| Contaminants remaining in industrial re-use water treated in surface-flow constructed wetlands can decrease power station cooling system efficiency. The effects of winter emergent biomass removal on water quality were examined in the SaskPower wetland at Estevan, Saskatchewan. Contaminants of concern examined included BOD5, TSS, TOC, P and Ca. Plant regeneration and nutrient uptake were measured to determine if nutrient removal could be achieved through targeted macrophyte harvest. Historical trends were examined to determine performance changes and contaminant removal parameters. Results indicated improved removal of BOD5 and TSS and either the same or decreased removal of TOC, P and Ca in the harvest area over the control area. Living plant biomass and associated phosphorus peaked in early July in the outflow, while plant calcium concentrations peaked in August in the inflow. Winter harvest may decrease biological fouling in product water, but summer harvest would be required to improve nutrient removal efficiencies. |
