不同植物篱系统对坡耕地农田径流污染物的去除研究

发布时间：2018-02-21 09:35

  本文关键词： 植物篱系统 坡耕地农田废水 地表径流 污染物 去除率　出处：《四川农业大学》2016年硕士论文　论文类型：学位论文

【摘要】：近年来,我国坡耕地对农药、化肥的有效使用率仅仅为30%,多数未被利用的农药、化肥随降雨或农业灌溉而形成农田废水,通过地表径流或地下渗漏等途径直接进入到地表水或地下水系统,从而导致水体污染。虽然我国采取多种措施减缓农田废水所带来的面源污染,但是农业面源污染所引起的流域水质恶化趋势并未得到根本改善,甚至部分湖、河水质状况堪忧。植物篱技术作为一种广泛应用于坡耕地与水环境之间的生态隔离措施,可以控制坡耕地农田废水中营养元素流失。本文选择四川常见且广泛用于生态环境修复、固土护坡、边坡绿化的3种植物为对象(红叶石楠、小叶女贞和黑麦草),构建植物篱系统。研究过程中,将三种植物进行混搭形成四种不同的植物篱系统(T1：红叶石楠+小叶女贞+黑麦草；T2：红叶石楠+小叶女贞；T3：小叶女贞+黑麦草；T4：红叶石楠+黑麦草)。本文首先通过正交实验来探讨植被条件、污染物进水浓度、降雨量、坡度4种因素对植物篱系统去除各种径流污染物的影响,并对各因素进行多元回归分析；其次,研究不同坡度和污染物进水浓度下,四种植物篱系统对坡耕地农田废水随地表径流流失的总氮(TN)、总磷(TP)、氨氮(NH3-N)、总有机碳(TOC)、化学需氧量(COD)的去除效果。研究结果如下：(1)正交实验结果表明,植被条件、污染物进水浓度、降雨量均对植物篱对TN的去除具有极显著影响,而坡度对TN的去除具有显著影响；植被条件、污染物进水浓度、坡度能极显著影响植物篱对TP和TOC的去除率,而降雨量的影响不显著；植被条件、降雨量和坡度对氨氮去除率具有极显著的影响,而污染物进水浓度对其有显著影响;四种因素对COD的去除率具有极显著的影响。多元回归分析表明,各因素间存在极显著的线性关系。(2)植物篱系统对农田废水中5种污染物的去除率均随坡度的增加而降低,其中TP、NH3-N、COD的去除率受坡度影响尤为明显。研究表明,当坡度由5°增加到20°时,TP的去除率由52.25%～76.75%降至33.68%-60.34%、NH3-N的去除率由36.84%～68.33%降至34.30%～45.46%、COD的去除率由13.26%～38.69%降至3.15%-26.74%；除NH3-N外,随着污染物进水浓度的升高,植物篱对其去除效果越明显。当进水水质从低浓度增加到高浓度时,TP的去除率可由33.33%～60.11%升至57.06%～81.44%、TOC的去除率可由-0.84%-2.92%升至9.64%～17.69%、COD的去除率可由-14.75%-11.25%升至20.62%～42.33%。(3)植物篱系统对TN、TP、NH3-N、TOC、COD的去除效果显著优于裸土。与裸土相比,在不同坡度下,以上5种污染物的去除率最高分别能由12.81%上升至47.02%、34.29%上升至76.75%、18.27%上升至68.33%、-0.93%上升至11.52%、2.31%上升至38.69%；在不同污染物进水浓度下,5种污染物的去除率最高分别能由15.57%升至53.05%、37.93%升至81.44%、17.60%升至64.05%、2.92%升至17.69%、-33.40%升至11.25%。(4)四种植物篱系统对模拟农田废水的平均去除效果由大到小依次为：T1T4T3T2,即红叶石楠+小叶女贞+黑麦草去除效果最佳。其主要原因在于,这三种植物的地表覆盖率高、根系发达,并且在去污功能上相互取长补短、协同固定污染物等性质密切相关。综上所述,红叶石楠、小叶女贞、黑麦草进行混搭后形成植物篱系统对坡耕地农田废水中的污染物去除效果显著,成本低廉、投入少、适用范围广。研究结果可以为坡耕地农业面源污染的控制、植物篱技术的推广和重点水源地的保护提供理论依据,为改善西南地区的水环境质量提供一条新思路。
[Abstract]:In recent years, China's sloping land of pesticides, effective fertilizer use rate of only 30%, most of the unused pesticides, fertilizers and the formation of agricultural wastewater with rainfall or irrigation, direct access to surface water or groundwater system through surface runoff or underground leakage pathways, resulting in water pollution. Although China has taken various the measures of non-point source pollution caused by slow agricultural wastewater, but the water quality of agricultural non-point source pollution caused by the deterioration of the trend has not been fundamentally improved, and even part of the lake, the water quality condition. Hedgerow technology is a widely used in slope land and water environment ecological isolation measures, can control the nutrient elements in sloping farmland water loss. This paper chooses Sichuan common and widely used in environmental remediation, soil protection, 3 species of green slope as the object (red Shi Nan, Ligustrum quihoui and ryegrass), The construction of Hedgerow System. In the course of the study, three kinds of plants are mixed to form four kinds of different Hedgerow System (T1: Photinia + Ligustrum quihoui + ryegrass; T2: Photinia + Ligustrum quihoui; T3: Ligustrum quihoui + ryegrass; T4: Photinia + ryegrass). This paper discusses the vegetation conditions by orthogonal firstly, the influent concentration of pollutants, pollutant removal effect of rainfall runoff on various hedgerow slope system of 4 kinds of factors, and the factors for multiple regression analysis; secondly, on different slope and pollutant influent concentration, four kinds of Hedgerow System with total nitrogen loss by runoff on sloping farmland wastewater (TN) (TP), ammonia nitrogen, total phosphorus (NH3-N), total organic carbon (TOC), chemical oxygen demand (COD) removal. The results are as follows: (1) the experimental results showed that the vegetation condition, the influent concentration of pollutants, and rainfall Physical fence had significant effects on the removal of TN, and the slope has a significant impact on the removal of TN; vegetation conditions, pollutant concentration, slope can significantly influence the hedgerow on TP and the removal rate of TOC, but not significantly influenced by precipitation; vegetation, rainfall and slope rate has significant effect on ammonia nitrogen the removal of pollutants, and the influent concentration has a significant effect on the four factors; the removal rate of COD has significant effect. Multiple regression analysis showed that there existed extremely significant linear relationships between various factors. (2) the Hedgerow System of 5 kinds of pollutants in agricultural wastewater removal rate decreased with the increase of slope among them, TP, NH3-N, COD removal rate is affected by slope has obvious effect. The results show that when the slope increased from 5 degrees to 20 degrees, the removal rate of TP from 52.25% to 76.75% to 33.68%-60.34%, the removal rate of NH3-N from 36.84% to 68.33% to 34.30% To 45.46%, the removal rate of COD from 13.26% to 38.69% to 3.15%-26.74%; in addition to NH3-N, with the increase of pollutant concentration, hedgerows on the removal effect is more obvious. When the influent water increased from low concentration to high concentration, the removal rate of TP from 33.33% ~ 60.11% to 57.06% ~ 81.44%, the removal rate of TOC from -0.84%-2.92% to 9.64% ~ 17.69%, the removal rate of COD from -14.75%-11.25% to 42.33%. (20.62% ~ 3) Hedgerow System on TN, TP, NH3-N, TOC, the removal rate of COD was significantly higher than that of bare soil. Compared with bare soil, under different slope, with 5 kinds of pollutants on the highest removal rate can respectively. Increased from 12.81% to 47.02%, 34.29% up to 76.75%, 18.27% up to 68.33%, -0.93% increased to 11.52%, rising to 2.31% in 38.69%; different pollutants influent concentration, 5 kinds of pollutants removal rate respectively rose from 15.57% to 53.05%, 37.93% to 81.44 %,17.60%鍗囪嚦64.05%,2.92%鍗囪嚦17.69%,-33.40%鍗囪嚦11.25%.(4)鍥涚妞嶇墿绡辩郴缁熷妯℃嫙鍐滅敯搴熸按鐨勫钩鍧囧幓闄ゆ晥鏋滅敱澶у埌灏忎緷娆′负锛歍1T4T3T2,鍗崇孩鍙剁煶妤，

本文编号：1521614