平原地区农村中小河道生态修复技术集成研究

发布时间：2018-07-27 21:12

【摘要】：平原地区农村河道尤其是中小河道、毛细管河道因人类生产、生活的影响,自然生态遭到破坏,造成很多负面影响,突出表现在水质严重污染、水量衰减甚至干涸、河床的结构和稳定性下降、滨河带的生态功能退化、河流生境多样性及生物多样性显著下降、洪涝隐患严重等方面。农村河道生态环境问题的不容乐观,加之人们生活水平的提高,居民对河道的整治要求越来越高,迫切需要加大农村河道综合整治力度,从而改善生活环境。本文选取典型性的镇域作为研究区域,运用AHP-综合指数评价法构建了以自然结构健康、生态系统健康、社会服务状况为准则层的平原地区农村中小河道诊断体系,并对苏州地区农村中小河道生态问题进行了诊断,根据诊断的结果,提出生态护岸、生态浮床、生态湿地、底泥疏浚、生态补水、沟通水系等生态修复技术,并通过室内试验,从水质理化指标、各污染物的降解系数及浮游生物量三个方面对各生态修复技术的特点进行研究分析,以此为基础拟定各生态修复方案,如生态补水、沟通水系及各生态修复技术的联合方案等,并对修复后的效果进行预测和评价。论文的主要结论如下:(1)在构建的平原地区农村中小河道诊断体系中,准则层中生态系统健康、指标层中河道生态需水保证率所占的权重最大;河道渠化程度、珍稀水生物存活状况、水资源开发利用率、水景观舒适度处于病态水平;苏州地区农村中小河道健康总体水平处于亚健康-健康之间,其中自然结构健康、生态系统健康、社会服务状况分别处于病态-亚健康、亚健康-健康、亚健康-健康水平。(2)从水质的理化指标来看,各代表河段水体的COD和BOD5分别处于25~40mg/L和4.0~9.0mg/L之间,且未治理㧐砌块护岸㧐生态护岸㧐底泥疏浚㧐生态浮床㧐生态湿地;DO处于2.0~6.0mg/L之间,且生态湿地≈生态浮床㧐底泥疏浚㧐生态护岸≈砌块护岸㧐未治理;NH3-N、TP、TU分别处于0.6~2.4mg/L、0.10~0.35mg/L和5.0~56.0NTU之间,且未治理㧐砌块护岸㧐生态护岸㧐生态浮床㧐生态湿地㧐底泥疏浚。(3)从污染物的降解系数来看,各代表河段水体的KCOD:生态湿地㧐生态浮床㧐生态护岸㧐未治理㧐砌块护岸㧐底泥疏浚;KBOD5:生态湿地㧐生态浮床㧐生态护岸㧐未治理㧐砌块护岸㧐底泥疏浚;KNH3-N:生态湿地㧐生态护岸㧐生态浮床㧐砌块护岸㧐底泥疏浚㧐未治理;KTP:生态湿地㧐生态浮床㧐底泥疏浚㧐生态护岸㧐砌块护岸㧐未治理。(4)从浮游生物量来看,代表河段水体的浮游生物种群类别数:生态浮床㧐木桩+自然护岸㧐生态护岸㧐砌块护岸㧐底泥疏浚;浮游生物密度:木桩+自然护坡㧐生态浮床㧐生态护岸㧐砌块护岸㧐底泥疏浚;Margalef多样性指数:生态浮床㧐木桩+自然护岸㧐生态护岸㧐砌块护岸㧐底泥疏浚。(5)生态补水方案中,河道断面距补水口的距离、补水的时间、补水的水流方向、补水流量、补水口位置以及补水口的个数对水体的代谢率都有一定的影响。其中,以尧太河闸为补水口,5m3/s为补水规模(方案1-3)和以石路浜闸、尧太河闸为补水口,2 m3/s和3 m3/s为补水规模(方案3-7),在补水20h的水体平均代谢率分别为46.3%和51.3%,在补水80h的水体平均代谢率分别为96.9%和97.7%。(6)水系沟通前后各断面水体的代谢情况有所不同,水系规划后河网的整体代谢率高于规划前,且水系规划前断头浜的滞水区更多,污染物浓度高的区域更多。如以尧太河闸为补水口,5 m3/s为补水规模时,水系规划前和水系规划后在补水20h的水体平均代谢率分别为46.3%和38.1%(7)研究区域河道的最小生态需水量和生态流速分别在1.41~4.05m3/s、0.40~0.54m/s之间;以石路浜闸、尧太河闸和马庄港闸为补水口,补水流量都为3m3/s时,河网水体流量和流速的平均值分别为1.76m3/s、0.47m/s,满足河道的生态需求,对改善河网的水动力及生态需水量具有良好的效果。根据各补水方案的流量和流速结果,建议在选取生态补水方案时,可从多个补水口补水,使河网各个区域的河道都达到最小需水量,而补水流量不宜过大。(8)考虑到各生态修复技术的互补性,采用各生态修复技术联合方案,修复9个月后,与前一年相比,采用生态护岸+底泥疏浚联合修复方案后,整个修复过程中的COD平均值下降14.6%,DO上升26.1%,BOD5下降21.5%,NH3-N下降18.6%;采用生态湿地+木桩+自然护坡联合修复方案后,整个修复过程中的COD平均值下降23.9%,DO上升44.1%,BOD5下降26.6%,NH3-N下降20.4%;而采用生态湿地+木桩+自然护坡联合修复方案的治理效果最佳,整个修复过程中的COD平均值下降23.9%,DO上升44.1%,BOD5下降26.6%,NH3-N下降20.4%。
[Abstract]:The river channel in the plain area is especially the small and medium river. The capillary channel is destroyed by human production and life, and the natural ecology is destroyed. It has many negative effects. It is manifested in the serious pollution of the water, the attenuation of water and even the dry, the decline of the structure and stability of the riverbed, the degradation of the ecological function of the riverside zone, the diversity of river habitats and the living things. The ecological environment of the rural river is not optimistic, and the ecological environment of the rural river is not optimistic. In addition, the improvement of the living standard of the people, the improvement of the river is more and more demanding, and the comprehensive renovation of the rural river is urgently needed to improve the living environment. This paper selects the typical area as the research area. The AHP- comprehensive index evaluation method was used to construct the diagnosis system of small and medium river channel in plain area, which was based on natural structure health, ecosystem