冬季浮床人工湿地对污水处理厂二级出水净化研究

发布时间：2017-12-26 20:05

本文关键词：冬季浮床人工湿地对污水处理厂二级出水净化研究　出处：《南京大学》2016年硕士论文　论文类型：学位论文

【摘要】：当前,人工湿地已被广泛用于污染处理厂出水的深度处理。然而,由于水生植物及微生物的活性与温度有显著关系,在高纬度地区或者冬季平均气温低于10℃的低中纬度地区去除污水中过量的营养物质仍然是一个挑战。人工湿地水生植物种类的选择被视为影响冬季湿地净化功能的因素之一,对于植物种类的选择已有大量研究。然而,很少有研究关注冷季型水生植物在冬季去除污水中营养物质中的重要性及其作用途径。不同季节污水处理厂的二级污水排放量一般相对恒定,为实现湿地出水水质的稳定达标,湿地也需要相对恒定的净化能力,那么提高湿地在冬季的污水处理效率具有特殊意义。本研究以水芹为浮床植物,通过建立三种类型的人工湿地系统：无浮床无植物系统(CK)、浮床无植物系统(FW)和浮床植物系统(FW-M),探究冬季水芹在污水处理厂二级出水处理下的生长动态和生理特征变化,冬季人工浮床湿地系统对污水处理厂二级出水污染物的去除及氮去除途径。通过对不同处理间和季节间净化能力差异进行单因素方差分析和双因素方差分析,得出以下主要结论：(1)实验期间,大气温度在-6.2℃和19.1℃之间波动,平均温度为6.2℃,而水温(距水面50厘米深度)在3.3℃和14.5℃间波动,平均温度为6.8℃。在第一个到第八个周期内的平均气温分别为11.9℃,9.45℃,11.1℃,3.25℃,2.30℃,3.85℃,3.60℃和4.70℃。基于气温标准,总体实验期可分为两个子阶段：前三个周期(秋季)和后五个周期(冬季)。(2)不同系统间电导率和TDS差异显著。在CK,FW和FW-M人工湿地平均PH分别为8.0,8.1和8.4,该值显示处理之间没有显著差异(p=0.236)。与CK(1.22毫秒/厘米,p=0.003)和FW(1.25毫秒/厘米,p=0.014)系统相比,FW-M处理有显著较低的电导率值(0.79毫秒/厘米)。FW和FW-M系统的TDS值分别为0.78,0.79和0.51g/L,它们之间具有显著的差别(p=0.006)。(3)冬季水芹在浮床人工湿地保持了相对较高的活性。在FW-M系统中,水芹的根长在前两个实验周期里迅速加长,由10月31日的7.8厘米长至11月20日的18.09厘米,在之后的六个实验周期里生长速度放缓。相似的是,地上部分的长度同样在前两个实验周期里迅速增长,从20.02厘米增长到25.15厘米,之后随着老叶的枯萎而有所降低。在整个实验期间,叶片的叶绿素含量逐渐降低,而根系活力在12月30日之前逐渐下降,随后略有增加。根系孔隙度和泌氧在深秋实验批次有所增加,进入冬季后开始下降。因此,在平均气温3.63℃的冬季,尽管冷季型植物水芹的叶片已经枯萎,但植物根依然能维持较高的活性。(4)生态浮床人工湿地可以有效地从尾水中去除氮和磷,但是COD的去除率较低。在实验期间,CK,FW,FW-M三个系统COD的平均去除率为8.13%,14.59%和18.53%,三组处理间COD的去除率无显著差异(p=0.437)。FW-M系统对TN, NO3--N, NH4+-N, TDN和TP的平均去除率为26.48%,36.18%,39.30%,26.23%和24.64%；FW系统对TN,N03--N,NH4+-N,TDN和TP的平均去除率为3.76%,14.77%,5.74%,5.55%和4.77%；CK系统对TN,N03--N,NH4+-N,TDN和TP的平均去除率为4.38%,2.91%,7.76%,3.96%和2.73%。FW-M在对TN,N03--N,NH4+-N,TDN和TP的平均去除率显著高于CK和FW,p值在0.002到0.016之间。(5)植物吸收氮的速率下降是导致冬季相比于秋季氮去除率下降的最主要的原因。FW-M系统中,植物吸收途径对氮的去除率急剧下降,从秋季的67.13 mgN·m-2·d-1下降到冬季的20.09 mg N·m-2·d-1,下降了70.07%。通过植物吸收途径去除氮占氮总去除量的比例从秋季的33.39%,下降至冬季的15.01%。微生物途径在秋季和冬季对氮的去除率分别为127.66 mg N·m-2·d-1和96.34 mgN·m-2·d-1,相比下降了24.53%。微生物途径去除在氮总去除率中所占的比例从秋季批次的63.50%增长到冬季批次的71.57%。
[Abstract]:At present, artificial wetland has been widely used for the treatment of effluent from pollution treatment plants. However, due to the significant relationship between the activity of aquatic plants and microbes and temperature, it is still a challenge to remove excess nutrients from sewage at high latitudes or low latitudes with mean temperature below 10 C in winter. The selection of aquatic plant species in artificial wetland is considered as one of the factors affecting the purification function of wetland in winter, and there has been a great deal of research on the selection of plant species. However, few studies have paid attention to the importance of cold season aquatic plants in the removal of nutrients from sewage in winter and their ways of action. In the different seasons, the two level sewage discharge of sewage treatment plants is generally relatively constant. In order to achieve stable target quality of wetland effluent, wetlands need relatively constant purification capacity, so improving the efficiency of wetland sewage treatment in winter is of special significance. In this study, cress as floating bed plants, the artificial wetland system to establish three types: free floating bed plant system (CK), floating bed plant system (FW) and floating bed plant system (FW-M), the dynamic growth and physiological characteristics of winter cress on changes in the sewage treatment plant effluent treatment under two the artificial floating bed system of nitrogen removal and wetland in winter two sewage treatment plant effluent pollutant removal pathways. According to the different treatments and seasonal differences of purification capacity variance analysis of single factor variance analysis and two factors, the main conclusions are as follows: (1) during the experiment, the atmospheric temperature fluctuates