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1.
污水人工湿地系统中有机物积累规律与堵塞机制的研究进展 总被引：23，自引：0，他引：23
论述了人工湿地系统中有机物积累规律、土壤堵塞机制以及避免系统堵塞的措施。最后探讨了人工湿地中有机物动态的研究发展方向。 相似文献
2.
本研究设置了基质正、反级配垂直流人工湿地,通过测定系统对CODCr、TN、TP、NH4＋-N等指标的去除效率、有效孔隙率和渗透系数的变化来比较两种级配方式下垂直流人工湿地净化效果和系统渗透性能。结果表明,两种级配方式下,垂直流湿地系统对污染物去除的综合效果优于单一粒径的无烟煤湿地系统;反级配系统在除磷方面存在优势,正级配系统在CODCr去除方面显著强于反级配系统,在脱氮方面两者不存在显著性差异;反级配系统的有效孔隙率在各层的降幅变化不大,而正级配系统表层及上层有效孔隙率的降幅显著大于中层和底层;正级配系统渗透系数的变化显著高于反级配系统,且出现了持续性表面滞水现象。以上结果均表明,反级配垂直流湿地系统可以在保证净化效率的同时,缓解湿地基质堵塞,有效延长基质的使用寿命。 相似文献
3.
同等条件下开展了3种不同类型人工湿地（垂直流、潜流和表面流人工之地）对洞庭湖水质净化效果的研究。结果表明:（1）洞庭湖水体中NH4+-N,TN,TP,高锰酸钾指数,BOD5和CODCr的进水浓度与3种不同类型人工湿地出水浓度季节变化规律保持一致,冬季明显高于夏季,洞庭湖进水中NH4+-N,TN,TP,高锰酸钾指数,BOD5和CODCr浓度均高于3种不同类型人工湿地出水浓度,相同时期,3种不同类型人工湿地出水水质NH4+-N,TN,TP,高锰酸钾指数、BOD5和CODCr浓度基本表现为表面流 > 潜流 > 垂直流;（2）3种类型人工湿地对TN,TP,高锰酸钾指数、BOD5和CODCr的去除率依次表现为垂直流 > 潜流 > 表面流,而对NH4+-N的去除率依次表现为垂直流 > 表面流 > 潜流,其中以BOD5的去除效果最好（去除率最高）,但3种类型人工湿地对BOD5的去除率差异均不显著（p > 0.05）;（3）3种类型人工湿地植物地上和地下生物量均表现为垂直流 > 潜流 > 表面流,差异均显著（p < 0.05）,垂直流人工湿地植被N含量、P含量、N积累量和P积累量均显著高于潜流和表面流（p < 0.05）;（4）3种不同类型人工湿地植物的N,P积累量分别与生物量、N含量、P含量均呈显著的线性关系（p < 0.01）,人工湿地植物生物量对N,P积累量的影响大于植物体内N,P含量的影响,可以通过生物量来评价人工湿地植物对N,P去除效果。 相似文献
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5.
为了避免或减少人工湿地处理厌氧发酵液发生堵塞,并提高系统处理效果,该试验将蚯蚓引入到垂直流湿地系统中,并与水平潜流湿地构成混流系统,用来处理厌氧发酵液。结果表明:采用蚯蚓垂直流湿地-水平潜流湿地混流系统处理厌氧发酵液,在进水平均有机负荷达1.82 kg/(m~2·d),水力负荷10、20 cm/d的条件下,对化学需氧量、总磷、总悬浮固体的去除率达到了90%以上,氨氮去除率达80%以上,总氮去除率也维持在60%以上。提高水力负荷对污染物的消减量更有优势,水平潜流湿地对总氮的消减优于蚯蚓生态湿地。2种水力负荷下,混流湿地出水化学需氧量、氨氮、总磷、总悬浮固体均能达到《畜禽养殖业污染物排放标准》要求。蚯蚓使混流系统对化学需氧量、氨氮、总凯氏氮的去除分别提高了2%、12%、4%,同时具有同步处理污水污泥,缓解湿地堵塞的效果,处理水质基本达标,处理污泥的成本也大大降低,因此具有很大应用潜力。 相似文献
6.
