Nikolić A, Hultman B
Department of Land and Water Resources Engineering, Royal Institute of Technology (KTH), Brinellvägen 32, S-100 44 Stockholm, Sweden.
Water Sci Technol. 2005;52(10-11):509-16.
A new system that removes nitrogen from landfill leachate and other waste waters with similar properties has been proposed with nitritation (i.e. oxidation of ammonium to nitrite) of half of the influent ammonium followed by chemical denitrification with a reaction between equal amounts of ammonium and nitrite to form nitrogen gas. Chemical denitrification occurs at high concentrations and the reactions were studied in combination with a concentration step. Studied concentration methods were freezing/thawing and evaporation/drying. Chemical denitrification is well-known in inorganic chemistry and has been observed in natural systems. Studies in laboratory were focused on chemical denitrification and showed that nearly complete removal of soluble nitrogen can be obtained in evaporation/drying of water solutions or leachate with equal amounts of ammonium and nitrite. Freezing/drying was less efficient with a removal of about 50-60% at high initial concentrations. Chemical denitrification is much influenced by concentration, pH-value, temperature and some compounds in leachate have an inhibiting effect on the reaction. Factors as safety (ammonium nitrite as a salt is explosive above 60 degrees C) and possible side-reactions as formation of ammonia and nitrogen oxides must be carefully evaluated before use in full-scale. Conductivity is a suitable parameter to follow-up the chemical denitrification process.
一种新的从垃圾渗滤液和其他具有类似性质的废水中去除氮的系统被提出来了，该系统是将一半的进水铵进行亚硝化（即将铵氧化为亚硝酸盐），然后通过等量的铵和亚硝酸盐之间的反应进行化学反硝化以形成氮气。化学反硝化在高浓度下发生，并且结合浓缩步骤对这些反应进行了研究。所研究的浓缩方法是冷冻/解冻和蒸发/干燥。化学反硝化在无机化学中是众所周知的，并且在自然系统中也已被观察到。实验室研究集中在化学反硝化上，结果表明在含有等量铵和亚硝酸盐的水溶液或渗滤液的蒸发/干燥过程中，几乎可以实现可溶性氮的完全去除。冷冻/干燥效率较低，在高初始浓度下去除率约为50 - 60%。化学反硝化受浓度、pH值、温度的影响很大，并且渗滤液中的一些化合物对该反应有抑制作用。在大规模应用之前，必须仔细评估诸如安全性（亚硝酸铵作为一种盐在60摄氏度以上具有爆炸性）以及可能的副反应（如氨和氮氧化物的形成）等因素。电导率是跟踪化学反硝化过程的一个合适参数。
