Effect of Temperature on the Sewage Treatment by Iron-Enhanced Activated Sludge

Iron-enhanced activated sludge was developed to solve the problem that the nitrification efficiency was poor in low temperature. Removal efficiency of COD_Cr, NH₄⁺-N and PO₄³-P by iron-enhanced activated sludge were investigated by using integrated biological reactor in common temperature and low temperature. And the transformation law of nitrogen and phosphorus treated by iron-enhanced activated sludge were studied. The results showed that the iron-enhanced activated sludge reactor could remove COD_Cr, NH₄⁺-N and PO₄³-P efficiently in common temperature when HRT was 8h. When iron content in activated sludge was lower than 10%, the effect of iron on the activated sludge was slight. In low temperature, NH₄⁺-N removal rate by iron-enhanced activated sludge was significantly higher than that by the comparative system. This indicated that the iron-enhanced activated sludge had good capability to tolerate low-temperature. Phosphorus release in anaerobic condition and phosphorus uptake and nitrification in aerobic condition by iron-enhanced activated sludge was higher than that by traditional activated sludge. In summary, the iron-enhanced activated sludge showed better nitrification ability in low temperature.