降雨-土壤-径流系统中氮磷的迁移

农田地表径流形成的面源污染是影响饮用水源地水质安全的主要污染源。降雨输入、土壤溶质迁移和地表径流输出三者相互作用,决定着农田面源污染负荷的产生。通过设置移动小区,收集和监测次降雨事件中的地表径流、土壤溶质迁移,研究面源污染负荷中降雨氮磷和土壤溶质输入负荷和比例。结果显示,随雨水输入径流的DTN、DTP负荷占径流DTN、DTP负荷的58%和67%;由降雨带到陆地生态系统的N、P主要通过径流输入到其它系统中,但径流NO3--N负荷主要来自土壤溶解态NO3--N向径流的溶出迁移;计算降雨-地表径流-土壤溶质的相互作用深度,简化了小流域面源污染负荷量化过程,为制定小流域面源污染防治规划提供理论指导。     

蟒河流域农林地表径流氮磷流失状况研究

济源市蟒河流域农田、林地连续2 a的地表降雨径流水质监测数据表明:该地区农田地表降雨径流氮、磷流失远远大于林地,且农田地表径流氮污染负荷较磷高;2 a间,氮和磷流失量分别为7 773 g和963 g,氮、磷年际流失量差异较大;施用化肥是造成农田径流氮、磷流失量大的主要原因.农林地表径流氮磷流失的研究,对蟒河流域造成的水...     

分布式水文模型在小流域综合治理规划中的应用

密云水库是北京市唯一的地表饮用水源,其上游山区是主要的水源涵养和供给地。位于水库上游北部山区的白马关河是一条直接进入水库的支流,虽然年径流量并不大,但是汛期随降雨径流带出的污染负荷进入密云水库,会对水库水质造成直接影响,弄清该流域降雨径流状况是进行水土流失和污染负荷估算及清洁小流域建设的基础。本研究采用分布式水文模型,对水库上游白马关河小流域内不同降雨频率下的产汇流进行了模拟计算,分析其下垫面特性对降雨径流的影响规律,为白马关河小流域的综合治理规划和非点源污染负荷控制提供参考。     

滇池流域典型城郊降雨径流CODcr及TSS污染负荷及贡献

通过野外实地监测和室内分析,系统监测了滇池流域典型城郊排放污水CODcr和TSS通量,采用城市降雨径流污染负荷的计算方法估算了城郊降雨径流CODcr和TSS污染负荷,并分析了由降雨径流引起的CODcr和TSS污染负荷占总负荷中的比例.结果表明,滇池流域城郊人均排放CODcr和TSS污染负荷分别为9.58～10.57 kg/a和2.88～3.14 kg/a;滇池流域城郊由降雨径流引起的CODcr和TSS污染负荷分别为1.166～1.458 t/(hm2·a)和0.729～1.808 t/(hm2·a).全年由降雨径流引起的CODcr和TSS污染负荷分别占总污染负荷的10.96%～15.35%和25.73%～35.89%.控制降雨径流污染是缓解滇池流域城郊面源污染的途径之一.     

植草沟对北京市道路地表径流的调控效应

[目的]分析植草沟对北京城市道路径流的水量和水质的调控效应,为北京市雨洪管理提供参考。[方法]实地建立植草沟,并根据北京市多年降雨资料和主干道路径流水质2010—2012年的监测结果设置径流水量和水质。[结果](1)降雨历时短,降雨强度低时植草沟的调控水量的功能明显。在降雨历时为3h,降雨重现期为0.33a时,50m2的植草沟可削减50m2沥青道路上产生的66%的径流量,降雨强度相对降雨历时来说对植草沟传输入渗的影响更大。(2)植草沟对水质污染物有一定的去除效果,但达不到完全净化。建设的植草沟能够削减径流中的氨氮达20%,总磷达35%,COD达22%。(3)植被覆盖度能影响植草沟的调控能力。植被覆盖度增加60%,植草沟对0.33年重现期降雨1h的雨量入渗率提高了8%。(4)若建立与北京市城六区道路等长度、宽2m的植草沟,对1a,2a重现期24h降雨形成的道路径流削减率分别为96.3%和56.0%,但对50a极端降雨道路径流量的削减率仅为13.0%。[结论]植草沟对北京市道路地表径流具有一定的调蓄洪峰流量,延缓产流时间,减少径流污染的作用,但无法单独作为有效控制城市道路地表径流水量的管理措施。     

