小流域农业非点源污染物磷迁移转化过程及控制研究

发布时间：2018-06-12 08:31

本文选题：农业非点源污染 + 磷的迁移转化　；参考：《南昌大学》2015年博士论文

【摘要】：研究表明,海岸、湖泊中磷主要来自农业非点源地表径流流失。为寻求磷的迁移转化规律以及适宜的控制措施,本文选择鄱阳湖小流域为研究区域,采用参与性农村评估(Participatory Rural Appraisal,PRA)方法调查,并从"源-流-汇"三方面探讨磷的迁移转化规律以及相对应的控制措施。1.磷"源"的迁移转化过程:由PRA调查可知示范区小流域非点源污染主要来源为种植业,其中化肥造成的磷污染浓度最高。施磷和培养时间对稻田土壤无机磷含量及CaCl2-P、生物可利用磷(Bio-available Phosphorus,BAP)、溶解性活性磷(Dissolved Reactive Phosphorus,DRP)含量影响的实验结果都表明,磷肥的施用会大大增加磷向水体迁移转化的机率。利用分段回归模型,分别对Olsen-P和CaCl2-P含量以及Olsen-P和Pw含量拟合,所得土壤环境敏感磷临界点对应的土壤Olsen-P含量数值相差不大。当施磷量超过138.16kg/ha时,提高了土壤磷流失风险。控制施肥量是控制磷"源"的迁移转化的关键。2.磷"流"的迁移转化过程:植物缓冲带和田间生态沟渠是磷"流"迁移转化的重要途径。植物缓冲带依靠植物长久并有效拦截以颗粒态为主的污染物。通过种植不同植物对比,可知百慕大对颗粒态磷的截留能力大于其他植物。沟渠内干湿交替会引起沉积物瞬间产生磷迁移至水体的现象,通过采取减缓流速、延长土壤与水的接触时间以及预先排水让微生物适应干湿交替的变化,可以降低磷的总流失量。沟渠内沉积物主要由无机磷组成,且其中主要成分为NaOH-P(Fe/Al-P)。X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)结合能数据显示,pH值不会造成电子转移,磷以HPO42-形式与OH-竞争吸附。实验数据也表明中性状态下磷酸盐释放量最小,酸性及碱性状态下都会造成沉积物磷的释放而碱性状态沉积物磷释放量更大;XPS数据显示氧气的充入引发了电子转移,Fe2+被氧化为Fe3+,吸磷量增加;XPS数据亦显示照度通过生物过程影响上覆水中溶解氧(Dissolved Oxygen,DO)、pH,间接影响沉积物磷的迁移转化。但照度对沉积物磷释放影响规律性不强,总体来说有光组释放量大于无光组。合理配置(减缓水流速度,延长接触时间)、完善生态系统是控制磷"流"迁移转化的重要途径。3.磷"汇"的迁移转化过程:湿地、生物塘对磷的迁移转化过程的影响主要体现在汇集、滞留并最终成为一个磷的滞留储备库,充分发挥基质、微生物、植物的协同作用更有利于磷的良性循环。通过对湿地磷平衡浓度(Equilibrium Phosphorus Concentration,EPC0)实验得出示范基地湿地的基质-水界面的EPC0浓度为0.050mg/L,去污能力较强。由耐负荷实验研究可知,新建湿地对磷具有很强的耐负荷冲击能力。碳源的加入有助于充分发挥湿地内微生物的除磷作用。由实验可知,加入碳源比未加碳源,湿地对磷的截留有所增加,其中植物碳源的最终效果优于葡萄糖有机液态碳源。植物对磷的去除率存在一定的影响,植物生长高度和磷的去除率之间存在线性关系(R2=0.71)。植物收割后磷的去除率亦有所提高。通过利用"控源—截污—再利用"(Controlling-Intercepting-Recycling,CIR)模式,不仅可以实现氮、磷流失的有效拦截,还可产生良好的经济效益。此模式包括三方面:一是改变农村生活、耕作不良习惯及方式等从源头上控制污染物的排放;二是合理配置植物缓冲带、沟渠湿地等达到控流的目的;三是利用生物塘、湿地等汇集滞留营养物并通过植物实现磷的良性循环。经过16个月的运行测试,系统单位面积削减总量分别为CODcr 755.71kg/m2、SS 135.31kg/m2、TP4.23kg/m2、TN36.38kg/m2,而运行成本不到0.10元/吨。整个系统中尤以人工湿地减污效果最好,耐负荷冲击能力最强。
[Abstract]:The research shows that the phosphorus in the coastal and lake is mainly from the runoff loss of agricultural non point source surface. In order to seek the migration and transformation of phosphorus and the appropriate control measures, this paper chooses the Poyang Lake small watershed as the research area, investigates the participatory rural assessment (Participatory Rural Appraisal, PRA), and discusses phosphorus from the three aspects of "source flow sink". The migration transformation rule and the corresponding control measures.1. phosphorus "source" migration and transformation process: from the PRA survey, the main source of non point source pollution in the small watershed of the demonstration area is the planting industry, in which the phosphorus pollution caused by the fertilizer is the highest. The phosphorus and culture time on the soil inorganic phosphorus content and the CaCl2-P, the bioavailable phosphorus (Bio-available P) Hosphorus, BAP), the experimental results of the effects of Dissolved Reactive Phosphorus (DRP) content all show that the application of phosphate fertilizer will greatly increase the probability of phosphorus migration and transformation to the water body. By using the piecewise regression model, the content of Olsen-P and CaCl2-P and the content of Olsen-P and Pw are fitted, and the corresponding critical point of soil environmental sensitive phosphorus is obtained. The Olsen-P content of soil varies little. When the amount of phosphorus exceeds 138.16kg/ha, it increases the risk of soil phosphorus loss. The control of fertilization is the transfer and transformation process of the key.2. phosphorus "flow", which controls the migration and transformation of phosphorus "source": plant buffer zone and field ecological ditch are important ways of phosphorus "flow" migration and transformation. Plant buffer zones depend on plant length. For a long time, it effectively intercepts particulate matter. By planting different plants, it can be found that Bermuda's ability