Abstract
To investigate the contribution of the treatment stages as well as the effect of vegetation and hydraulic condition on the start-up water purification performance during 8 month operation including winter, a full-scale experimental study was conducted on a 5-stage subsurface vertical flow constructed wetland treating daily milking parlor wastewater and non-periodical paddock run-off. Despite great variation of pollution loading caused by paddock run-off due to seasonal rainfall, efficient removal was attained for BOD, suspended solid (SS), total Kjeldahl nitrogen and total phosphorus with the average removal efficiency of 94.6, 87.3, 83.6 and 89.9%, respectively. Total nitrogen (TN) removal was, however, not stable and the average removal efficiency was 65.5%. The contribution of the number of the treatment stages was significant only for SS removal. Among three conditions, the best performance was obtained with unvegetation under unsaturated condition. The results of this study implied insufficiency of mature of reed rhizosphere during the study period. Even negative effect of the vegetation on the treatment feasibility in winter during start-up operation was suggested.
