SOIL AQUIFER TREATMENT OF SECONDARY EFFLUENTS AND CSOS IN SOUTHWESTERN ONTARIO

摘要

Wastewater reclamation is becoming an important alternative for sustainable water resources management and building climate change resiliency in many regions around the world. The purpose of this research was to investigate the polishing of secondary effluents and Combine Sewer Overflows (CSOs) by a laboratory scale Soil Aquifer Treatment (SAT) considering local sub-surface geology and wastewater characteristics. Results show that characteristic soils of southwestern Ontario can effectively polish secondary effluents in terms of BODs (64.9% to 100%), e-coli (100%) and total coliforms (100%). However, low removals of DOC (22.81%) and Nitrate (15.17 %) were achieved. Furthermore, low to moderate improvements of CSOs quality were observed with maximum removals of 54.26 % for BOD5, 36.67% for e-coli, 58.15% for total coliforms and 44.83 % for Total Nitrogen. Additionally, de-nitrification of secondary effluents was greatly improved (46.1 % to 100%) by the addition of readily available organic matter, which supports the importance of protecting recharge wetlands for groundwater quality protection. SAT in southwestern Ontario is a feasible alternative for the recharge of non-potable and potable aquifers with secondary effluents. However, for potable aquifers further treatment of wastewater effluents may be required.