水培蔬菜系统对农村生活污水尾水中氮磷去除及资源化利用研究

发布时间：2018-11-17 18:45

【摘要】：针对农村生活污水尾水中氮磷浓度较高及有机物浓度较低等特点,本文开展水培蔬菜与潜流式人工湿地不同组合工艺净化生活污水尾水的研究,考察系统运行的工艺特性,优化运行参数,解析系统内污染物去除途径及机理,实现氮磷资源最大化利用,并对蔬菜进行食用安全性评价。主要研究成果如下：(1)随着水力负荷的增加,水培蔬菜系统、水培蔬菜系统／潜流式人工湿地、潜流式人工湿地／水培蔬菜系统和潜流式人工湿地等四种工艺系统对污染物的去除率均逐渐降低,为实现氮磷最大化利用并保证出水能够达到一级A排放标准(GB18918-2002),水培蔬菜系统、水培蔬菜系统／潜流式人工湿地组合工艺的适宜水力负荷为分别0.2 m3/(m2·d)和0.3 m3/(m2·d)。(2)水培蔬菜系统内空心菜采用1/4收割方式时,一方面能够保证系统净化效果的稳定性；另一方面空心菜的产量分别是全收割方式和1/2收割方式的1.3倍和1.1倍。(3)定量分析水培蔬菜系统内不同形态氮及磷的去除途径,结果表明在去除NH4-N的过程中,空心菜吸收、硝化作用以及氨挥发作用的贡献率分别为37.62%、58.86%、3.52%;在去除NOX--N的过程中,空心菜吸收、反硝化作用的贡献率分别为56.33%、43.67%；在去除TN的过程中,空心菜吸收、反硝化作用、氨挥发作用贡献率分别为47.68～59.57%、39.43～51.34及1%；在去除TP的过程中,空心菜吸收及其他途径的贡献率分别为58.38～77.48%和22.51～41.62%;可以看出,空心菜吸收是水培蔬菜系统氮磷去除的主要途径。(4)对生活污水尾水水质进行监测,重金属汞和石油类有时会超标,其它指标均符合农业灌溉水质标准；同时对水培蔬菜系统内冬季种植的水芹菜和夏季种植的空心菜进行食用安全性评价,结果表明蔬菜内重金属铅有时会超标,其它指标均符合无公害产品标准。综上所述,采用水培蔬菜系统／潜流式人工湿地组合工艺净化农村生活污水尾水时,在保证污水达标的同时,可实现尾水氮磷资源最大化利用,将污水治理和农业生产有机结合。
[Abstract]:In view of the characteristics of high concentration of nitrogen and phosphorus and low concentration of organic matter in rural domestic sewage tailwater, this paper carried out a study on the purification of domestic sewage tailings by different combination processes of hydroponic vegetables and subsurface flow constructed wetland, and investigated the technological characteristics of the system operation. The operating parameters were optimized, the ways and mechanisms of pollutant removal in the system were analyzed, the utilization of nitrogen and phosphorus resources was maximized, and the edible safety of vegetables was evaluated. The main results are as follows: (1) with the increase of hydraulic load, hydroponic vegetable system / subsurface flow constructed wetland, In order to maximize the utilization of nitrogen and phosphorus and to ensure that the effluent can meet the first class A discharge standard (GB18918-2002), the removal rate of pollutants in the four process systems of subsurface constructed wetland / hydroponic vegetable system and subsurface flow constructed wetland is gradually reduced. Hydroponic vegetable system, The suitable hydraulic load of hydroponic vegetable system / subsurface flow constructed wetland was 0.2 m3 / (m2 d) and 0.3 m3 / (m2 d). (2) respectively. On the one hand, it can ensure the stability of the purification effect of the system; On the other hand, the yield of hollow vegetables was 1.3 times and 1.1 times as much as that of total harvesting and 1 / 2 harvesting, respectively. (3) quantitative analysis of nitrogen and phosphorus removal pathways of different forms in hydroponic vegetable system. The results showed that the contribution rates of absorption, nitrification and ammonia volatilization were 37.62%, 58.86% and 3.52%, respectively. In the process of NOX--N removal, the contribution rates of the absorption and denitrification were 56.33 and 43.67, respectively. In the process of TN removal, the contribution rates of absorption, denitrification and ammonia volatilization were 47.68 ~ 59.57 ~ 39.43 ~ 51.34 and 1 respectively. In the process of removing TP, the contribution rates of the absorption and other ways were 58.38% 77.48% and 22.51% 41.62%, respectively. It can be seen that the absorption of hollow vegetables is the main way to remove nitrogen and phosphorus in hydroponic vegetable system. (4) monitoring the water quality of domestic sewage tailings, the heavy metal mercury and petroleum sometimes exceed the standard, and other indexes all accord with the water quality standard of agricultural irrigation; At the same time, the edible safety of water celery grown in winter and hollow vegetables planted in summer were evaluated. The results showed that the heavy metal lead in vegetables sometimes exceeded the standard, and the other indexes were in line with the standard of pollution-free products. To sum up, when using the combination process of hydroponic vegetable system / subsurface flow constructed wetland to purify rural domestic sewage tailings, the maximum utilization of nitrogen and phosphorus resources in tail water can be realized while the sewage is up to standard. Organic combination of sewage treatment and agricultural production.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X799.3

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