Integrated Constructed Wetlands for Rural Domestic Wastewater Treatment:

The paper reports the treatment performance capability, during an on-going full-scale study, which was set to evaluate the novel concept of integrated constructed wetlands (ICW) for domestic wastewater treatment in Ireland. The ICW at the center of this study is located at Glaslough in Co. Monaghan, Ireland. The 3.25 ha ICW comprises of two sludge cells and a sequence of five shallow vegetated wetland cells, and receiving primary domestic wastewater. Overall, mass removal rates greater than 90 % were achieved for suspended solids, organic matter and nutrients during the monitoring period (February 2008 to June 2011). A direct correlation of organic loading on its removal rates was sustained over the entire period of monitoring, and indicated that the ICW had capacity for increased organic loads and could still be operated beyond the maximum ranges received during the course of this study. Nutrients removal, however, was slightly variable. Kinetic coefficients estimated for nutrients removal in the ICW indicated that nutrients removal was largely dependent on temperature, and showed a reduced removal rate under freezing conditions and under higher hydraulic loading rates. Enlarging the system to provide a longer hydraulic retention time can therefore, optimize the nutrient removal during such periods