营造光照环境控制污水管道中有害气体的研究

Control of Harmful Gas in Sewage Pipeline through Creating Light Environment

预防管道腐蚀和安全事故的发生是排水系统提质增效的重要方向,而管道通风不畅及黑暗环境中产生的硫化氢(H2S)和一氧化碳(CO)等有害气体是事故发生的主要诱因。针对管道内有害气体产生的问题,提出了在管道内营造近污水明渠输送环境控制有害气体产生的新方法,建立了模拟污水管道实验模型,探究了管道内增加光照对有害气体的控制效果及对污水水质的影响。结果表明,与黑暗环境的污水管道相比,增加光照可使H2S气体浓度降低47.2%、硫化物浓度降低36.7%、CO浓度降低59.8%,可有效抑制管道内有害气体的产生;同时COD和TN浓度分别可降低12.0%和5.0%,污水碳氮比变化较小;生物膜镜检发现,增加光照改变了管道内的微生物群落,促进了管道内藻类的生长,形成菌藻聚生体;分析表明,藻类生长释放氧气,改变管道内的厌氧环境,抑制产气厌氧菌是营造光照环境控制有害气体的主要作用机制。营造光照环境可为控制污水管道中的有害气体提供技术选择,为城市排水系统规划和建设提供新思路。

Prevention of pipeline corrosion and safety accident is an important direction to improve the quality and efficiency of drainage system,and harmful gases such as hydrogen sulfide(H2S)and carbon monoxide(CO)produced in pipelines with poor ventilation and dark environment are the main causes of accidents.Aiming at the problem of harmful gases generation in sewage pipelines,a new method to control harmful gas generation by creating similar open sewer transport environment in sewage pipelines was proposed,and an experimental model of simulated sewage pipelines was established to investigate the effect of light on harmful gas control and sewage quality.Compared with sewage pipelines in dark environment,concentrations of H2S,sulfide and CO were reduced by 47.2%,36.7%and 59.8%by illumination,indicating that the generation of harmful gas was effectively inhibited in the pipelines.Meanwhile,concentrations of COD and TN decreased by 12.0%and 5.0%,respectively,and the carbon to nitrogen ratio of sewage did not change significantly.Biofilm microscopy indicated that illumination altered the microbial community and promoted the growth of algae to form bacterial-algal aggregates in the pipelines.Algae growth would release oxygen,change the anaerobic environment and inhibit aerogenic anaerobes in the pipelines,which was the main mechanism of controlling harmful gas generation by illumination.The light environment can provide technical choice for controlling harmful gas in sewage pipelines and new ideas for urban drainage system planning and construction.