本研究对邛海湖湿地水生维管植物种类及分布状况进行了调查。结果表明,邛海湖湿地现有水生维管束植物77种,隶属于25科50属。其中,蕨类植物5种,隶属2科3属;被子植物72种,隶属23科47属。从植物生态类型和生活型方面来划分,邛海水生维管束植物可分为湖区水生维管植物、河口滩涂植物和湿生植物三种类型。它们主要分布在湖泊的北面、西面和南面。区系分析结果表明,邛海水生维管束植物共有7种分布类型,其中以世界性分布型植物种最多。邛海湿地自然着生的水生植物群落破坏严重,挺水植物以上群落基本消失,浮水植物和沉水植物分布区锐减,分布深度退缩,分布密度减小。针对邛海湿地水生维管束植物存在问题,笔者提出了相应的解决方法和建议。该研究为邛海湿地的恢复和重建提供了理论依据。 相似文献
7.
艾比湖退化湿地的生态恢复 总被引：6，自引：0，他引：6
精河入湖口是典型干旱区湖泊湿地,也是艾比湖湿地的重要组成部分。近50年来,由于人类活动及气候变化等多种因素影响,艾比湖湿地生态系统健康受到威胁,出现不同程度的退化。为改善和恢复生态环境,自2004年开始实施湿地恢复实验工程。选择未恢复区、恢复1年区、恢复3年区和恢复5年区,比较其水、浮游生物、植被、土壤及碳循环等生态特征,结合野外调查及试验数据分析,对其恢复状态进行监测和评价。结果显示,至2009年,试验区湿地水域面积比例增加,水质得到改善,植被群落呈正向演替,土壤达到中、轻度盐碱化土水平,水禽种类增加,生物多样性更加丰富,土壤呼吸速率随恢复时间延长而逐渐提高。由此表明,只要水源充足,精河入湖口退化湿地在恢复过程中经4～5年即可恢复到未退化状态,以恢复湿地水文条件为核心措施的湿地恢复方案具有可行性。研究对于干旱区其他类型湿地的恢复及生态功能的改善具有指导作用。 相似文献
8.
以石佛寺人工湿地为研究对象,通过对湿地内各项水体富营养指标监测数据的分析,研究人工湿地对辽河水中富营养物质的去除效果。结果表明:2009年石佛寺人工湿地建成以来,水库出口处水体富营养情况明显好于湿地建成前,其中DO含量明显增加,有机物CODMn,BOD5及营养盐NH3-N,TN和TP的含量有显著降低。辽河水流经湿地内部,部分时段水体中DO含量的变化率出现负值,但湿地出口处DO含量均达到7.0 mg/L以上;湿地对有机物及营养盐具有良好的去除效果,且去除效果在汛期好于非汛期,2009—2011年的去除率均达到正值,对有机物CODMn,BOD5的最大去除率分别可达到48.3%,65.8%,对营养盐NH3-N,TN和TP的最大去除率分别可达到78.1%,88.2%和72.0%;2012—2013年部分时段的去除率出现了负值,说明随着湿地运行时间的延长,植物死亡后的腐烂分解会导致富营养物质的二次释放。 相似文献
9.
闽江口湿地不同土地利用方式下表层土壤N,P,K含量研究 总被引：7，自引：1，他引：6
对闽江口鳝鱼滩原生芦苇沼泽湿地以及由其转变的其它不同土地利用类型(草地、滩涂养殖地、水田、弃耕地、池塘养殖地)的表层土壤N,P和K含量进行测定.并研究其分布规律.结果表明:芦苇湿地转变为草地、滩涂养殖地、水田、池塘养殖地后,N平均含量从1.73 g/kg分别下降到1.60.1.3,0.69.0.65 g/kg,土壤剖面N素含量受土壤有机碳含量影响,总体上呈现由上到下逐渐减少趋势,同时芦苇湿地开发利用后.土壤中的NO-3-N含量升高;6种类型土壤中P含量在0.44～0.90 g/kg之间,变异较小,P的水平、垂直分异规律与有机碳、N的分布基本一致;不同土地类型K含量在15.15～29.62 g/kg之间.普遍高于N,P的含量,芦苇湿地的泥炭土K索含量明显低于其它5种土壤的K含量.不同土地类型土壤K素在剖面的分布规律差异较大.相关分析表明,不同土地利用类型的不同土层中有机碳、N与P之间具有良好的相关性.说明三者具有相似的空间分布规律,而K与有机碳、N相关性差,表明K素具有不同于N,P的独特空间分布规律. 相似文献
10.
人工湿地系统在垃圾渗滤液处理中的应用 总被引：9，自引：1，他引：8
人工湿地是一种很有前途的废水处理方法,具有对污染物的去除能力强、基建和运行费用低、维护管理方便、耐冲击负荷能力强等优点。对人工湿地系统在垃圾渗滤液处理中的表现进行了分析,结果表明,其对有机物、氮磷和金属元素均具有较高的去除率,利用人工湿地处理垃圾渗滤液的方法具有广阔的应用前景。 相似文献
11.
