不同再生水补水比例下景观水体的水质变化

缺水地区再生水补充景观水体具有重要的意义,因此考察不同再生水补水比例条件下的水质变化尤为重要。采用修建人工景观水池的方法,模拟不同再生水补水比例条件下景观水体的水质变化规律。将某水厂的再生水和自来水按不同比例配水作为人工水池的进水和补水,水力停留时间固定为5 d。实验结果表明当该再生水所占比例为75%、50%时,水质恶化最快,100%和25%时由于营养比例失衡,水质恶化速度较慢。此外,叶绿素a的增长主要受氮磷营养盐浓度的影响,并影响着水体的浊度、色度和透明度,进而破坏景观水体的感官指标。     

改善深圳河水质的补水方案及生态影响初步分析

深圳河旱季天然径流量小而污染负荷高,为了改善河流水质,在削减入河污染物的同时有必要采取补水措施。利用水质模型,计算了不同污水处理率下,分别以污水资源化再生水、珠江口海水和大鹏湾海水为补水水源时,深圳河达到基本不黑臭所需的补水量。讨论了补水方案对河流水质、盐度、水动力条件的改变及其对生态系统的影响。研究表明,引海水对河流生态系统的冲击不容忽视。而污水资源化是较优的补水方案。     

小型景观湖水质模拟及应用研究

由于小型景观水体的体量和再生水补水措施的施行,其水质随环境和入水水质的变化和富营养化过程较大型水体快。由EFDC模型和WASP模型耦合建立小型浅水景观湖生态动力学模型,用实测水质数据进行参数率定与验证,可实现小型景观水体水质变化趋势的模拟,为水质管理提供决策支持。在此基础上,对民主湖在几种水质保障方案下1年的水质变化进行了模拟预测和对比,结果表明,作为富营养化程度表征的叶绿素a在空间和时间分布上均存在一定的规律性,夏季由于温度升高,叶绿素a浓度较高,说明藻类等浮游植物迅速增殖,是水质恶化水华暴发的高发期,而采取加大湖水水力循环和改善入口水质的控制方案,可使水质得到良好保障。     

人工湿地去除污水厂尾水中的营养元素和雌激素

利用复合垂直流人工湿地对城镇污水厂尾水进行深度处理,研究了湿地系统对水中营养元素及微量雌激素的去除效果。结果表明:复合垂直流人工湿地对污水厂尾水具有良好的处理效果;水力负荷、填料种类、植物、季节等因素影响湿地处理效果。复合垂直流湿地系统对污染物的去除作用主要发生在下行池前1/6段,种植芦苇的沸石湿地系统处理效果最佳;在水力负荷为0.12 m~3·(m~2·d)~(-1)时,运行良好的复合垂直流湿地出水水质指标达到《城市污水再生利用景观环境用水水质》标准(GB/T 18921-2002)。     

再生水补水景观湖浮游藻类群落结构特征及与环境因子的关系

在2014年6月至2015年5月,对以再生水为补水水源的天津临港生态湿地公园景观湖区的浮游藻类和水质指标进行逐月监测,应用典范对应分析(CCA)研究了浮游藻类与环境因子之间的关系,评价了湖区的水环境状况。结果表明:共鉴定出浮游藻类7门67属115种(包括变种),硅藻门种类最多,其次为绿藻门和蓝藻门,浮游藻类丰度范围为3.5×106~49×106cells·L~(-1),平均丰度为25.7×106cells·L~(-1),优势藻种主要为链状假鱼腥藻、梅尼小环藻、四尾栅藻、颤藻、项圈藻和卵形隐藻;多样性分析显示,藻类物种多样性一般,结合优势指示种评价水体为中污染富营养型水体;典范对应分析表明,水温、盐度、TN/TP等是影响临港再生水补水景观湖藻类群落结构的主要因素。     

补水景观湖水生态系统构建对水质的影响及因子分析

以广州市最大补水人工景观湖白云湖水生态系统构建示范区为对象,利用综合污染指数评价了以沉水植被构建为主的修复措施对示范区水体水质改善的影响,并应用因子分析法对各水质指标和生态因子之间的相互关系进行了研究。综合污染分析结果表明,恢复沉水植物后,示范区水体各项污染物浓度大幅降低,水质从V-劣V类提高到III-IV类,水体综合污染状态由严重污染改善为轻污染。因子分析显示,10项水质指标可划分为四类主因子来反映水质状况,其中,第一主因子主要反映水体营养盐指数,第二主因子反映水体有机污染指数,第三主因子反映温度变化对水质的影响,第四主因子反映水体的酸碱度;综合评分结果说明了生态系统构建后水质综合评分可大幅降低,且月评分结果呈现温度越高、水质越优的特点,水体特征呈现向草型水体发展的趋势。上述结果表明,水生态系统构建可有效改善示范区水质,是保障城市河道补水水源安全的有效方法。     

