城市水质实时监测系统设计与应用

针对目前大众普遍关心的城市饮用水质质量问题,设计完成了基于无线传感网的在线水质监测系统.系统采用CC2530和MSP430F1611二种MCU来实现水质检测感知节点功能,利用无线传感网的技术优势,结合多传感器前端检测,实现对城市水质多指标的实时监测.系统经过近1年实际使用,完全满足城市水质监测的需要,受到了用户的好评.     

城市污水管网中水质变化特性

以管网中城市污水为研究对象,通过模拟管道的循环流动研究了水质变化特性。结果表明,在水力流动6 h的条件下,因管道沉积和管内微生物作用,城市污水中的TCOD(总有机物)去除率为10.79%,其中,沉积和生物降解作用对TCOD去除的贡献率分别为68.85%和31.15%。而管道中的氮类污染物的去除率为11.15%,管道沉积与生物降解作用各占约50%,其中生物降解引起的氮类污染物的变化主要是水中有机氮转化为NH3-N(NH3-N由35.51 mg/L升至38.38 mg/L),以及反硝化作用造成的NO3-N转变(NO3-N由2.36 mg/L降至0.84 mg/L)。总磷的变化相对较小,与管道内相对稳定的缺氧环境有关。     

基于地统计学—克里格插值法的村镇地表水体水质监测

采用普通克里格、以溶解氧为辅助变量的协同克里格、以UV254为辅助变量的协同克里格、回归克里格和与BP神经网络相结合的克里格等5种插值方法,对湖南省乔口镇典型地表水体新河中的COD进行空间分布预测。结果表明,新河中COD具有强烈的空间自相关性,半方差函数拟合程度较高,为克里格插值提供了良好的理论基础。5种插值方法预测结果符合污染源分布的现场勘查情况,较好地反映了水体中COD的空间分布规律。插值精度表现为以UV254为辅助变量的协同克里格法最佳,并且随着插值点数量的下降,各种插值方法的精度整体呈下降趋势。     

Assessment of 2010 air quality in two Alpine valleys from modelling: Weather type and emission scenarios

Alpine valleys are sensitive to anthropogenic emissions. Local atmospheric dynamics are a key factor that may lead to an accumulation of pollutants in the bottom of the Chamonix and Maurienne valleys. Assessment of 2010 pollutant concentrations variability needs to take these specificities into account. A meteorological data classification is combined with different emission scenarios in order to run an air quality model. Using simulations of representative scenarios rather than complete years allows for a fine spatial and temporal representation of local atmospheric dynamics and gives access to detailed chemical breakdowns. Results demonstrate the variability of primary and secondary species due to emissions and the predominance of local effects on pollutant concentrations.     

Impacts of afforestation on water quality trends in two catchments in mid-Wales

The impact of afforestation on stream-water chemistry for two catchments in central Wales is investigated. Trends in water chemistry are evaluated with forest age progressing at 8-15 years and 20-27 years. To assess the possible exacerbating effect of afforestation on surface-water acidification two moorland catchments are used as controls. Absolute differences in inter-catchment streamwater chemistry are evident. Differences in acidity between the moorland and the young forest site reflect site preparation and modifications to water pathways. Differences in the observed present day chemistry between the young and old forest result from past interactions between deposition changes during forest development. An estimate of the future impact of forest growth was attained from model predictions. The model was calibrated to present day stream-water chemistry and incorporates, cation uptake, evapotranspiration/ concentration effect and increased scavenging of occult and dry deposition. Predictions suggest the pH will decline to 5.3 when the young forest progresses to 20 years of age, which is still much higher than the pH recorded at the older forest site at the age of 20 years.     

不同基质与布水方案下人工湿地水分运移的模拟

以垂直潜流人工湿地为背景,采用饱和-非饱和土壤水分运动Richards方程,基于HYDRUS-3D模型对2种具体土质、不同布水方案下土壤水分运移情况进行了数值模拟,并依据相关数值结果进行水力停留时间的计算.模拟结果显示,土质的渗透性对表层土壤含水量影响很大;相同布水总量下,布水次数增加将导致砂土表层土壤含水量峰值降低、土壤水力停留时间减小.研究可为潜流人工湿地基质、布水模式的选择提供相关科学依据.     

Performance of ANFIS versus MLP-NN dissolved oxygen prediction models in water quality monitoring

We discuss the accuracy and performance of the adaptive neuro-fuzzy inference system (ANFIS) in training and prediction of dissolved oxygen (DO) concentrations. The model was used to analyze historical data generated through continuous monitoring of water quality parameters at several stations on the Johor River to predict DO concentrations. Four water quality parameters were selected for ANFIS modeling, including temperature, pH, nitrate (NO₃) concentration, and ammoniacal nitrogen concentration (NH₃-NL). Sensitivity analysis was performed to evaluate the effects of the input parameters. The inputs with the greatest effect were those related to oxygen content (NO₃) or oxygen demand (NH₃-NL). Temperature was the parameter with the least effect, whereas pH provided the lowest contribution to the proposed model. To evaluate the performance of the model, three statistical indices were used: the coefficient of determination (R ²), the mean absolute prediction error, and the correlation coefficient. The performance of the ANFIS model was compared with an artificial neural network model. The ANFIS model was capable of providing greater accuracy, particularly in the case of extreme events.     

