Yoshino M, Yao M, Tsuno H, Somiya I
Maezawa Industries, INC., 5-11, Naka-cho, Kawaguchi-shi, Saitama 332-8556, Japan.
Water Sci Technol. 2003;48(1):171-8.
Removal of phosphorus and nitrogen is required to prevent eutrophication problems in lakes and enclosed coastal seas. And recovery of phosphorus from wastewater has been attracting attention because of lack in phosphorus resources in the near future. In this study, reaction kinetics and design parameters of struvite production are experimentally investigated by using basic reaction type and a draft-tube type reactors. Struvite production rate, which is a very important parameter in reactor design and efficiency estimation, is formulated in an equation consisting of a rate constant (k2), and magnesium, phosphate and ammonium concentrations. The value of k2 is shown to be increased with struvite concentration and mixing intensity in the reactor. The developed equation is applied to the results obtained from the draft-tube type reactor experiments and verified for its applicability. High struvite concentration of 10-25% is maintained in the draft-tube reactor experiments. 92% removal and recovery efficiency with effluent phosphorus concentration of 17 mg/L is achieved under the conditions of 4 minutes reaction time, pH of 8.5 and Mg/P molar ratio of 1.1.
为防止湖泊和封闭沿海海域出现富营养化问题，需要去除磷和氮。由于在不久的将来磷资源短缺，从废水中回收磷一直备受关注。在本研究中，通过使用基本反应型和导流管型反应器，对鸟粪石生产的反应动力学和设计参数进行了实验研究。鸟粪石产率是反应器设计和效率评估中非常重要的参数，它由一个速率常数（k2）以及镁、磷酸盐和铵的浓度组成的方程来表示。结果表明，k2的值会随着鸟粪石浓度和反应器内混合强度的增加而增大。将所建立的方程应用于导流管型反应器实验获得的结果，并验证了其适用性。在导流管反应器实验中，鸟粪石浓度保持在10%-25%的较高水平。在反应时间为4分钟、pH值为8.5、镁/磷摩尔比为1.1的条件下，实现了92%的去除和回收效率，出水磷浓度为17毫克/升。