城市景观水体水质净化的人工湿地设计

从设计规模、水质标准、湿地平面和堤坝设计、进水方式以及防渗结构和湿地植物等方面,介绍了用于景观水体水质净化的人工湿地系统及设计方案。以西北地区某园区为例,根据天然地势设计了5级阶梯式人工湿地,确保出水水质作为景观水水源,并参与城市人工河湖系统的水循环系统的正常代谢。     

面向城市水系环境需水的再生水空间配置——以深圳市宝安区为例

以深圳市宝安区为例,探讨以再生水满足城市水系环境需水的方法.应用一维恒定与非恒定水质模型计算了4种补水水质方案下该区10条主要河流的环境需水量,从水量平衡角度提出全区再生水BOD5的平均值,并进一步分析了补水水质与河流环境需水量的关系.结合该区水系与污水处理系统空间位置,提出3种再生水的空间配置方法.结果表明:茅洲河和...     

水平潜流人工湿地处理太原市城市再生水的运行效能

以山西省太原市某污水厂的高氮低碳尾水为研究对象,开展基于3床并联的水平潜流人工湿地处理尾水的中试研究。研究结果表明,该人工湿地系统启动2个月进入稳定运行期;稳定运行期3个床体的出水水质除TN外其余指标均满足《地表水环境质量标准》（GB3838—2002）中Ⅳ类水体标准,TN指标满足《城镇污水处理厂污染物排放标准》（GB18918．2002）中一级A标准,该湿地系统出水可直接用于补充景观用水;稳定运行期3床的植物与基质的配置更适合处理同类尾水,3个床体对各污染物的去除效果均为3床〉2床〉1床;本系统中填料对污染物处理效果的影响大于植物对污染物处理效果的影响,最优填料顺序依次为沸石、砾石和钢渣,最适植物栽种顺序为芦苇、香蒲、美人蕉、黄菖蒲和芦苇。     

再生水补水河道水质的生态修复示范工程及效能分析

再生水作为生态或景观补水的重要来源,受纳水体水质下降是制约再生水回用的瓶颈。以浙江省宁波市受纳再生水的陆家河为研究对象,分析受纳再生水河道在生态集成技术修复后水体水质的变化特征,探讨生态修复工程的效能及其影响因素。结果表明,在生态修复工程运行后,显著改善受纳再生水河道的水质,氨氮、COD、总磷、CODMn、BOD5等污染负荷年平均削减率分别为69.0%、16.7%、34.3%、7.8%和34.3%。通过对再生水回用参数的研究,当再生水日进水量为4 000~6 500 m3,进水的总磷浓度控制在0.6 mg·L~(-1)以下时,能够使研究河段水体具有较好的净化效果。静态经济评价表明,研发的强化消解-生态涵养-生态观测3步生态修复集成技术,工程投资小、运行成本低、处理效果佳,具有较好的环境与经济效益。     

基于聚类分析和水质标识指数的水质评价方法

为探讨一种适用于大尺度、多断面和长时间的水质评价方法,用层次聚类分析将2006~2008年海河5个监测断面的165个水质样本分为20组,并用方差分析验证了结果的可靠性。用综合水质标识指数表示水质样本的综合特征,与单因子评价法相比,该方法充分考虑了最差水质因子的影响,避免了单因子评价法以偏概全的缺陷,且分辨率高。将评价结果分解到各断面,结果表明:密云水库、官厅水库和于桥水库的水质处于II~III类水之间,可满足作为饮用水水源水的要求,三岔口断面大部分时间为IV~V类水,张家口八号桥断面全年有6个月以上水质属于劣V类。     

万家寨引黄北干线桑干河道输水水质模拟与控制

主要对采用河道输水方案的山西万家寨引黄北干线桑干河道水质进行模拟与控制研究,依据各水体特性建立河流水质数值模型和水库数值模型,运用系统分解方法将整个研究河道分解为若干个河段,并采用情景分析方法生成3个水质模拟情景,分析模拟结果表明,在山阴取水口和怀仁取水口水质达地表水Ⅲ类标准条件下,册田水库的入水水质不达标。应用反演思想生成2个水质控制情景和3个子情景,在水库出水口水质达标的情况下,分析确定沿河各排污口的污染物排放控制量,给出了保证册田水库水质安全的控制方法。     

