Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6302872 | Ecological Engineering | 2011 | 9 Pages |
Abstract
This study aimed to evaluate the contaminant removal efficiency of shallow horizontal subsurface flow treatment wetlands (SSF TWs) as a function of (1) primary treatment (hydrolytic upflow sludge blanket (HUSB) reactor vs. conventional settling) and (2) operation strategy (alternation of saturated/unsaturated phases vs. permanently saturated). An experimental plant was constructed, operated and surveyed for the main water quality parameters over a period of 2.5 years. The plant had 3 treatment lines: a control line (settler-wetland permanently saturated), a batch line (settler-wetland operated with saturated/unsaturated phases) and an anaerobic line (HUSB reactor-wetland permanently saturated). In each line wetlands had a surface area of 2.80 m2, a water depth of 25 cm and a granular medium D60 = 7.3 mm, and were planted with common reed. During the study period the wetlands were operated at a hydraulic and organic load of 28.5 mm/d and about 4.7 g BOD/m2 d, respectively. Effluent average redox potential was lower for the anaerobic line (â45 ± 78 mV) than for the other two lines (3 ± 92.7 and â5 ± 71 mV for control and batch, respectively). Overall, chemical oxygen demand (COD), biochemical oxygen demand (BOD5) and ammonium mass removal efficiencies were slightly greater for the batch line (88%, 96% and 87%, respectively) than for the control line (83%, 94% and 80%) and the anaerobic line (80%, 87% and 73%). During cold seasons, COD and ammonium removal in the batch line was around 30% and 50% higher than in the control line, respectively. The results of this study indicate that the implementation of a HUSB reactor as primary treatment did not enhance the treatment capacity of the system (in comparison with a conventional settler). The efficiency of treatment wetland systems with horizontal subsurface flow can be improved using a batch operation strategy.
Related Topics
Life Sciences
Agricultural and Biological Sciences
Ecology, Evolution, Behavior and Systematics
Authors
Anna Pedescoll, Angélica Corzo, Eduardo Álvarez, Jaume Puigagut, Joan GarcÃa,