Mitigation of cationic polymer toxicity in industrial waters

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The release of water to the environment must meet specific environmental standards as set in industry operating permits (CCME, 1999). For many companies in land development, coagulation/flocculation treatment by cationic polymers is often used to remove suspended negatively charged (e.g., clays) particles (Total Suspended Solids; TSS). However, this potentially creates a secondary toxicity issue due to the presence of residual polymer, which is highly toxic to aquatic life. The overarching goal of this research project is to provide the necessary information to regulators required for approvals of an efficient, and cost-effective method for the amelioration of the toxicity of cationic polymer treated waters. The development of this process will benefit fisheries, environmental safety, and environmental compliance for industries that rely on cationic polymers to remove suspended sediments from wastewaters before discharge into natural environments. In collaboration with the industrial partner Clearflow group, we have developed a process to neutralize excess cationic polymers in water by the addition of a neutralizing agent. The amelioration of cationic polymer toxicity by the neutralizing agent is likely is affected by several factors, including the nature of the cationic polymers, the formulation of their polymer, and several parameters of water quality including pH, water hardness and humic acid, and dissolved organic carbon concentration. The goal is to devise a mathematically based model that can be used by industry to accurately predict the amelioration requirements for cationic contaminated municipal and industrial wastewaters before release. Inclusion of an amelioration process to eliminate cationic toxicity in industrial sites would prevent fish kills due to cationic polymer overdosing, thereby improving environmental compliance and raising the environmental profile of the companies/government bodies that dispose of their treated wastewater into natural, fish-bearing waters.