The effect of pH variation at the ammonium/ammonia equilibrium in wastewater and its toxicity to Lemna gibba
The effect of pH variation at the ammonium/ammonia equilibrium in wastewater and its toxicity to Lemna gibba
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DOI：
10.1016/s0304-3770(01)00158-9
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发表时间：
2001-09-01
期刊：
影响因子：
1.8
通讯作者：
Vermaat, JE
中科院分区：
文献类型：
--
作者：
Körner, S;Das, SK;Vermaat, JE
在不同的总氨浓度（10- 300mgN_1 ~（-1））和控制的pH值为6.8-8.7的条件下，使用沉降的生活污水进行实验室规模的分批实验，以测量离子化（NH_4 ~+或铵）和非离子化形式（NH_3）对浮萍生长的影响。相对生长率（RGR）在每天0 - 0.3之间变化。总氨对浮萍的毒性是在低NH_3浓度（<1mgN_1 ~（-1））时，电离态和非电离态两种形态作用的结果。在较高的NH3浓度下，电离形式的毒性作用可以忽略不计。相对生长率L.随着NH_3浓度的增加，浮萍的生长速率呈线性下降，当NH_3浓度达到最大值（8mgN_1 ~（-1））时，浮萍死亡。这些数据表明L. gibba可用于处理含有高总氨浓度的废水，只要不超过一定的pH水平。外推的相对增长率从不同的pH值和总氨的组合给出了检查范围。pH值高达7.8时，每天可获得55 kg DW/ha（-1）的产量。利用L. gibba在高于约9.8的pH水平下变得不可能，这取决于温度。(C)2001爱思唯尔科技有限公司。保留所有权利。
Laboratory scale batch experiments were performed under controlled conditions at different total ammonia concentrations (10-300 mg N l(-1)) and controlled pH values of 6.8-8.7 using settled domestic wastewater to measure the effect of the ionised (NH4+ or ammonium) and un-ionised form (NH3) on the growth of the duckweed Lemna gibba. Relative growth rates (RGR) varied between 0 and 0.3 per day. The toxicity of total ammonia to duckweed was a result of the effect of both, ionised and un-ionised, forms at low NH3 concentrations (< 1 mg N l(-1)). At higher NH3 concentrations, the toxic effect of the ionised form could be disregarded. Relative growth rates of L. gibba decreased linearly with increasing NH3 concentrations up to a maximum level (8 mg N l(-1)), above which duckweed died. These data indicate that L. gibba can be used to treat wastewater containing high total ammonia concentrations as long as certain pH levels are not exceeded. Extrapolated relative growth rates resulting from different combinations of pH and total ammonia are given for the examined ranges. Up to a pH of 7.8, a substantial production of 55 kg DW ha(-1) per day was achieved. Wastewater treatment using L. gibba becomes impossible at pH levels above approximately 9.8, depending on the temperature. (C) 2001 Elsevier Science B.V. All rights reserved.