基于氨氮实测结果的水质自动监测系统数据质量分析

为提高水质自动监测数据质量,在地表水水质自动监测系统实际监测运行环境中,基于统计分析方法,探讨水质自动监测日常运行维护质控手段对运行维护质量监督考核结果的影响,探索提高水质自动监测质控考核结果合格率的运行维护质控技术要求。结果表明：零点漂移检查、量程/跨度漂移检查对水质自动监测质控考核结果虽无显著影响,但却是保障水质自动监测数据质量的基础;水质自动监测仪标准物质核查结果相对误差的合格判定标准由±10%加严至±6%时,水质自动监测仪标准物质核查、实际水体样品比对测试、实际水体样品加标回收率测试及盲样考核结果的合格率均显著提升;标准物质核查合格率由74.6%~77.9%提升为98.4%~100%,实际水体样品比对测试的合格率由62.5%提升为75.9%,实际水体样品加标回收率测试的合格率由75.0%提升为87.5%~100%,盲样考核合格率由75.0%提升为100%;标准物质核查及实际水体样品比对测试相对误差均不服从正态分布,且数据分布为正偏态分布;实验所用水质自动监测仪器可能存在负偏离的系统误差,手工比对实验环节对实际水体样品比对测试结果也可能存在一定干扰。综合上述结果,在进行水质自动监测仪器设计和选型时,应消除可能的系统偏差;在开展实际水体样品比对测试过程中,应加强对比对实验相关环节的质量监督和检查;在水质自动监测系统运行维护时,应采用更严格的标准物质核查结果相对误差合格判定标准,以提高和保障自动监测数据质量。相关研究成果可为水质自动监测系统运行维护采取的质量控制措施和评价标准的制定提供技术支持。     

水质对紫外消毒在两种典型再生水中应用的影响

以大肠杆菌为对象,研究了再生水水质变化对紫外消毒效果和光复活的影响。结果表明,紫外对大肠杆菌有很强的灭活作用,在紫外剂量为4mJ／cm^2时,大肠杆菌的灭活率达到了4．41个对数级。腐殖酸、铁和2种再生水水体中其他溶解性物质会影响光吸收和紫外透射率,但对紫外消毒动力学无影响。在颗粒物浓度为0～200mg／L的范围内,外源高岭土和活性污泥等颗粒物的投加对紫外消毒效果影响较小,而再生水水样W1中原有的2．61／1：g／L的颗粒物则会极大地影响消毒效果,使UV对细菌的灭活出现明显的拖尾现象。腐殖酸会增强紫外损伤大肠杆菌的光复活能力,但2种再生水中细菌的光复活能力相对磷酸盐缓冲溶液（PBS）中减弱,减弱程度在不同水样中有所不同。     

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。     

A methodology for the quantification of the net African dust load in air quality monitoring networks

This paper proposes and validates a methodology for the quantification of the daily African PM load during dust outbreaks in southern Europe. The daily net dust load in PM10 attributable to an African episode in a given region can be obtained by subtracting the daily regional background (RB) level from the PM10 concentration value at an RB station. As demonstrated in this paper, the daily RB level can be obtained by applying a monthly moving 30th percentile to the PM10 time series at an RB station after a prior extraction of the data of the days with African dust transport. The daily PM10 RB levels obtained can be subtracted from the daily PM10 levels recorded at the same RB site only on days when the occurrence of African dust outbreaks was demonstrated, the difference being the daily net African dust load. It is thus possible to quantify the African dust contribution during an African PM event in southern Europe without the need for PM speciation.The validation of this methodology was performed by comparing the estimated net dust load during African dust outbreaks at three RB stations and the crustal load determined by chemical speciation of PM10 filters. The correlation (r²>0.6) and the equivalence (correlation lines’ slopes ∼1) were significant in the three cases.     

基于TM数据和ANN的河流水质参数监测研究

以珠江水系广州河段为研究对象,联合使用遥感（RS）和人工神经网络（ANN）技术对珠江水质进行分析监测。这种技术主要是利用GIS对RS图像进行地理定位,然后利用RS专用软件提取定位点的RS数据,最后通过建立前馈误差反传人工神经网络（BP网络）,确定TM数据前5个波段在定位点的反射率与水质3个主要参数的映射关系,即建立RS数据与水质的映射模型。经过检验,该技术监测误差小于16%,基本能满足当前实际需要。     

Sampling strategies for water quality monitoring in lakes: the effect of sampling method

Five different water sampling techniques have been compared in a series of lakes. In deep lakes, no significant differences were observed between mean summer nutrient concentrations measured in (i) a tube sample integrating over the photic zone taken from the deepest point; (ii) a surface dip sample taken at the deepest point; (iii) a surface dip sample taken by wading into the water's edge; (iv) a dip sample taken slightly further off shore by suspending a bottle below a buoy thrown out about 30 m from the shore; and (v) a sample taken along a short transect out from the shore using a model boat to transport the sample bottle. In shallower lakes the integrating tube sampler gave significantly higher estimates of mean concentrations than other methods due to the increase in volume of the unmixed hypolimnion which reduced the depth of the well mixed epilimnion to less than the tube length. For national survey purposes samples taken from the edge of the lake are the most cost effective.     