黑河水库非点源污染时空分布研究

[目的]对黑河水库上游流域进行非点源污染模拟与分析,为水库水环境质量改善提供科学支撑。[方法]采用非点源污染—SWAT模型对流域内水文站2002—2008年的实测降雨、逐月径流以及泥沙及水质数据进行率定与验证,并对流域的非点源污染进行分析。[结果](1)非点源污染的产出主要集中在汛期(6—10月)且与降雨成正相关关系;(2)流域内降雨量分布从南向北、从山区向平原递减,径流深与降雨量成正相关,泥沙、非点源负荷的空间分布与降雨量相反;(3)不同土地利用类型单位面积的非点源污染产出不同,耕地最大,草地次之,林地最小;(4)面积耕地减少,污染负荷显著减少,耕地转换为林地的效果优于耕地转换为灌木林,退耕还林还草可有效减少流域内非点源污染负荷。[结论]黑河水库非点源污染主要发生在下游汛期6—10月,退耕还林、减少施肥可有效控制区域非点源污染。     

太原市工业区不同下垫面降雨径流污染特征

[目的]揭示太原市工业区不同下垫面降雨径流的污染特征,为探明工业水体污染的来源以及工业水污染治理提供科学依据。[方法]基于研究区2类不同下垫面的降雨径流水质监测数据,计算场次降雨径流污染物的平均浓度(EMCs)。监测项目包括化学需氧量(CODcr),NH_3—N,NO_3~-—N,TN,TP,Cu和Zn。[结果]2种下垫面条件下降雨径流的CODcr,NH_3—N,NO_3~-—N,TN和TP的浓度均超出Ⅴ类国家地表水标准,重金属污染不明显;污染物负荷(EMC)与降雨历时呈现负相关关系,符合指数回归方程。[结论]研究区降雨冲刷效应显著,随着降雨历时的增加,污染物浓度趋于降低。同时,与国内其他城市工业区相比,太原市工业区的污染程度较轻。     

嫩江流域农业面源污染管理及水质模型系统集成及应用

利用MIKE 11软件,构建了包含降雨径流模型、水动力模型、对流扩散模型和生态模型的嫩江流域农业面源污染管理及水质模型系统,并以此为基础对2020年嫩江流域农业面源污染排放量及水质状况进行预测,结果表明:2020年COD和NH+4-N比2012年削减30%和40%之后,嫩江流域各控制单元水质有明显改善,均能达到控制单元的水质目标要求。     

饮用水源区小流域氮素污染负荷估算方法比较

采用输出系数法、通用土壤流失方程估算法、径流试验场法和相关关系法4种方法对密云土门西沟小流域非点源氮污染负荷进行估算。结果表明：输出系数法中的Johnes模型和考虑降雨影响的输出系数模型计算值相对误差比较大,考虑流域损失的输出系数模型计算结果与实测结果相对误差仅为5%;输出系数方法适用于资料比较缺乏的地区,输出系数的确定是提高估算精度的关键。对流域非点源污染发生类型区和类型单元进行详细划分,并将对各类型采用径流试验场法的监测结果推算到小流域就能减小估算相对误差;采用径流试验场法推算密云土门西沟小流域非点源氮污染负荷相对误差仅为8%;相关关系法通过建立降雨和污染负荷的关系,其估算值相对误差达到4%,此方法需要长期的降雨-水质监测数据;通用土壤流失方程估算法主要估算流域土壤侵蚀量,没有考虑径流对污染物输移过程中的沉积、起动和交换等问题,估算值会偏大。     

乌鲁木齐市不同下垫面雨水径流水质特性分析

针对乌鲁木齐市面临水资源短缺和水环境污染双重压力的现状,选取乌鲁木齐城区4个不同下垫面的屋面和路面作为雨水取样点,分析了径流不同时间段雨水水质的变化趋势.结果表明:径流初期下垫面的雨水污染均较严重,污染物浓度较高.随着径流时间的持续,各污染物浓度呈下降趋势,且污染物间有一定的相关性.与此同时,依据乌鲁木齐市不同下垫面的雨水水质提出了针对乌鲁木齐市降雨特点的雨水综合利用的途径和措施,为缓解乌鲁木齐市水资源短缺问题具有一定的指导作用.     

