A CO2 stripping packed layer was built in the inner pipe of a double pipes phosphorus recovery reactor, so as to develop a new unit and technology for phosphorus recovery from wastewater by struvite, and its CO2 stripping performance and phosphorus recovery efficiency were studied in this paper. It was showed that:CO2 could be stripped out quickly by the unit with a little height of packed layer, and pH of wastewater can be raised from 7.0 to 8.0 in a few minutes. Both ammonia nitrogen and phosphorus in the wastewater have an inhibiting effect on the raising of pH, and the inhibition of phosphorus is much greater, but both of them does not influence the consumed amount of the alkali needed, and on the contrary which can be saved about 20%with the stripping operation; moreover, the phosphorus recovery efficiency could be raised about 2%~5% by using the proposed technology, and the phosphorus recovery can be realized under the conditions of a lower pH and less molar ratios of ammonia nitrogen and magnesium to phosphorus, the recovery could reach up to 92%in generally and to 95% at the best. As a result, the phosphorus recovery cost can be reduced. The results also show that:phosphorus recovery efficiency increase with the increases of pH, initial phosphorus concentration and both the molar ratios of ammonia nitrogen and magnesium to phosphorus;when initial phosphorus concentration is less than 77.5 mg×L-1 or molar ratios of ammonia nitrogen or magnesium to phosphorus are less than 2 or 1.2 respectively, the phosphorus recovery efficiency increases sharply with the increase of above mentioned parameters;however, it increases very little when these parameters reach beyond their turning points.%将填料层二氧化碳脱气柱合建在套管式磷回收装置的内套管上部，建立了一种新型的套管式空气脱气填料层鸟粪石法磷回收装置及其工艺，并详细研究了其脱气性能和磷回收效率。结果表明：该装置对废水中二氧化碳的脱除速度快、效果好，废水的pH值可从7.0迅速提升至8.0左右；废水中的氮磷对pH的提升都有抑制作用，磷的抑制作用尤为明显，但氮磷的存在对耗碱量的减少比例都没有影响，碱用量平均节省约20%；该工艺可提高磷回收率2%~5%，并可在较低的pH值-氮磷比和镁磷比的条件下实现磷回收，节省磷回收成本。研究结果还表明：磷回收率随pH值、磷初始浓度、氮磷和镁磷摩尔比的增大而升高，当后三个参数分别小于77.5 mg×L-1、2和1.2时，磷回收率随参数值的增大都迅速升高，但当这些参数大于其拐点值后，磷回收率继续升高的幅度都不大。
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