Yang Wang Mingxin Huo Qi Li Wei Fan Jiakuan Yang Xiaochun Cui 《Journal of Soils and Sediments》2018,18(9):2980-2994
Purpose
Water from different sources generally contains different kinds of suspended particles, which introduces the challenge of how to control physical clogging during managed aquifer recharge (MAR). Suspended solid concentration (SS) and turbidity (NTU) are widely recognized as indicators of physical clogging potential. The aims of this study were to examine the degree of physical clogging caused by organic and inorganic suspended particles and elaborate the different mechanisms that controlled clogging under specific SS and NTU conditions.Materials and methods
Column experiments were performed by continuous suspended particle injection through a saturated porous medium under stable physicochemical and hydrodynamic conditions. Three sets of transport tests were carried out. One test was conducted with chlorinated-secondary wastewater (CSW), which SS was 17.59?±?0.44 mg L?1 corresponding to 3.09?±?0.05 NTU. The other two tests were silica-particle wastewater (SPW) with the same SS (1.73?±?0.03 NTU) and the same NTU (29.21?±?0.57 mg L?1 SS) as the CSW, abbreviated to SPW-SS and SPW-NTU, respectively. The particle breakthrough curves (BTCs), spatial deposition profiles, and variations in hydraulic conductivity were measured. The transport model, DLVO theory, and O’Melia and Ali clogging model were applied to explain the mechanisms of physical clogging in different systems.Results and discussion
The retention of inorganic particles was greater than that of organic particles; 56.02% of organic particles were retained in CSW, while 87.62 and 86.36% of inorganic particles were retained in SPW-SS and SPW-NTU, respectively. The distribution of organic particles was less uniform than that of inorganic particles. However, the variation of the relative hydraulic conductivity (K/K0) was more significant for organic particles than for inorganic particles, with decreased by just 1.80?±?0.64% in SPW-SS and 4.03?±?1.64% in SPW-NTU, but decreased by 85.86?±?1.22% in CSW. This study explained the results with the support of classical models and the DLVO theory. The physicochemical characteristics of suspended particles determined whether and how physical clogging occurred.Conclusions
Suspended particles with different properties follow different transport-deposition processes and have different tendencies to cause physical clogging. Especially for organic particles, clogging degree is quite noticeable. Our results imply that the same SS and NTU threshold values cannot be applied to different types of source water during recharge to prevent physical clogging, even in the same controlled environmental conditions. Physicochemical characteristics of suspended particles need to be considered when developing physical clogging indicators.12.
太湖地区农田生态环境中土壤饱和导水率研究 总被引：30，自引：2，他引：28
对太湖地区主要水稻土类型的饱和导水率进行了研究.结果表明,该土壤的饱和导水率变化于7.20×10-5～6.33×10-4 cm/s, 并随着深度的增加饱和导水率迅速下降;原状土和扰动土的饱和导水率相差很大, 土壤的质地、有机质含量、容重、孔隙度和结构系数等均对饱和导水率有一定的影响.原状土的饱和导水率能反映田间的实际情况, 对研究土壤水分平衡和水土保持有极其重要的意义. 而扰动土的饱和导水率只能作为一种农业工程的参考数据被运用. 相似文献
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再生水灌溉对农田土壤水流运动影响的研究进展 总被引：2，自引：1，他引：1
再生水灌溉农田既可节约宝贵的水资源、缓解农业用水紧缺,同时再生水中的多种营养元素和微量元素可促进作物生长、提高粮食产量。但再生水中的物质进入农田后将引起土壤孔隙结构、团聚体结构、黏粒分散特征和水土作用关系等一系列的变化,进而引起土壤入渗性能和导水性能的改变,增大环境污染风险。该文综述了再生水中的悬浮无机固体、大分子有机质、油脂、表面活性剂和盐分对农田土壤水流运动的影响及其作用机理,指出受灌农田土壤结构性质演化过程与驱动机制、受灌农田土壤与灌溉入渗水流之间的相互作用关系为该领域亟需开展的2个研究方向。文章对再生水农田灌溉制度制定、污染风险控制和生态环境保护均有参考价值。 相似文献
14.