折流式人工湿地对矿区降雨径流的净化研究

根据陕西省渭南市蒲白矿区降雨径流的水质和水量特征,采用新型折流式人工湿地对人工湿地不同运行阶段模拟降雨径流的净化效果进行了对比,分析了COD_Cr,SS,TN,TP,NH₄⁺-N以及重金属Pb,Zn,Cu在湿地系统中的沿程变化,探讨人工湿地的主要去除机制。结果表明:人工湿地对COD_Cr,TP,TN,NH₄⁺-N,SS的平均去除率分别为82.3%,65.9%,71.2%,73.5%,94.8%,对重金属Pb,Zn,Cu的平均去除率分别为91.3%,94.5%,81.2%,对重金属的去除率基本高于对营养元素的去除率;除了TN外,折流式人工湿地系统出水各污染物均达到《地表水环境质量标准》（GB3838—2002）Ⅲ类质量标准,其中TN达Ⅳ类标准,出水重金属Pb,Zn,Cu均能达地表Ⅲ类水标准。降雨径流各污染物主要在人工湿地的第1格被去除,其中,COD_Cr,TP,SS和Pb均有一半以上的去除率发生在第1格。随着人工湿地沿程进水浓度的增加,其去除率逐渐下降。研究表明,折流式人工湿地系统对矿区降雨径流的净化效果显著,并且该湿地系统具有较强抗冲击负荷能力,可用于城市地面径流污染的控制和雨水利用。     

珠海城区暴雨径流污染负荷估算及其评价

基于对广东珠海城区暴雨径流污染的监测,引用SCS模型对城区暴雨径流污染负荷进行估算并分析评价。结果表明,珠海城区暴雨产流年平均1529.2mm,其中以交通主干道和商业区径流量最大。暴雨径流污染物浓度水平较高,T—N,T—P,COD_(Cr)和BOD_5负荷总量分别为765.27,74.06,11 958.94和1104.71t,其中COD_(Cr)负荷为工业点源污染的72.32％,占珠海非点源污染总负荷的24.69％。暴雨径流在雨后短时间内会使受纳水体的水质迅速恶化。因此,珠海城区暴雨径流对水环境的威胁较大。     

大清河流域典型村镇生活污水排放规律和污染负荷研究

城乡结合部地带的村镇生活产污已经成为滇池流域水环境污染的重要来源之一,研究村镇生活污水水质特征和污染排放规律,将有助于正确认识、科学把握农村面源污染特征,有利于流域污染控制策略的制定和治理工程的开展。选择入滇池的大清河小流域中的典型村镇,采用定点动态采样的方法,研究了城郊型村镇生活污水水质特征和污染排放规律,并估算了研究区典型村镇生活污水污染负荷。研究结果表明,研究区内村镇生活污水TN、TP、CODCr浓度高,BOD5/CODCr比值低。生活污水中污染物在早上8：00和晚上18：00以后浓度较高,排放通量以及污水排放量在上午10：00和晚上20：00有两个峰值;工作日污水中CODCr浓度显著高于周末,但其他指标在工作日和周末之间没有显著性差异。污染负荷估算结果表明,研究区内的城郊村镇雨季污染物排放总量高于旱季,尤其是可溶性无机盐的排放主要集中于雨季,雨季人均污染排放量也明显高于旱季。由此指出,研究区域的城郊村镇内,生活污水单位面积污染负荷高,早上和晚上是一天内生活污水污染控制的重要时段,雨季是一年内污染控制的重要时期。     

雨水径流对受纳水体的污染特性研究

以前湖校区为研究对象,以润溪湖为受纳水体,通过对路面雨水径流及湖水在雨前、雨中、雨后的水样进行pH、浊度、SS,COD,TP和氨氮指标测试,探究各项污染物浓度在三个阶段的变化规律,对水体水质作了综合评价,进行受纳水体污染物浓度增加值与雨水径流水质相关性分析。结果表明:雨水径流的汇入,使受纳水体的pH有所降低、其余5项指标浓度均有所增加,水质类别从Ⅳ类水增加到Ⅴ类水,相关性分析结果显著,说明雨水径流的汇入是造成水体污染物增加的主要原因,显著性相关回归方程可用于推算该区域内受纳水体污染物的增加量,预测水体污染程度。并提出了相应的建议,为解决由城市雨水径流所引起的非点源污染问题提供理论参考依据。     

