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| Effect of Cu (Ⅱ) and Zn (Ⅱ) on nitrogen removal efficiency in anammox sludge |
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Abstract The effects of copper and zinc ion concentration on nitrogen removal efficiency were studied in short or long term by inoculating anammox sludge. The influence of copper and zinc ion in anammox sludge was mainly divided into three stages in the short-term. The stimulus phase, anammox bacteria activity was stimulated and the nitrogen removal rate increased rapidly with the increase of concentration of copper ion and zinc ion from 0mg/L to 1mg/L and from 0mg/L to 4mg/L respectively. The stabilization phase, the nitrogen removal rate in steady state with the concentration of copper ion increased from 1mg/L to 8mg/L. The Inhibition phase, the nitrogen removal rate decrease gradually with the increase of the concentration of copper ion or the zinc ion greater than 8mg/L and 4mg/L. Copper ions and zinc ions on anammox sludge nitrogen removal efficiency of long-term effects showed that, the nitrogen removal rate decrease rapidly and the sludge activity would be inhibited when the influent concentration of copper ion at 4mg/L and zinc ions to achieve 8mg/L. Anammox sludge activity can be recovery when reduce the influent concentration of heavy metals. Copper ion more susceptible than the zinc ion on anammox bacteria.
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Received: 14 August 2013
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