沸石联合固定化微生物技术抑制沉积物氨氮释放

Study on Mechanism of Removing Ammonium from Water by Clinoptilolite-microbe Combined Immobilization Technology

以扬州古运河沉积物为对象,将从中驯化分离到的土著硝化、反硝化细菌固定于斜发沸石之上,构建原位联合修复技术,并应用于试验水体。着重考察斜发沸石吸附-解吸特性及挂膜前后对沉积物NH+4-N释放的抑制效果差异。结果表明:25℃下,斜发沸石对NH+4-N去除率可达90%以上,吸附极限4.761 905 mg/g,吸附过程符合Langmuir等温模型。温度上升有利于沸石对NH+4-N吸附。斜发沸石去除NH+4-N以离子交换为主,吸附为辅,在不同的NH+4-N浓度序列下(10～300 mg/L),KCl溶液对沸石的解吸率均高于NaCl和CaCl2溶液。通过结合固定化微生物技术,挂膜沸石NH+4-N去除率高于无生物膜沸石(前者12 d接触去除率达94.64%),可有效抑制沉积物NH+4-N释放;并兼具脱氮功能,从而降低污染底泥氮负荷。

By taking the sediments from Yan-zhou ancient canal as main research object,the native nitrifying and denitrifying bacteria acclimated and separated from the sediments were fixed on clinoptilolite to build clinoptilolite-microbe combined immobilization technology and apply in the test water.Through the experiment,adsorptiondesorption characteristics of clinoptilolite were analyzed and inhibition effect of sediment NH4＋-N release before and after biomembrane hanging was compared.The results show that under 25 ℃,the removal rate of NH4＋-N by clinoptilolite can be more than 90％ and the maximum adsorption content is 4.761 905 mg/g,which is in accordance with Langmuir adsorption isotherm model.However,temperature rise can promote above process.The priority way of removing NH4＋-N by clinoptilolite is ion exchange and adsorption is only considered auxiliary.Under different initial concentration of NH4＋-N in test water（10 ～ 300 mg/L）,the desorption rate of clinoptilolite in KCl solution are higher than that of NaCl and CaCl2 solutions.According to the technology of clinoptilolite-microbe combined immobilization,the removing rate of NH4＋-N by biofilm culturing clinoptilolite are higher than membraneless clinoptilolite （the removing rate of NH4＋-N by the former can up to 94.64％ after 12 days）,which can effectively inhibit sedi ment NH4＋-N release,as well as denitrifying,thus reducing nitrogen load in polluted sediments simultaneously.