Effects of Nitrolotriacetic Acid-Copper Complexes on Activated Sludge Process

Effects of nitrilotriacetic acid (NTA), copper ion (Cu2+) and their complexes on the efficiency of activated sludge process were evaluated by determining the changes in physical and chemical parameters in a laboratory-scale unit. Primary effects of these toxicants on microorganisms in the activated sludge process were also evaluated by determining the change of in vivo dehydrogenase activity. The presence of 1 mg L-1 or higher of Cu2+ significantly affected the activated sludge process. Nitrification in the activated sludge process was more sensitive to the inhibition of Cu2+. The presence of NTA, as high as 20 mg L-1, did not significantly affect the activated sludge process. Moreover, in the presence of 20 mg L-1 of NTA, the toxicity of Cu2+ on the activated sludge process was significantly reduced.