雨水滤清系统不同设施对水质的净化效果研究

发布时间：2018-04-08 16:00

本文选题：植被过滤带　切入点：滤清池　出处：《西北农林科技大学》2017年硕士论文

【摘要】：水土流失与水资源短缺并存是黄土高原地区制约经济社会发展的主要矛盾之一。由于黄土高原地区干旱少雨,雨季土壤养分流失严重,加之劣质水分布较广,发展节水高效农业缺乏适宜的灌溉用水。同时,部分农村地区饮水安全问题突出,利用雨水就是黄土高原许多地区发展节水农业和解决饮用水安全的重要途径。不同蓄水设施对水质的影响不同,进而可能对居民的身体健康有不同程度的影响。本研究针对黄土高原水土流失、灌溉用水及饮用水短缺等问题,基于调控降雨径流、高效利用水土资源的理念,通过室内及野外试验,进一步研究了雨水滤清系统的不同组成设施对水质的净化作用。室内试验研究了能源型牧草柳枝稷在不同坡度和不同降雨条件下对地表径流及养分的拦截作用;野外试验研究了砾石滤清渠道、砾石滤清池及蓄水设施对水质的影响。取得的主要结论如下:(1)坡度对柳枝稷过滤带地表径流及养分的拦截效率影响:基于设计的5°,10°和15°坡度条件下的降雨试验(每场降雨的雨强均为0.8 mm/min、降雨量均为72 mm),研究结果表明,随着坡度的增大,宽度为1 m的柳枝稷过滤带对地表径流和非吸附性养分NO3-N的拦截效率降低,对吸附性养分NH3-N和TP拦截效率的变化规律与NO3-N不同。在5°,10°和15°条件下,柳枝稷过滤带对径流的拦截率分别为33.0%,28.7%和25.2%;对径流中硝态氮的拦截率分别为42.6%,36.1%和29.1%;对径流中铵态氮的拦截率分别为42.5%,44.0%和51%;对径流中总磷的拦截率分别为43.3%,61.5%和44.2%。(2)柳枝稷过滤带在间歇性降雨条件下对地表径流及养分的拦截效率呈现一定规律。在雨强依次为0.8 mm/min,1.2 mm/min和1.8 mm/min的间歇性降雨事件中(每场降雨的坡度均设为15°、降雨量均为72 mm,降雨间隔时间为24 h),宽度为1 m的柳枝稷过滤带对地表径流、径流中无机氮(硝态氮和铵态氮之和)及径流中总磷的拦截效率随降雨场次的增加而降低。柳枝稷过滤带对径流的拦截率分别为25.2%,15.7%和12.0%;对径流中硝态氮的拦截效率分别为29.1%,25.0%和15.3%;对径流中铵态氮的拦截效率分别为51.0%,55.9%和32.4%;对径流中总磷的拦截效率分别为44.2%,36.0%和27.8%。(3)柳枝稷过滤带能够有效增加降水入渗和养分入渗,从而将养分拦蓄在土壤中,降低地表流失量。在5°,10°和15°条件下,柳枝稷过滤带降水平均入渗速率是对应裸坡平均入渗速率的1.3,1.5和1.7倍。柳枝稷过滤带土壤水中的养分含量高于裸坡:硝态氮含量是裸坡的1.6~2.4倍,铵态氮含量是裸坡的2.2~3.8倍,总磷含量是裸坡的3.3倍左右。在雨强增大的间歇性降雨条件下,柳枝稷过滤带在前期和中期降雨中能够通过入渗有效地拦蓄氮磷营养物质,而到后期降雨中,柳枝稷过滤带通过入渗拦蓄养分的效率降低。同时,柳枝稷过滤带土壤水中养分的累积过程呈现一定的规律。中期降雨事件中硝态氮和总磷累积量的变化过程同时包含前期降雨和后期降雨的特征,是一个过渡期:均在降雨50 min出现转折点,降雨50min之前的增长趋势和增长速率同前期降雨类似,而降雨50 min之后的增长趋势和增长速率则同后期降雨类似,入渗水量是这种特征的决定性因素。(4)砾石滤清渠道及滤清池对水质有明显的净化作用;不同材质的蓄水设施对水质的影响不同。砾石滤清渠道及滤清池能够有效降低水中的浊度、COD、氮及硫酸盐水平,同时能够消减水中理化指标的峰值,并使其快速达到稳定。砾石渠道在沿程19 m处对浊度、COD和NO2-N的净化程度达到最大,之后逐渐稳定;TN和SO42-浓度在10 m~19 m之间基本保持稳定,在19 m~28 m之间有所下降。建议在砂石料丰富的地区采用简易的砾石滤清渠道和滤清池,从而为高效农业灌溉及居民生活提供清洁用水,成本较低且简便易行。不同材质的蓄水设施对水质的影响作用不同:在相同的集雨面条件下,混合窖(水泥砂浆抹面,窖底铺胶泥)的水质总体优于水泥窖;以公路面为集雨面的胶泥窖水质较差。建议不要使用公路集雨面收集的雨水作饮用水;在有条件的情况下尽量不要采用纯水泥窖,可在水泥窖底部铺一层胶泥,以便更有效地吸附、沉淀杂质,从而提高水质净化效率。综合考虑水质状况、水窖的建造成本以及环境友好性,干硬性固化土水窖是一种净化水质效果较好的水窖形式。
[Abstract]:Soil erosion and water resource shortage is one of the main contradiction of restricting economic and social development of the Loess Plateau. Because of the drought in the Loess Plateau and little rain, the rainy season soil nutrient loss, coupled with poor quality water is widely distributed, the development of water-saving agriculture lacks the suitable irrigation water. At the same time, the safety of drinking water in rural areas, some problems, an important way the development of water-saving agriculture in many areas of the Loess Plateau is the use of rainwater and solve the safety of drinking water. The influence of different storage facilities for water quality is different, which may have different effects on the health of the residents. The study on soil erosion in the Loess Plateau, the problem of irrigation water and drinking water shortage, rainfall runoff regulation based on efficient utilization of water and soil the idea of resources, through indoor and field experiments, further studies on water purification of different facilities rainwater filtration system The role of laboratory experiments. The interception effect of energy forage switchgrass on runoff and nutrient in different slope and different rainfall conditions; field experiment was conducted to study the effects of gravel gravel filter channels, filtration pool and water storage facilities for water quality. The main conclusions are as follows: (1) the slope effect on switchgrass filter surface runoff and nutrient interception efficiency: Design Based on 5 degrees, 10 degrees and 15 degrees rainfall slope conditions (each rainfall rainfall intensity was 0.8 mm/min, the rainfall was 72 mm), the results show that with the increase of slope, width of switchgrass filtration of 1 m with the interception efficiency of NO3-N the surface runoff and non nutrient adsorption decreased, adsorption of NH3-N and different nutrient variation of TP and NO3-N. The interception efficiency at 5 degrees, 10 degrees and 15 degrees under the conditions of switchgrass filter strips on runoff interception rates were 33%, 28.7% and 25.2%; the Nitrate nitrogen in runoff interception rate were 42.6%, 36.1% and 29.1%; the ammonium nitrogen in runoff interception rate were 42.5%, 44% and 51%; the total phosphorus in runoff interception rate were 43.3%, 