Surface Water Quality as Affected by Sugarcane Residue Management Techniques

This study evaluated the impacts of three sugarcane residue management techniques, namely postharvest burning of residue (BR), shredding of residue (SR), and full postharvest retention of residue (RR), on the water quality of surface runoff from February 2006 to September 2007 in Iberia, LA. Total runoff volumes recorded were 58,418, 57,923, and 46,578 L for the BR, SR, and RR treatments, respectively. Except for total Kjeldahl nitrogen (TKN), which was higher for BR than RR or SR, there were no significant differences in total loads of total suspended solids (TSS), total dissolved solids (TDS), biological oxygen demand at 5 days (BOD₅), total phosphorus (TP), nitrate-N, nitrite-N, and sulfate among the three residue management techniques, although the RR treatment generally exported the lowest total loads. Regression analyses on the pollutant load and rainfall event showed that the load exported for each water quality parameter was positively correlated with precipitation, with the BR treatment being more sensitive to rainfall amount than the RR and SR treatments in TSS, TKN, TP, BOD, nitrate, and sulfate exports. Runoff TSS and turbidity were also highly correlated (R ²?=?0.95, P?<?0.001). The results suggested that the two sugarcane residue retention practices (RR and SR) had limited benefit on improving surface runoff water quality over the BR practice in subtropical region such as Louisiana.     

青藏高原地区典型公路路域水环境特征

[目的]阐明青藏高原地区公路路域水环境特征及影响因素,为青藏高速公路建设及水环境保护措施提供理论基础及科学依据。[方法]基于2015年6—7月对共玉公路(青海省共和县至玉树县)和青藏公路(格尔木市至拉萨市)路域水环境测试结果,对青藏高原地区公路路域水环境特征及影响因素进行分析。[结果]经T检验,青藏高原地区公路路域径流污染具有显著性差异,各水质指标存在不同程度的变异性,变异系数(Cv)变化范围为11%~396%,表明不同径流水体污染物因所处位置不同而有所差异;对比了典型路域水环境特征,新建公路(共玉公路)的水环境质量好于运营期公路(青藏公路),高速公路运营后对路域水环境影响明显;对不同径流水体进行了Person检验。结果显示,悬浮物(SS)与其他水质参数之间均表现出不同程度的相关性,说明SS不仅是青藏高原地区路域径流污染的主要污染物,且是其他污染物(重金属和化学需氧量COD)的载体。[结论]路面径流是路域水环境污染的重灾区,对降雨径流进行收集处理及采用新型的路面,布置径流处理措施,将有效地降低路域水环境的影响。     

A comparative study: Prediction of constructed treatment wetland performance with k-nearest neighbors and neural networks

K-nearest neighbors (KNN), support vector machine (SVM) and self-organizing map (SOM) were applied to predict five-day @ 20?C N- Allylthiourea biochemical oxygen demand (BOD) and suspended solids (SS), and to assess novel alternative methods of analyzing water quality performance indicators for constructed treatment wetlands. Concerning the accuracy of prediction, SOM showed a better performance compared to both KNN and SVM. Moreover, SOM had the potential to visualize the relationship between complex biochemical variables. However, optimizing the SOM requires more time in comparison to KNN and SVM because of its trial and error process in searching for the optimal map. The results suggest that BOD and SS can be efficiently estimated by applying machine learning tools with input variables such as redox potential and conductivity, which can be monitored in real time. Their performances are encouraging and support the potential for future use of these models as management tools for the day-to-day process control.     

