EFFECTS OF NITRILOTRIACETIC ACID-NICKEL COMPLEXES ON ACTIVATED-SLUDGE PROCESS

Effects of nitrilotriacetic acid (NTA), nickel ion (Ni2+) and their complexes on the efficiency of biological wastewater treatment, activated sludge process, were evaluated by determining the changes in physical and chemical parameters. Primary effects of these toxicants on microorganisms in the activated sludge process were evaluated by determining the change of in vivo dehydrogenase activity. The presence of 10 mg/L or higher of Ni2+ significantly affected the activated sludge process. Nitrification in the activated sludge process was more sensitive to the inhibition of Ni2+. The presence of NTA, as high as 20 mg/L, didn't significantly affect the activated sludge process. Moreover, in the presence of 20 mg/L of NTA, the toxicity of Ni2+ on the activated sludge process was significantly reduced.