to intercept particulate phosphorus is greater than that of other plants. The alternation of dry and wet in the ditch will lead to the transient migration of phosphorus to the water body. By taking slow flow rate, prolonging the contact time between soil and water and pre drainage. The total loss of phosphorus can be reduced by adapting the microorganism to the alternation of dry and wet alternation. The sediment in the ditch is mainly composed of inorganic phosphorus, and the main component is NaOH-P (Fe/Al-P).X ray photoelectron spectroscopy (X-ray photoelectron spectroscopy, XPS) binding energy data showing that pH does not cause electron transfer, and phosphorus is competing with OH- in HPO42- form. The experimental data also showed that the release of phosphate in the neutral state was the smallest, and the phosphorus release from the sediments in the acid and alkaline state would cause the release of phosphorus in the alkaline state, while the XPS data showed that the oxygen was filled with the electron transfer, the Fe2+ was oxidized to Fe3+, the amount of phosphorus absorption increased, and the XPS data also showed that the illumination was reflected through biological process. Dissolved Oxygen, DO and pH indirectly affect the migration and transformation of phosphorus in sediment, but the regularity of the impact of illumination on phosphorus release is not strong. In general, the release amount of light group is greater than that of the non light group. The migration and transformation process of.3. phosphorus "sink": wetland, the influence of biological pond on phosphorus migration and transformation is mainly reflected in the accumulation, detained and eventually become a phosphorus retention reserve, giving full play to the substrate, microorganism, plant synergy is more conducive to the benign cycle of phosphorus. Through the equilibrium concentration of phosphorus in wetland (Equilibrium Phosphorus Conce) Ntration, EPC0) experiments show that the EPC0 concentration of the matrix water interface of the demonstration base wetland is 0.050mg/L, and the decontamination ability is strong. It is known from the experimental study of load resistance that the new wetland has a strong load resistance impact ability to phosphorus. The addition of carbon source will help to give full play to the phosphorus removal effect of microorganism in the wetland. With the carbon source, the removal of phosphorus is increased, and the final effect of plant carbon source is better than that of the organic liquid carbon source of glucose. There is a certain effect on the removal rate of phosphorus. There is a linear relationship between plant height and phosphorus removal rate (R2=0.71). The removal rate of phosphorus after harvest is also improved. Pollution and reuse (Controlling-Intercepting-Recycling, CIR) model not only can effectively intercept the loss of nitrogen and phosphorus, but also produce good economic benefits. This model includes three aspects: one is to change rural life, bad farming habits and ways to control the emission of pollutants from the source, and two is the rational allocation of plant buffer zones. The purpose of canal wetland is to achieve the control of the current. Three is to use the biological pond, the wetland to collect the remaining nutrients and realize the benign cycle of phosphorus through the plant. After 16 months' operation test, the total amount of unit area reduction is CODcr 755.71kg/m2, SS 135.31kg/m2, TP4.23kg/m2, TN36.38kg/m2, and the operating cost is less than 0.10 yuan / ton. In particular, the constructed wetland has the best anti pollution effect and the strongest load impact resistance.
【学位授予单位】：南昌大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：X71

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