多水源供水管网中铁释放规律

针对水源切换而引起的水质超标现象,开展了多水源联合供水条件下管网中铁释放规律的研究。分析了北方某城市2种水源(滦河水和长江水)的水质特点,利用实验模拟反应器分别研究了水源完全置换和供水分界线处水源混合区域的铁释放规律。结果表明,多水源供水管网的铁释放速率与水源水质密切相关,特别是水中含高浓度SO2-4和氯化物时会加快铁的释放。不同水源之间的频繁切换会破坏管垢表面的钝化层,使铁释放速率迅速变化,随后会有所缓解,但新的平衡的形成需要较长时间。供水分界线处的水源混合区域,由于水质的不断变化造成管垢表面很难形成稳定的钝化层,铁释放速率持续偏高,只有当长江水所占比例高达75%以上时才能得到抑制。     

Hydrologic monitoring tools for freshwater municipal planning in the Arctic: the case of Iqaluit,Nunavut, Canada

Freshwater and the services it provides are vital to both natural ecosystems and human needs; however, extreme climates and their influence on freshwater availability can be challenging for municipal planners and engineers to manage these resources effectively. In Arctic Canada, financial and human capital limitations have left a legacy of freshwater systems that underserve current communities and may be inadequate in the near future under a warming climate, growing population, and increasing demand. We address this challenge to community water resource planning by applying several novel water supply forecasting methods to evaluate the Apex River as an alternative freshwater source for Iqaluit, Nunavut (Canada). Surveys of water isotope composition of the Apex River and tributaries indicated that rainfall is the main source of water replenishment. This information was utilized to calibrate a water resource assessment that considered climate forecasting scenarios and their influence on supply, and alternative scenarios for freshwater management to better adapt to a changing climate. We found that under current climate and demand conditions, the freshwater supply of Iqaluit would be in a perpetual state of drawdown by 2024. Analysis of current infrastructure proposals revealed significant deficiencies in the supply extensions proposed whereby the Apex replenishment pipeline would only provide a 2-year extension to current municipal supply. Our heuristic supply forecast methods allowed for several alternative supply strategies to be rapidly evaluated, which will aid the community planning process by specifically quantifying the service life of the city’s current and future primary water supply.     

Sorption and degradation of wastewater-associated non-steroidal anti-inflammatory drugs and antibiotics in soils

Presence of pharmaceuticals at trace levels in recycled water is an emerging issue impacting the beneficial reuse of treated wastewater, including practices such as irrigation and groundwater recharge in arid and semi-arid regions. To assess the environmental risks of irrigation with recycled water containing such micropollutants, in this study we evaluated sorption and degradation of five pharmaceuticals that are antibiotic and anti-inflammatory drugs in two soils collected from arid regions. Naproxen and trimethoprim showed moderate to strong sorption, while the sorption of diclofenac, ibuprofen and sulfamethoxazole was negligible in both soils. Under aerobic conditions, the studied compounds were susceptible to microbial degradation with half-lives varying from 4.8 to 69.3 d. Apart from sulfamethoxazole, the other compounds were relatively persistent under anaerobic conditions as indicated by a negligible loss over 84 d of incubation or half-lives >50 d. The degradation of the selected pharmaceuticals was influenced by microbial activities, oxygen status in the soil, soil type and compound characteristics. The poor sorption and relative persistence of diclofenac and ibuprofen under anaerobic conditions suggest that the two chemicals may pose a high leaching risk when using recycled for irrigation or groundwater replenishment.     

