Domestic wastewater treatment using batch-fed constructed wetland and predictive model development for NH3-N removal

In this study, the performance of a pilot-scale batch-fed constructed wetland in treating domestic wastewater from small community was tested. The principal of the system capitalizes on the pollutant removal mechanisms of the soil-plant-microbial interactions of constructed wetlands, and the system operation was integrated with the rhythmical movement of wastewater and air that similar to the operation of conventional sequencing batch reactor. Based on the hydraulic loading of 0.91 m(3)/m(2)/day and the daily maximum contact time of 18 h, the system could achieve around 60% removal efficiency for carbonaceous matters. The removals of ammonia nitrogen and phosphorus were about 50 and 40%, respectively, while the removal of total suspended solids was approaching 80%. Mathematical models were developed to describe ammonia nitrogen degradation in the batch-fed constructed wetland. Three analytical approaches including multivariate regression, first-order kinetics and mass balance analysis were done. Prediction model was formulated to predict the system removal efficiency of ammonia nitrogen. (C) 2007 Elsevier Ltd. All rights reserved.