health and social service status. The ecological problems of small and medium river channels in Suzhou were diagnosed. According to the results of the diagnosis, the ecological bank, ecological floating bed, ecological wetland and sediment dredging were put forward. Ecological remediation technologies such as ecological water supplement and water system, and the characteristics of ecological remediation technologies are studied and analyzed from three aspects of the physical and chemical indexes of water quality, the degradation coefficient of each pollutant and the amount of plankton. On the basis of this, the ecological remediation schemes, such as ecological water supplement, communication water system and various ecological restoration techniques, are drawn up. The main conclusions of the paper are as follows: (1) in the rural middle and small river diagnosis system in the plain area, the ecological system is healthy in the standard layer and the weight of the ecological water requirement of the river channel is the largest in the index layer; the degree of channel channelization, the living condition of rare water biology, and the water resources The development utilization rate, the water landscape comfort level is in the morbid level; the overall level of health of the small and medium river channels in the rural areas of Suzhou is between subhealth and health, of which the natural structure is healthy, the ecosystem is healthy, the social service condition is in the morbid subhealth, subhealth health and subhealth health level. (2) from the physical and chemical indexes of water quality, each of them The COD and BOD5 representing the water body of the river section are between 25~40mg/L and 4.0~9.0mg/L, respectively, and are not treated? Block bank protection, ecological revetment, sediment dredging, ecological floating bed, ecological wetland, DO between 2.0~6.0mg/L, ecological floating bed, sediment dredging, ecological revetment and non control; NH3-N, TP, TU are in 0.6~2.4mg/L, 0.10~, respectively. Between 0.35mg/L and 5.0~56.0NTU, and untreated? Block bank protection, ecological revetment, ecological floating bed, ecological wetland? Sediment dredging. (3) from the degradation coefficient of pollutants, the ecological wetland of each representative River, ecological floating bed, ecological revetment, untreated, block bank, sediment dredging, KBOD5: ecological wetland, ecological floating bed, ecological revetment, and untreated KNH3-N: ecological wetland? Ecological wetland? Ecological revetment? Ecological floating bed? Block bank? Bottom mud dredging? No control; KTP: ecological wetland? Ecological floating bed? Sediment dredging? Ecological revetment? Block bank protection. (4) plankton population category representing river water: ecological floating bed, wooden pile + natural protection Shore? Ecological revetment? Block revetment? Sediment dredging; plankton density: wood pile + natural slope protection? Ecological floating bed? Ecological revetment? Block bank? Sediment dredging; Margalef diversity index: ecological floating bed? Wood pile + natural revetment? Ecological