基于地理信息系统的引江济巢数值模拟系统的研究

以引江济巢工程为对象,在充分搜集巢湖流域水环境信息的基础上,利用Visual Basic6.0结合MapObjects2.0开发基于地理信息系统(GIS)的引江济巢数值模拟系统,实现对引江济巢工程基础地理信息、水文信息、水质信息等的统计、分析与管理。并通过嵌入式集成方法实现数学模型与GIS的紧密集成,实现了在污染因素由用户自行设定下进行"所见即所得"的动态仿真能力,为引江济巢调水方案的论证和调水过程中的环境管理提供技术支撑。     

Water quantity and quality dynamics of the THC — Tuyamuyun Hydroengineering Complex — And implications for reservoir operation

Background In the Aral Sea basin, safe water resources are scarce and steadily becoming scarcer. Particularly high quality water is going to become a rare good. The object of the study was the Tuyamuyun Hydroengineering Complex (THC), a complex of artificial water reservoirs located in the lower Amu Darya River, which provides water for irrigation, industry, and drinking for the lower Amu Darya region. The focus was on operation of one of its four reservoirs, the Kaparas, which is mainly used for drinking water supply. The objective includes the investigation of impacts of conventional operation schemes on the reservoir water quality for improving drinking water quality (salinity). Basic operation rules for Kaparas, which can be considered as representative for conventional dam operation under dry year conditions, had to be identified and improved operation schemes derived. Methods Existing data archives were analysed, and further data were acquired from field surveys, data processing and modelling studies. Historical data were identified, which are appropriate to determine representative schemes for the conventional operation. For the simulation of time-dependent and depth-dependent changes of reservoir salinisation, the reservoir water quality model Lac was used and linked with the THC model. Results and Discussion Modelling results for the simulation of temperature dynamics and density stratification showed a sufficient congruence with the measured temperature profiles. The conformity of measured and calculated salt concentration is basically ensured. The reservoir, which fill with higher saline water at the end of the summer, aggravates the entrainment of high saline water in the entire water column. Conclusions The current conventional operation regime mainly leads to filling the Kaparas reservoir with high saline water during the winter months. Even in the event of starting with comparable low salinity levels, the simulation demonstrates the rapid deterioration of the reservoir water quality. Under dry year conditions, the WHO standards for drinking water will be exceeded by 30% after two years, so that the impact of dry years in the context of water stress becomes visible. Recommendations and Outlook Processed data and results are now available to identify enhanced reservoir operation strategies for salinity reduction by changing the period of reservoir filling and release, as well as to initiate a detailed analysis of how water deficits in dry years may be reduced by improved operation regimes. Using adapted and enhanced operation rules for THC reservoirs, the local population within the lower Aral Sea basin might be supplied with more potable water of higher quality in future.     

Development of the hybrid cells in series model to simulate ammonia nutrient pollutant transport along the Umgeni River

Discharge of organic waste results in high nutrient pollution of the water bodies which is a major menace to the environment. A high quantity of nutrients such as ammonia causes a reduction in the dissolved oxygen level and induces algal growth in the water bodies. Water quality models have been the tools to evaluate the rate at which streams can disperse the pollutants they receive. Many water quality models are flawed either because of their inadequacy to completely simulate the advection component of the pollutant transport, or because of the limited application of the models, due to inaccurate estimation of model parameters. The hybrid cell in series (HCIS) developed by Ghosh et al. (2004) has been able to overcome such difficulties associated with the mixing cell-based models. Thus, the current study focuses on developing an analytical solution for the pollutant transport of the ammonia concentration through the plug flow, the first and second well-mixed cells of the HCIS model. The HCIS model coupled with the first order kinetic equation for ammonia nutrient was developed to simulate the ammonia pollutant concentration in the water column. The ammonia concentration at various points along the river system was assessed by considering the effects of the transformation of ammonia to nitrite, the uptake of ammonia by the algae, the respiration rate of the algae and the input of benthic source to the ammonia concentration in the water column. The proposed model was tested using synthetic data, and the HCIS-NH₃ model simulations for spatial and temporal variation of ammonia pollutant transport were analysed. The simulated results of the HCIS-NH₃ model agreed with the Fickian-based advection-dispersion equation (ADE) for simulating ammonia concentration solved using an explicit finite difference scheme. The HCIS-NH₃ model also showed a good agreement with the observed data from the Umgeni River, except during rainy periods.     

湘江株洲段丰水期镉污染负荷总量测算及分配

以2010年8月湘江干流株洲段代表性断面水质与底泥监测资料以及其他资料为基础,采用WASP7模型模拟该江段丰水期镉浓度,并进行镉污染负荷测算与分配。研究结果表明,WASP7模型较好地重现了镉浓度的变化规律,8月份该河段上游镉入流量2 446.33 kg,下游出流量3 076.44 kg,区间增量630.12 kg,其中点源负荷量241.67 kg,占38.4%,面源负荷量304.49 kg,占48.3%,内源负荷量为83.96 kg,占13.3%。