减轻白马湖周边农业面源污染的对策研究

发布时间：2018-06-20 01:44

  本文选题：白马湖 + 农业面源污染　； 参考：《扬州大学》2017年硕士论文

【摘要】：近年来,白马湖周边地区的农业面源污染日益加剧,其所含的氮、磷污染物进入大气、土壤和水体后,对水环境和生态系统造成了严重的破坏。根据野外实地考察,白马湖周边农业面源污染来源主要包括种植业、养殖业、农村生活污水等方面。农业面源污染的发生与发展过程历经“源—流—汇”3个阶段。针对这3个阶段,本文提出了非点源污染的源头控制技术、对污染物向附近水体传递过程中的截留控制技术、末端污水净化处理技术。白马湖流域是水稻种植区,这一地区农田分布着纵横交错的灌溉渠道和排水沟道。排水沟道作为农业和农村生活污水的最初汇聚地,是农业面源污染物进入河流的通道。因此,研究沟道系统中氮、磷的迁移转化是农田面源污染控制和治理的关键。为有效阻控农田土壤流失氮、磷污染物通过排水沟道进入周围水体,在总结国内外农田面源污染控制技术的基础上,本文设计出一种在农田排水沟中的新型生态过水堰,在不影响农田沟道日常排水的前提下,能够截留净化污水,减少土地使用面积。首先在人工开挖的排水沟道中构建生态过水堰的试验装置,然后在静态条件下采用正交试验,以CODct、TN、NH4+-N、NO3--N、TP的去除率为考察指标,将过水堰的槽长A、砂石粒径B、填充率C、填充物D作为4个影响因素,分析过水堰对农业废水中氮、磷污染物的截留去除机理,探讨影响过水堰净化能力的主要因素及最优水平组合。本次试验结果表明:生态过水堰对氮、磷污染物具有较好的截留去除能力,沟道中的污染物浓度随着水力停留时间而降低。对正交试验结果运用极差分析、方差分析、矩阵分析法,得出砂石粒径B对过水堰净化农田污水的影响最大,各影响因素主次顺序为砂石粒径B填充率C填充物D槽长A,生态过水堰对污染物去除率较好的最优水平组合为A3B1C3D1,即槽长3m,砂石粒径0.8～1.2mm,填充率为65%的竹片。因此在白马湖周边的农田排水沟道中构建生态过水堰,可以有效拦截农田流失的养分和减少农田氮、磷污染物质向下游水体扩散迁移,同时本文研究结果为生态过水堰在农村地区的推广应用提供了理论依据和技术支撑。
[Abstract]:In recent years, agricultural non-point source pollution in the surrounding area of Baima Lake has become increasingly serious. The nitrogen and phosphorus pollutants contained in it have entered the atmosphere, soil and water body, which have caused serious damage to the water environment and ecosystem. According to field investigation, the sources of agricultural non-point pollution mainly include planting, breeding, rural domestic sewage and so on. The occurrence and development of agricultural non-point pollution went through three stages: source-stream-sink. In view of these three stages, this paper puts forward the source control technology of non-point source pollution, the interception control technology in the process of pollutant transfer to the nearby water body, and the terminal sewage purification technology. The Baima Lake Basin is a rice growing area, where irrigation channels and drainage channels are crisscrossed. As the initial gathering place of agricultural and rural domestic sewage, drainage channel is the passage of agricultural non-point source pollutants into the river. Therefore, the study of nitrogen and phosphorus transport and transformation in channel system is the key to control and control non-point source pollution in farmland. In order to effectively control nitrogen loss from farmland soil, phosphorus pollutants enter the surrounding water body through drainage channel. Based on the summary of non-point source pollution control technology at home and abroad, a new ecological overwater Weir in farmland drainage ditch is designed in this paper. On the premise of not affecting the daily drainage of farmland channel, the sewage can be intercepted and purified, and the land use area can be reduced. In this paper, the experimental equipment of ecological overwater Weir is constructed in the artificially excavated drain channel, and then the orthogonal test under static condition is used to study the removal rate of CODcttTTNNH4-NNNCONNO3 NITP. The removal mechanism of nitrogen and phosphorus pollutants in agricultural wastewater was analyzed by taking the channel length A, sand particle size B, filling ratio C and filler D as four influencing factors. This paper discusses the main factors affecting the purification capacity of overwater Weir and the optimal level combination. The results show that the ecological overwater Weir has a better ability to intercept and remove nitrogen and phosphorus pollutants, and the concentration of pollutants in the channel decreases with HRT. By means of range analysis, variance analysis and matrix analysis of orthogonal test results, it is concluded that sand particle size B has the greatest influence on the purification of farmland sewage by overwater Weir. The main and secondary influencing factors were sand diameter B filling rate C fill D slot length A, and the best level combination of A 3B 1C 3D 1 for ecological overwater Weir was A 3B 1C 3D 1, I. e., the length of the trough was 3 m, the diameter of sand and gravel was 0.81.2mm, and the filling rate was 65%. Therefore, the construction of ecological overwater Weir in the drainage channel around Baima Lake can effectively intercept the nutrient loss from farmland and reduce the nitrogen and phosphorus pollution from farmland to the downstream water body. At the same time, the research results provide theoretical basis and technical support for the extension and application of ecological overwater Weir in rural areas.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X71
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本文编号：2042342