【作者】 黄稳水；

【导师】 王继徽；

【作者基本信息】 湖南大学 ， 环境工程， 2004， 硕士

【摘要】 氨氮污染是引起水体富营养化的重要原因。水质复杂、处理效率低、处理成本高，一直是世界性石油化工废水脱氮处理急待解决的难题。本文通过对国内外文献的查新检索与试验研究，提出了以化学沉淀法回收石化高浓度氨氮废水中的氨氮的新方法。 本试验采用化学沉淀法原理，向废水中投加含Mg²⁺和PO₄^3-离子的药剂，使石化废水中的氨氮以磷酸铵镁（MgNH₄PO₄·6H₂O）的形式沉淀，从而有效去除废水中的氨氮污染物。在试验研究过程中，首先，通过大量试验确定最佳化学沉淀药剂为MgSO₄·7H₂O和Na₂HPO₄·12H₂O，搅拌速度100r／min，反应时间10min。其次，确定pH值、P：N配比、Mg：N配比和反应温度为影响反应平衡的主要因素，并采用正交试验方法和单因素优化试验，探讨得出反应的最佳工艺条件为：pH=9.0～9.5，P：N=1.0，Mg：N=1.2，并在该最佳工艺条件下进行试验，残留的氨氮浓度为20～30mg／L，余磷量一般小于10mg／L，为后续的生化处理创造了条件。然后，本研究对反应沉淀物的物理和化学性质进行了分析，结果表明，沉淀物的沉降性能较好（10min内SV指数可达20％），且单位体积废水的沉淀物产量及N、P、Mg含量与磷酸铵镁理论值相近；电镜及X衍射分析表明，沉淀物的主要成分为呈斜方晶系的磷酸铵镁晶体。最后，本文采用盆栽试验方法，以金盏菊、包菜花和石竹为例，探讨沉淀物的肥效和缓释性能。试验研究表明沉淀物可以缓慢释放养分，即使沉淀物施用过量对植物也不会产生烧伤现象；同时还可提高肥料中养分的吸收率，减少养分流失，这说明沉淀物具有缓释肥料的性质而且可以较好的应用于花卉植物的栽培，可以进一步开发为复合肥料，为此本研究也初步探讨了沉淀物逐步工业化的生产工艺。 以化学沉淀法回收石化高浓度氨氮废水中的氨氮，并把沉淀物作为缓释肥料在工业上加以应用，真正实现了“变废为宝”的目的，这在资源短缺的今天，是一种行之有效的方法。更多还原

【Abstract】 Ammonium-nitrogen is an important reason for causing the eutrophication of water body in petrochemical wastewater. Low treatment efficiency, high cost and large treatment system volume have become urgently solved problems at present. Based on a large number of papers and experimental researches, this paper put forward that the most promising ammonium-nitrogen removal process is chemical precipitation, which can recover the ammonium-nitrogen from petrochemical wastewater as magnesium ammonium phosphate precipitate.According to chemical precipitation theory, in the experiment, two chemicals containing Mg2+ and PO4~ ions were used to put into wastewater to generate the MgNH4P04-6H20 precipitation. So ammonium-nitrogen could be removed from wastewater as a precipitate effectively. Repeated experiments proved that optimum precipitators and stirring speed were selected as Na2HP04 12H20, MgSO4 7H2O and 100r/min, respectively. Then this experiment made use of orthogonal experiment and single optimizing experiment to determine optimum process parameters. The results indicated that ammonium-nitrogen contained in the petrochemical wastewater could be quickly reduced from 1480mg/L to below 30mg/L and surplus phosphate less than 10mg/L with 10 minutes. When Na2HP04-12H20 and MgS04-7H2O were added at a molar ratio of P:Mg:N=l:1.2:1, minimum concentrations of residual ammonium- nitrogen occurred between pH 9.0 and 9.5. Moreover, physical chemistry characterstics of the precipitatate were also studied in this experiment. And some results could be obtained: (1) the precipitate was easily settled; (2) SV was below 20 percent in 10min; (3) the precipitate yield and its composition of nutrition were similiar to the standard composition of MgNH4P04-6H2O; (4) SEM and X-ray figures indicated that the precipitate had a typical morphology of a short prismatic crystal, and its main compositon was magnesium ammonium phosphate. In addition, as Low solubility and containing N, P and Mg vegetable nutrition elements, the precipitate could be used as a fertilizer. To investigate the fertility of the precipitate, a set of pot trial testes was conducted. Three kinds of flowers, calendula officina lise, cabbage flower and dianthus chinens were cultivated in red earth and the precipitatewas applied as a fertilizer. The germination and growth of the selected flowers with the precipitate showed significantly greater growth ratios than those in the control pots without the precipitate. The experiment also demonstrated that over-dosing of about 2-8 times of the precipitate in the soil did not cause any problems with the flower, whereas add more precipitate, would stimulate vegetables growth. These tests proved that the precipitate as a slow release fertilizer was good for flowers’ growth. So this paper is also to preliminarily design the recovering process of ammonium-nitrogen from petrochemical wastewater, and to discuss the product process of the precipitate from small experiment to industrialization.Recovery of high concentration ammonium-nitrogen from petrochemical wastewater as a slow release fertilizer could turn waste into resource, which was proved to be an optimum method to deal with petrochemical wastewater.更多还原