Water quantity and quality assessment on a tertiary treatment wetland in a tropical climate.
This study aimed to assess the quantity and quality of water in a surface flow constructed wetland in Australia's far north Queensland. Owing to tropical climate in the region, the wetland provided dual functions: retention of a treated wastewater for zero discharge during the dry season and tertiary treatment prior to discharge during the wet season. Rainfall data, permeability of wetland soil, evaporation, inflow and outflow were analysed in a water balance analysis; the results showed that based on a 72-year-average rainfall pattern, daily wastewater inflow of 85 m(3)/d is the maximum this wetland can cope with without breaching its discharge certificate. In water quality analysis, the K-C* model was used to predict changes of biochemical oxygen demand (BOD, suspended solids (SS), total nitrogen (TN), total phosphorus (TP) and faecal coliforms (FC) in the wetland. Model predictions were compared with field sampling results. It was found that the wetland was effective in removing FC (>99.9%), TN (70.7%) and TP (68.2%), for which the predictions by the K-C* model were consistent with field testing results. However, significant disparities between the predictions and testing results were found for BOD and SS. A revised K-C* equation was proposed to account for the internal generation of organics in constructed wetlands with a long retention time.
Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 4888 Shengbei Road, Gaoxinbei District, Changchun City 130102, Jilin, China E-mail: guangzhi.sun@jcu.edu.au; College of Science, Technology and Engineering, James Cook University, Building 15, 4811 Townsville, QLD, Australia.
Guangzhi
G
Sun
Department of Civil Engineering, Ahsanullah University of Science and Technology, Dhaka, Bangladesh.
Tanveer
T
Saeed
Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 4888 Shengbei Road, Gaoxinbei District, Changchun City 130102, Jilin, China E-mail: guangzhi.sun@jcu.edu.au.
Guangxin
G
Zhang
College of Science, Technology and Engineering, James Cook University, Building 15, 4811 Townsville, QLD, Australia.
Nagaratnam
N
Sivakugan
D001315:Australia; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D011793:Queensland; D012621:Seasons; D014329:Tropical Climate; D064091:Waste Disposal Facilities; D062065:Wastewater; D014867:Water / Q000032:analysis; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods; D060753:Water Quality; D053833:Wetlands
D009584:Nitrogen; D010758:Phosphorus; D062065:Wastewater; D014867:Water; D014874:Water Pollutants, Chemical