Enhancing the removal of pollutants by an on-stream pond

Abstract

A methodology is presented for assessing the pollution control performance of an on-stream pond located in Kingston, Ontario, Canada, and enhancing the removal of pollutants by remediation techniques., Descriptions are provided of the instrumentation used to measure continuously rainfall and water levels, and the sampling program to collect stormwater samples., The assessment is based on examining contaminant removals for both baseflow and event conditions and applying in-pond remedial measures to improve pond performance., Results on removal rates are provided for selected dissolved constituents (total dissolved solids, sulphate and chloride), nutrients, suspended solids, metals and organic contaminants., In summary, dissolved constituents exhibit zero removal for baseflow periods and positive removal for events; nutrients and suspended solids exhibit negative removal for baseflow periods and positive removal for events; and metals and organics exhibit positive removal for both baseflow periods and events. Remediation techniques are discussed and preliminary results of one technique — internal pond baffles — indicate that extended hydraulic residence times and prevention of flow short-circuiting result in increased particulate settling and associated contaminant removal.