UV spectra analysis for water quality monitoring in a fuel park wastewater treatment plant

In the context of the high application potentials for on-line measurements in wastewater quality monitoring, UV spectroscopy has received recent attention. In the present work UV spectrophotometric analyses were coupled to principal component analysis (PCA) and cluster analysis (CA) to characterize samples taken from a fuel park wastewater treatment plant and to attempt preliminary contaminant identification in the treated wastewater. The score plot resulting from PCA identified two different groups of spectra, one including the influents to the biological reactor and the other the treated wastewater samples. Among the latter, weekday and weekend samples could be further distinguished. The same groups of samples were identified in a dendrogram from CA. The score plot and the dendrogram also allowed the tentative identification of employed process chemicals (lubricant and detergents) as residual contaminants in the treated effluent.     

Calibration and validation of a dynamic water model in agricultural scenarios

A dynamic aquatic model (DynA model) was previously developed to predict the fate of a chemical in aquatic scenarios characterized by daily or periodic changes in several input parameters. DynA model is here calibrated with data obtained from the literature in specific unsteady state scenarios, such as those of rice fields. The results obtained for two herbicides (cinosulfuron and pretilachlor) in rice paddy scenarios revealed the capability of the model to accurately predict water and sediment concentrations, as shown by some statistical indicators. Modelling efficiency (EF) values of 0.86-0.99 for the water compartment and of 0.77-0.84 for sediment show the good agreement between predicted and measured concentrations. An "external validation" was performed using measured data for a different herbicide (molinate) applied in a Portuguese paddy rice scenario. A sensitivity analysis for this volatile chemical revealed the influence of some climatic parameters (e.g. temperature) to the model outcomes, such as water and sediment concentrations. This confirmed the capability of DynA model as an efficient tool for the pesticide risk assessment in dynamic scenarios.     

2种耐寒生态浮床植物的水质改善性能研究

引种了2种陆地湿生的耐寒植物——黄菖蒲和西伯利亚鸢尾作为生态浮床植物,以水生美人蕉为对比,进行了水质改善实验研究。在6个月实验期内,黄菖蒲、西伯利亚鸢尾和美人蕉（5个月）对SRP的平均去除速率分别为79.27、20.92和34.29 mg/（m²?d）,对TP的平均去除速率分别为86.92、24.91和36.6 mg/（m²?d）,对NH⁺₄-N的平均去除速率分别为517.54、170.57和274.07 mg/（m²?d）,对TN的平均去除速率分别为763.79、301.81和384.04 mg/（m²?d）。黄菖蒲年去除磷的量21 207.64 mg/（m²?a）,是西伯利亚鸢尾的2.6倍,是美人蕉的3.8倍;年去除氮的量186 365.78 mg/（m²?a）,是西伯利亚鸢尾的1.9倍,美人蕉的3.2倍。黄菖蒲和西伯利亚鸢尾耐寒能越冬,生长期长,管理工作量小。     

Ecotoxicity of imidacloprid to soil invertebrates in two tropical soils with contrasting texture

Environmental Science and Pollution Research - Imidacloprid is one of the most commercialized insecticides in agriculture in the world, with a broad spectrum of action. However, little is known...     

Comparison of topological,empirical and optimization-based approaches for locating quality detection points in water distribution networks

Environmental Science and Pollution Research - The positioning of quality detection points as well as the frequency of sampling is a crucial aspect for the implementation of Water Safety Plans...     

Comparative studies of water quality in two brackish ponds for shrimp cultivation in a salt marsh

Physical, chemical and microbiological characteristics of two 'keiwais' (brackish ponds built along the coastal area for shrimp cultivation) in the Mai Po Marshes, Hong Kong, were measured and compared. One keiwai, located closer to the domestic and agricultural areas, had lower shrimp production than the other. Physical, microbiological and most of the chemical parameters of two keiwais showed no significant difference, while the keiwai closer to the domestic and agricultural areas had higher biochemical oxygen demand (BOD5), and higher levels of phosphate (PO4(3-)-P) and cadmium (Cd2+). Results of the present study indicate that these keiwais were polluted by sewage discharged from nearby domestic, agricultural and industrial areas. The possibility that water received by the less polluted keiwai was purified by surrounding mangroves and sediments in the Mai Po Marshes is discussed.