Study on Winter Flow Constructed Operation Process Wetland in Tianjin of the Surface Area

摘要

[Objective] The research aimed to study winter operation process of the surface flow constructed wetland in Tianjin area.[Method] In view of climate characteristics in Tianjin,by the way of running under the ice,winter operation experiment of the surface flow constructed wetland in Tianjin was conducted,with the expectation to get some useful process parameters to run such systems in North China in winter.[Result] Although purification effect of the sewage by surface flow constructed wetland in winter was worse than that in other seasons(average reduction of about 20%),surface flow constructed wetland running under the ice was feasible in Tianjin area.When surface flow constructed wetland in North China ran under ice in winter,it was suggested that the outlet must be located in a low position to prevent to be completely frozen,and running water depth should not be less than 50-60 cm.The hydraulic load could be raised on the basis of reflux,and hydraulic retention time should maintain less than 4 d to keep water-soil interface not freezing.Inlet water depth should be increased as much as possible to improve temperature in the system.[Conclusion] The research could provide reference for promotion and application of the surface flow constructed wetland in North China.