61.5% and 44.2%. (2) with intermittent filtration of switchgrass under the condition of rainfall interception efficiency of runoff and the nutrients show a certain regularity. The rainfall intensity was 0.8 mm/min, 1.2 mm/min and 1.8 intermittent rainfall events in mm/min (each rainfall gradient was set at 15 degrees, the rainfall was 72 mm, the time interval of rainfall is 24 h), the width is 1 m with switchgrass filtration of surface runoff, inorganic in the runoff of nitrogen (nitrate nitrogen and ammonium nitrogen and total phosphorus) and interception efficiency in runoff decreased with increasing rainfall. Switchgrass filter strips on runoff interception rates were 25.2%, 15.7% and 12%; the interception efficiency of nitrate nitrogen in runoff were 29.1%, 25% and 15.3%; the size Flow interception efficiency of ammonium nitrogen were 51%, 55.9% and 32.4%; the interception efficiency of total phosphorus in runoff were 44.2%, 36% and 27.8%. (3) switchgrass filter strips can effectively increase the precipitation infiltration and infiltration of nutrients, which will retain the nutrients in the soil, reduce the surface loss at 5 degrees., 10 degrees and 15 degrees under the conditions of switchgrass filtration with precipitation average infiltration rate is corresponding to bare slope average infiltration rate of 1.3,1.5 and 1.7 times. Switchgrass filter belt soil water nutrient content is higher than that of the bare slope, the content of nitrate nitrogen is 1.6~2.4 times higher than the bare slope, the content of ammonium nitrogen is 2.2~3.8 times of bare the slope, the total phosphorus content is about 3.3 times of bare slope. In the intermittent rainfall rain intensity increased, switchgrass infiltration through filtering belt can effectively retain the nitrogen and phosphorus nutrients in the early and mid and late rain, rain, switchgrass filtered by infiltration stopped keeper sub. The rate of decrease. At the same time, the accumulation process of switchgrass with soil nutrient water filtration showed a certain pattern. The characteristics of medium term accumulation of nitrate and total phosphorus in the amount of rainfall events change process also includes the early rainfall and late rainfall, is a transitional period: 50 min rainfall appeared at the turning point, before the rainfall 50min the growth trend and growth rate with similar rainfall and antecedent rainfall, after 50 min growth trend and growth rate with late rainfall is similar to that of infiltration of water is the decisive factor for this feature. (4) gravel filtration and filtration channels pool is obviously purify the water quality; influence of water storage facilities of different materials on the different water quality filtration and filtration pool. Gravel channels can effectively reduce the water turbidity, COD, nitrogen and sulfate levels, and can reduce peak water physicochemical index, and make it fast to achieve stability. Along the gravel channel 19 m of turbidity, COD and NO2-N purification degree reached the maximum, then gradually stabilized; TN and SO42- concentrations between 10 m~19 m remained stable, declined between 19 m~28 m. By simple filtration and filtration pool in the gravel channel sand rich area, and to provide clean water from efficient irrigation and living, low cost and convenient storage facilities. The different material effect on water quality of Different Rainfall Collecting: in the same conditions, the mixed pit (cement mortar, cement pit bottom shop) the overall water quality is better than that of cement kiln; with the road surface for collecting rain water of the clay pit poor. Not recommended for drinking water in road surface to collect rain rain; in the case of conditions as far as possible not to use the pure water mud pit, can lay a layer of clay in cement pit bottom for more effective adsorption, precipitation of impurities, so as to improve the The water purification efficiency. Considering the water quality, water cellar construction cost and environmental friendliness, dry curing soil water cellar is a kind of water purification effect good cellar form.

【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X52;S277.7

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