revetment? Block bank? Sediment dredging. (5) the distance from the channel section to the water supplement. Time, water flow direction, water supplement flow, water filling port position and the number of water supplement have a certain influence on the metabolic rate of water body. Among them, the Yao Tai River sluice is used as water supplement, 5m3/s is the water supplement scale (scheme 1-3) and the stone road sluice, the Yao Tai River Gate is the water supplement port, 2 m3/s and 3 m3/s are the water supplement scale (scheme 3-7), and the water replenishing water body is in the water body. The average metabolic rates were 46.3% and 51.3% respectively. The metabolic rate of the average metabolic rate in the water supplement 80h was 96.9% and 97.7%. (6), respectively. The overall metabolic rate of the river network was higher than that before the water system planning. The average metabolic rate of the water system before and after the planning of the water system was 46.3% and 38.1% (7), respectively, when the Yoda river gate was used as a replenishment port and 5 m3/s as a supplement of water. The minimum ecological water demand and the ecological flow rate of the river channel were between 1.41~4.05m3/s and 0.40~0.54m/s, respectively, and the water supplement of the stone road sluice, the Yao Tai River Sluice and the Ma Zhuang Gangzha were supplemented with water. When the flow rate of water is 3m3/s, the average value of flow and flow rate of river network is 1.76m3/s, 0.47m/s, which meets the ecological demand of the river. It has good effect on improving the hydrodynamic and ecological water requirement of the river network. According to the results of the flow and flow rate of the water supplement scheme, it is suggested that the water supplement can be supplementing from multiple water filling ports when the water supplement scheme is selected. Water can make the river course of each area of the river network reach the minimum water requirement, and the flow rate should not be too large. (8) considering the complementation of the ecological restoration technology, the COD average value of the whole restoration process is compared to the previous year after 9 months of restoration of ecological restoration and dredging, compared with the previous year. The decrease of 14.6%, DO rise 26.1%, BOD5 decline 21.5%, and NH3-N drop 18.6%. After the combined restoration scheme of ecological wetland + pile + natural slope protection, the average value of COD in the whole restoration process is 23.9%, DO rises 44.1%, BOD5 is 26.6%, NH3-N decreases 20.4%, and the treatment effect of ecological wetland + wooden pile + natural slope protection scheme is the best treatment effect, and the best treatment effect, the whole treatment effect of ecological wetland + wooden pile + natural slope protection combined restoration scheme is the best. During the repair process, the average COD decreased by 23.9%, DO increased by 44.1%, BOD5 decreased by 26.6%, NH3-N decreased by 20.4%.
【学位授予单位】：苏州科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV85

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