硅藻土微孔陶瓷灌水器制备工艺优化 总被引：1，自引：4，他引：1
为解决现有微孔陶瓷灌水器制备成本较高、产品性能低下,不利于大面积推广和应用的问题,该文以黏土、硅藻土和硫酸钙为主要原料,探索一种微孔陶瓷灌水器的低成本制备工艺。分析了硅藻土掺量和烧结温度2个因素对微孔陶瓷线收缩率、开口孔隙率、维式硬度、渗透系数和微孔陶瓷灌水器流量的影响规律。以线收缩率、维氏硬度、开口孔隙率、渗透系数和流量为指标,优选出微孔陶瓷灌水器的最佳制备工艺。结果表明:硅藻土掺量增加,或烧结温度降低,会使得微孔陶瓷的线收缩率和维氏硬度降低,开口孔隙率和渗透系数增大,进而使得微孔陶瓷灌水器的流量增大。综合比较,1 075℃烧结的硅藻土掺量质量分数为15%的微孔陶瓷灌水器,线收缩率为4.9%、开口孔隙率为26.3%、维氏硬度为448 MPa,在10 k Pa的工作压力下流量为1.64 L/h,兼备良好的力学性能和水力性能,是制备微孔陶瓷灌水器的最佳工艺。该研究为微孔陶瓷灌水器的制备和性能优化提供了参考。 相似文献
15.
滴灌因其精量、可控而被认为是再生水最安全、可靠的灌溉方式,然而再生水中含有大量的颗粒物、营养盐分、有机物、微生物等物质使得灌水器堵塞机理变得更为复杂,堵塞风险也大幅度增加。该文在对灌水器堵塞物质-生物膜结构、组分变化特征进行分析,基于生物膜组分:干物质量(DW)、磷脂脂肪酸(PLFAs)和胞外聚合物(EPS)含量与灌水器堵塞程度之间显著的"S型曲线"关系明确了生物膜形成是诱发灌水器堵塞的根本原因。灌水器堵塞过程中表现为:再生水中微生物首先在滴灌系统毛管内部固定形成生物膜,并不断摄取、消耗水中的底物和营养物进行新陈代谢,分泌大量的胞外多聚物,并依靠胞外多聚物的黏性不断吸附微生物及固体悬浮颗粒物而引起生物膜不断形成、生长与脱落以及堵塞沉积物的不断聚集,而最终导致灌水器堵塞。从流道结构形式与几何参数、水体颗粒物特性、近壁面流动剪切力、灌溉水质以及灌水频率五个方面阐述生物膜的形成机制及影响因素。并分别从灌水器流道结构优化(增强流道自清洗能力,促进生物膜脱落)、抗菌材料开发(抑制微生物附着)、化学加氯、微生物拮抗与生长群体响应、微纳米气杀菌等多个角度出发提出了以生物膜形成为靶向目标的灌水器堵塞控制技术体系。最后从滴灌灌水器内部附生生物膜的水动力学-微生物学耦合作用机制研究、滴灌灌水器堵塞预报的综合模拟模型构建及灌水器设计参数合理阈值确定、协同考虑灌水器堵塞清除效应与土壤质量健康长期可持续发展的堵塞控制模式建立三个方面出发提出了再生水滴灌系统灌水器堵塞控制领域未来急需解决的问题。 相似文献
16.
A. Pedescoll P. R. Knowles P. Davies J. García J. Puigagut 《Water, air, and soil pollution》2012,223(5):2263-2275
Clogging is the main operational problem associated with horizontal subsurface flow constructed wetlands (HSSF CWs). The measurement of saturated hydraulic conductivity has proven to be a suitable technique to assess clogging within HSSF CWs. The vertical and horizontal distribution of hydraulic conductivity was assessed in two full-scale HSSF CWs by using two different in situ permeameter methods (falling head (FH) and constant head (CH) methods). Horizontal hydraulic conductivity profiles showed that both methods are correlated by a power function (FH?=?CH0.7821, r 2?=?0.76) within the recorded range of hydraulic conductivities (0?C70?m/day). However, the FH method provided lower values of hydraulic conductivity than the CH method (one to three times lower). Despite discrepancies between the magnitudes of reported readings, the relative distribution of clogging obtained via both methods was similar. Therefore, both methods are useful when exploring the general distribution of clogging and, specially, the assessment of clogged areas originated from preferential flow paths within full-scale HSSF CWs. Discrepancy between methods (either in magnitude and pattern) aroused from the vertical hydraulic conductivity profiles under highly clogged conditions. It is believed this can be attributed to procedural differences between the methods, such as the method of permeameter insertion (twisting versus hammering). Results from both methods suggest that clogging develops along the shortest distance between water input and output. Results also evidence that the design and maintenance of inlet distributors and outlet collectors appear to have a great influence on the pattern of clogging, and hence the asset lifetime of HSSF CWs. 相似文献
17.