宁波地区4种典型农村生活污水处理工艺污染物去除率比较分析

选择宁波地区的A/O一体化、生物滤池、生物转盘和人工湿地等4种典型农村生活污水处理工艺为研究对象,于2013年1月—2015年12月期间开展各工艺终端处理设施的进出水水质跟踪监测,进行各处理工艺的污染物去除率和稳定性比较分析。结果表明,4种处理工艺的COD、BOD_5、SS多年平均去除率大小顺序均为A/O一体化生物滤池生物转盘人工湿地,TN多年平均去除率大小顺序为生物滤池生物转盘A/O一体化人工湿地,其中A/O一体化、生物滤池和生物转盘工艺的COD、BOD_5、TN平均去除率均显著高于人工湿地工艺;A/O一体化、生物滤池和生物转盘工艺随着终端处理设施运行年限的延长,COD、BOD_5、SS、TN去除率均保持稳定,而人工湿地工艺的COD、BOD5、TN去除率均呈现明显的下降趋势;各处理工艺在低温期(11月—次年4月)和高温期(5月—10月)的SS去除率差异不明显,但各处理工艺的COD、BOD_5、TN去除率在低温期明显低于高温期,其中A/O一体化工艺差异相对较小,生物滤池工艺差异最大。     

Cropping systems effects on snowmelt losses of solids and associated organic carbon

Increase in alfalfa (Medicago sativa L.) production for energy (gasification of stems) and protein supplement (from leaves) has been proposed for the upper Midwestern United States, an area where corn (Zea mays L.) in rotation with soybean (Glycine max L.) is the predominant crop sequence. This study was undertaken to assess the impact on runoff and water quality, especially for the loss of oxygen demanding material with snowmelt. Four field size watersheds were instrumented at Morris, Minnesota, USA on a rolling prairie landscape. Snowmelt runoff from each watershed was measured with two flumes with overlapping ranges arranged in series. An automatic water sampler collected runoff samples for chemical analysis. Oxygen demand was used as a surrogate for reduced carbon. Water samples were analyzed for total solids, biochemical oxygen demand (BOD), and chemical oxygen demand (COD). Based on the results of snowmelt events of 1997, 1998, and 1999, the alfalfa fields yielded more runoff than corn-soybean fields. The loss of total solids was more consistent from alfalfa fields. Total solids losses interacted with crop and year. Compared to alfalfa fields losses were less following soybeans and greater following corn. On average losses were similar between alfalfa and corn-soybean fields. Runoff from alfalfa fields contained about four times more BOD than corn-soybean fields. Although not statistically significant due to only two replications, there was a similar trend for COD. This study shows that although losses of total solids in snowmelt from alfalfa fields was similar to corn-soybean fields, there can be increased losses of oxygen demanding materials.     

Is mechanical soil aeration a strategy to alleviate soil compaction and decrease phosphorus and suspended sediment losses from irrigated and rain‐fed cattle‐grazed pastures?

Agriculture is a major source of phosphorus (P) and suspended sediment (SS) losses to aquatic ecosystems promoting eutrophication. Mechanical soil loosening equipments such as topsoil looseners or aerators have been reported to improve the physical quality and infiltration of soils susceptible to livestock damage resulting from treading. We hypothesized that soil aeration would significantly decrease the volume of surface runoff and consequent losses of P and SS compared with non‐aerated soil (control) in cattle‐grazed pasture on a poorly structured silt‐loam soil. Hydrologically isolated plots (2 m long × 1 m wide × 0.15 m deep) were installed in aerated and control plots to collect surface runoff following irrigation or rainfall and analysed for P and SS losses for 1 year. Soil physical properties [% macroporosity, bulk density, saturated hydraulic conductivity (K_sat) and unsaturated hydraulic conductivity (K_unsat at ?1kPa)] were measured in the aerated and control treatments and taken before each irrigation event (n = 12). Six months after mechanical aeration was employed, but before cattle grazing commenced, no significant differences in soil physical quality were found between aerated and control treatments, with the exception of a minor increase in K_unsat for the control plots. This lack of treatment difference continued after grazing and was largely attributed to the re‐settling of the poorly structured and dispersive soil. Flow‐weighted mean concentrations and annual loads of dissolved reactive P (DRP) on the mechanically aerated soil (2.24 kg DRP/ha) were approximately double those from the control treatment (1.20 kg DRP/ha). However, no significant differences were observed between treatments for surface runoff volumes and losses of total P and total SS, which may reflect the similar soil physical conditions exhibited between treatments throughout most of the trial. As observed elsewhere, time (days) since grazing or fertilizer application was found to influence P and/or SS losses. We conclude that aeration did not decrease P and SS losses. Any changes in soil physical properties such as macroporosity were short‐lived and therefore unlikely to influence surface runoff and subsequent P and SS losses for this soil type.