between -6.2 degrees and 19.1 degrees, the average temperature of 6.2 degrees, while the water temperature (above water depth of 50 cm) in the range of 3.3 DEG C and 14.5 degrees, the average temperature is 6.8 DEG C. The average temperature in the first to eighth cycles is 11.9, 9.45, 11.1, 3.25, 2.30, 3.85, 3.60, and 4.70. Based on the temperature standard, the overall experimental period can be divided into two sub stages: the first three cycles (fall) and the later five cycles (winter). (2) the difference of electrical conductivity and TDS between different systems was significant. In CK, FW and FW-M artificial wetlands, the average PH was 8.0,8.1 and 8.4 respectively, and there was no significant difference between the treatments (p=0.236). Compared with CK (1.22 MS / cm, p=0.003) and FW (1.25 MS / cm, p=0.014) systems, FW-M treatment has a significantly lower electrical conductivity (0.79 milliseconds / cm). The TDS values of FW and FW-M systems are 0.78,0.79 and 0.51g/L, respectively, and there are significant differences between them (p=0.006). (3) the winter cress has maintained a relatively high activity in the floating bed of artificial wetland. In the FW-M system, cress root length increases rapidly in the first two experimental period, from October 31st to November 20th of the 7.8 cm long 18.09 cm, six experimental period after the growth rate slowed down. Similarly, the length of the aboveground part also increased rapidly in the first two experimental periods, from 20.02 centimeters to 25.15 centimeters, and then decreased with the withering of old leaves. During the whole experiment, the chlorophyll content of the leaves decreased gradually, and the root activity decreased gradually before December 30th, and then increased slightly. The root porosity and oxygen secretion increased in the late autumn experiment, and began to decline after winter. Therefore, the average temperature of 3.63 degrees in winter, although cold season plant leaves cress have withered, but the plant roots can still maintain high activity. (4) ecological floating bed constructed wetland can effectively remove nitrogen and phosphorus from the tail water, but the removal rate of COD is low. During the experiment, the average removal rate of three systems, CK, FW and FW-M, was 8.13%, 14.59% and 18.53%. There was no significant difference in the removal rate of COD between the three groups (p=0.437). The FW-M system of TN, NO3--N, NH4+-N, TDN and TP average removal rate was 26.48%, 36.18%, 39.30%, 26.23% and 24.64%; FW system on TN, N03--N, NH4+-N, TDN and TP average removal rate was 3.76%, 14.77%, 5.74%, 5.55% and 4.77%; CK system on TN, N03--N, NH4+-N, TDN and the average removal rate of TP was 4.38%, 2.91%, 7.76%, 3.96% and 2.73%. The average removal rate of FW-M for TN, N03--N, NH4+-N, TDN and TP was significantly higher than that of CK and FW, and the p value was between 0.002 and 0.016. (5) the decrease in the rate of plant nitrogen absorption is the main reason for the decrease of nitrogen removal rate in winter compared to autumn. In the FW-M system, the nitrogen removal rate of plant absorption pathway declined sharply from 67.13 mgN m-2 D-1 in autumn to 20.09 mg in winter, N and m-2 D-1 decreased by 70.07%. The total removal of nitrogen by plant absorption was reduced from 33.39% in autumn to 15.01% in winter. The removal rates of nitrogen in autumn and winter were 127.66 mg N. M-2. D-1 and 96.34 mgN. M-2. D-1, respectively, with a decrease of 24.53%. The proportion of microbial pathway removal in total nitrogen removal rate increased from 63.50% in autumn batch to 71.57% in winter batch.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X703

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