This paper reports the effect of using coarse substrates in the upper layer of a gravel-based tidal flow reed bed treating pig farm wastewater. The aim of this unconventional medium arrangement is to seek a solution for the problem of clogging that frequently takes place during the treatment of strong wastewaters. Results from lab-scale experiments demonstrated that, in general, employing coarse substrates in the upper layer of the reed bed gave greater efficiency for the removal of organic matter and suspended solids, due to reduced clogging. A specific clogging tendency rate was defined to quantitatively describe the clogging behaviour. Calculation of the tendency rate revealed that the unconventional medium arrangement had a clear advantage over the conventional arrangement of employing fine gravel or sand in top layer. 相似文献
18.
滩涂围垦农田土壤饱和导水率的影响因素及转换函数研究 总被引：2，自引：0，他引：2
确定苏北沿海滩涂围垦农田耕层土壤饱和导水率的影响因素,构建适合该区的土壤转换函数,是研究该区田间土壤水盐运动和盐渍化防控的重要前提。本文在该区典型地块实测土壤饱和导水率和相关土壤基本理化性质,探讨了该区土壤饱和导水率的剖面分布特点,对影响饱和导水率的土壤基本性质进行了主成分分析,并建立了用于该区饱和导水率间接估算的土壤转换函数。结果表明:滩涂围垦农田土壤饱和导水率随剖面深度增加呈表土层高、亚表层低、底土层又升高的趋势,20~40 cm土层饱和导水率最小,介于2.75~6.73 cm·d-1,属低透水强度;土壤容重随剖面深度增加表现出与饱和导水率相反的变化特点。除了容重、孔隙度、质地等物理因素外,土壤肥力、盐分等化学性质也是影响饱和导水率的重要因素;影响滩涂围垦农田土壤饱和导水率的因素可由持水特性、盐碱状况、养分特征和土壤质地4个主成分反映,其累计贡献率达78.17%。在Vereecken转换函数中引入土壤盐分后可提高预测精度,修正函数Vereecken_1是最适合滩涂围垦农区土壤、具有最佳预测精度的转换函数。本文构建的土壤转换函数,可通过较易获得的砂粒、黏粒、容重、盐分和有机质对耕层土壤饱和导水率进行较高精度的预测,其结果可为滩涂盐渍化农区田间尺度土壤饱和导水率间接估算以及水盐运动数值模拟提供支持。 相似文献
19.
《国际水土保持研究(英文)》2022,10(3):457-469
Soil structure plays an important role in edaphic conditions and the environment. In this study, we investigated the effects of organic amendment on soil structure and hydraulic properties. A corn field in a semiarid land was separately amended with sheep manure compost at five different rates (2, 4, 6, 8 and 10 t/ha) and corn stover (6 t/ha) in combination with two decomposing agents. The soil structure of different amended soils was analyzed from the aggregate and pore domain perspectives. The internal pore structure of the soil was visualized through X-ray computed tomography and quantified using a pore-network model. Soil aggregate-size distribution and stability, saturated hydraulic conductivity, and water-retention curves were measured by sampling or in situ. The gas permeability and diffusivity of different amended soils were simulated based on the extracted pore networks. The aggregate stability of the amended soils was improved compared with the control, that is, the mean weight diameter increased and the percentage of aggregate destruction decreased. The stability of soil aggregates varied non-monotonically with the application rate of compost and decreased after treatment with corn stover and decomposing agents. The pore-network parameters including air-filled porosity, pore radius, throat length, and coordinate number increased for the amended soils compared with the control. The mean pore size increased with increasing compost incorporation rate. The saturated hydraulic conductivity of the compost-amended soils was higher than that of the control but varied quadratically with the application rate. The saturated hydraulic conductivity of soil treated with corn stover and decomposing agents was clearly higher than that without the agent and the control. The greater gas diffusivity and air permeability indicate that soil aeration improved following the incorporation of organic amendments. The air permeability versus air-filled porosity relationship followed a power law, and the gas diffusivity versus air-filled porosity relationship was characterized by a generalized density-corrected model regardless of amendment. The findings of this study can help improve the understanding of soil structure and hydrological function to organic fertilizer incorporation and further monitor the quality of soil structure through the pore space perspective. 相似文献