¹Department of Civil & Structural Engineering, The Hong Kong Polytechnic University, Hong Kong SAR
²Polytechnic University-Harbin Institute of Technology Joint Research Centre for Water and Wastewater Technology, The Hong Kong Polytechnic University, Hong Kong SAR

*Corresponding author: jackiesychanm@yahoo.com.hk

Abstract

   A lab-scale vertical flow cinder bed was set up to treat domestic wastewater. Cinder, which is a common coal waste from electricity generation, was used as the filter medium in the six vertical flow column beds in this study. Three of the six columns were planted with umbrella grass (Cyperus alternifolius) to mimic a wetland system and to investigate the effects of plant on the pollutant removal efficiencies of the column bed systems. The six column beds were divided into three groups, operating with different durations of “wet” and “dry” periods. Group 2 column beds, with 4 hours “wet” periods and 4 hours “dry” periods, showed the highest carbonaceous removal. And similar ammonia nitrogen removal efficiencies were demonstrated in column beds of group 2 and in column beds of group 3 (6 hours “wet” periods and 2 hours “dry” periods). Phosphorus removal efficiencies were not significantly different in all groups of column bed. No significant differences in pollutant removal were observed between planted and unplanted column beds in this study (p>0.05).