砂池各参数最佳范围分别为气水比0.1~0.15、单位池长曝气量1.5~3.0 L/(m·s)、水力停留时间10~15 min。喀斯特地区曝气沉砂池应向着延长水力停留时间、降低气水比的方向定制化设计。此外,曝气量的设计宜参照单位池长曝气量,实际运行宜参照气水比。

In order to clarify the grit characteristics of wastewater in karst area in China and guide the design and operation of desanding process in this area,three wastewater treatment plants located in Guiyang,a typical Karst City,were selected to carry out relevant tests.The results show that:the characteristics of wastewater grit content in research area are mainly affected by karst landform,drainage system,rainfall and soil erosion,which shows that the grit content of influent in dry season is high,the increase of grit content in rainy season is high and the content of coarse grit is high,and the organic matter content of grit is low.The optimal range of gas-water-ratio of aeration grit chamber in karst area is 0.1~0.15,the optimal range of aeration per unit tank length is 1.5~3.0 L/(m·s),and the optimal range of hydraulic retention time is 10~15 min.The design of aerated grit chamber in karst areas should be customized to extend the hydraulic retention time and reduce the gas water ratio.In addition,the design of aeration volume should refer to the aeration volume per unit tank length,and the actual operation should refer to the gas water ratio.