酸化法回收高效沉淀池污泥中的铝及其除磷效能

Recovery of Aluminum in Sludge from High Efficiency Sedimentation Tank by Acidification Method and Its Phosphorus Removal Performance

为提高铝的回收率,从高效沉淀池污泥的特点出发,采用酸化法浸出高浓度的铝进行回收利用。探究了pH、反应时间对铝浸出浓度的影响,并利用高浓度铝回收液作为除磷药剂考察其对污水中磷的去除效果。结果表明,酸化pH越低,铝浸出浓度越高;当酸化30 min时,反应基本完成,后续铝浸出浓度基本不变;回收液中铝浓度可高达3000 mg/L,当其添加量为2.0%时,对污水中磷的去除效果显著,去除率可达86.3%。对铝进行回收可以减少污水厂中聚合氯化铝(PAC)的投加量,降低污水厂的实际运行成本。

High‑concentration aluminum was leached and recovered by acidification method according to the characteristics of sludge from high efficiency sedimentation tank,so as to improve the recovery rate of aluminum.The effects of pH and reaction time on the leaching concentration of aluminum were investigated,and the removal performance of phosphorus from wastewater was explored by using the recovered high‑concentration aluminum liquid as the phosphorus removal agent.The aluminum leaching concentration increased with the decrease of acidification pH.After acidification for 30 min,the reaction was basically completed,and the subsequent leaching concentration of aluminum tended to be stable.The concentration of aluminum in the recovered liquid was as high as 3000 mg/L.When the dosage of the recovered liquid was 2.0%,the removal performance of phosphorus in wastewater was remarkable,and the removal rate reached 86.3%.The recovery of aluminum can decrease the dosage of polymeric aluminum chloride(PAC)in the wastewater treatment plant and reduce its operating cost.