氧化强化对氢氧化钙原位固磷效果的影响

将氢氧化钙［Ca（OH）₂］和过氧化氢（H₂O₂）以梅花散点的方式注射到底泥中，考察两者联用对内源磷的控制效果.结果表明，单独投加Ca（OH）₂可以有效固定沉积物-水界面（SWI）以下约20 mm沉积物中约90%的内源磷，但同时会加剧20 mm以下沉积物的厌氧环境，导致沉积物中稳定态磷向易释放态磷转化，造成潜在活性磷的累积；而H₂O₂的加入极大地降低了Ca（OH）₂投加后深层沉积物潜在活性磷富集的风险，并明显提高了Ca（OH）₂在沉积物中的纵向扩散深度，其影响范围可以达到SWI以下0~40 mm；但40 mm以下沉积物影响并不明显；这主要归因于氧化剂的投加导致氧化还原电位提高了近18倍.底泥内源磷形态变化也证实了氧化剂投加对磷的良好固定效果.与对照实验相比，SWI以下0~20 mm沉积物中易释放态磷含量明显降低，同时沉积物中Ca-P含量增加了约10%.但随着底泥深度增加，易释放态磷减少量逐渐降低，Ca-P的增加也逐渐变缓.

Effect of Oxidation Strengthening on In-situ Phosphorus Immobilization of Calcium Hydroxide

In this research, calcium hydroxideCa(OH)₂] and hydrogen peroxide (H₂O₂) were injected into the bottom mud in the form of plum blossom scatterers to investigate the effect on the control of endogenous phosphorus. The results showed that Ca(OH)₂ used singly effectively immobilized in the order of 90% of endogenous phosphorus approximately 20 mm below the sediment-water interface (SWI); however, at the same time, the anaerobic environment was enhanced, resulting in the transformation of stable phosphorus to easily released phosphorus and the accumulation of potential active phosphorus. Nevertheless, the addition of H₂O₂ greatly reduced the amount of potential active phosphorus in deep sediments after adding Ca(OH)₂. The vertical diffusion depth of Ca(OH)₂ in the sediments was significantly increased, having an influence across the depth range of 0-40mm below the SWI; the improvement at depths greater than 40 mm was not notable, which was mainly attributed to an 18-fold increase of redox potential due to the addition of the oxidant. The change of phosphorus forms in the sediment also demonstrated the excellent immobilization effect of the oxidant on phosphorus. In the 0-20 mm layer, the content of readily released phosphorus decreased significantly, while compared with a control test, Ca-P increased by approximately 10%. However, at greater depths, the amount of easily released phosphorus decreased and the rate of Ca-P increase gradually slowed.