Assessing the potential use of composite titanium-containing coagulants, when treating wastewater from copper compounds

Abstract

Wastewater treatment from heavy metals is a complicated and currently relevant task. Electrochemical coating processes are undoubtedly a main source of heavy metal compounds in wastewater. The second major source of heavy metal input to the environment is mining and processing of various ores. As part of the conducted research, the author assessed a potential intensification of wastewater treatment from copper compounds, using conventional and titanium-containing chemical agents. The samples taken for research were wastewater from electroplating facilities, containing copper compounds, rinse waters after neutralization and sedimentation, and mine waters. It is found that the use of pure titanium salts (titanyl sulfate) contributes to achieving the minimum residual concentration of copper compounds for all the wastewater samples under study; however, their extremely high cost makes this process economically impractical. Composite titanium-containing chemical agents produced by modification of aluminum sulfate with added titanium compounds significantly increased efficiency of the base chemical agent and reduced the residual concentration of copper in wastewater by almost 30%. Iron-containing coagulant was not efficient for the task. Factoring into a minimum amount of added titanium compounds (5–10 % wt.), the cost of composite titanium-containing chemical agents is slightly higher than the cost of pure aluminum sulfate, while the lower residual concentration of copper will significantly reduce the amount of penalties from the regulatory authorities for discharging pollutants into the city drainage main above the limit. It is stated that composite titanium-containing coagulants also contribute to a significant increase in efficiency of removing suspended particles and the coagulation sludge sedimentation rate, entailing reduced sizes of wastewater treatment facilities or their increased performance.The author gratefully acknowledges Natalia E. Kruchinina, research advisor, Doctor of Engineering Sciences, Professor, Head of the Industrial Ecology Department.The measurements were made using equipment of the Mendeleev Research Equipment Sharing Center.