Recovering phosphorus (P) from excess sludge of wastewater treatment plants (WWTPs) has attracted considerable attention. An efficient P release method is undoubtedly critical for a satisfactory recovery performance. In this study, the effectiveness of three sludge pretreatment methods, i.e. anaerobic digestion (AD), EDTA-anaerobic digestion (EA) and ultrasound combined with EA (U-EA), on P release and struvite recovery from excess sludge was investigated. The results showed that different pretreatment methods resulted in the different characteristics of P release and recovery. For P release, the highest P release rate (57.14% of sludge total phosphorus, TP) was achieved by U-EA pretreatment, followed by EA and AD. Furthermore, U-EA was beneficial for sludge disintegration and reduction, by which the mixed liquor suspended solids (MLVSS) reduction rate reached 42.00% at a specific energy of 110,000 kJ/kg TS. For the P recovery (in the form of struvite), there was only a little difference in the optimal conditions and P recovery rate (89.29-94.49% of TP in the supernatant). AD pretreatment was beneficial for the purity of products and achieved the highest struvite purity (85.14%), followed by EA (80.95%) and U-EA (77.56%). In summary, the highest recovery rate of TP from excess sludge (53.50% of sludge TP) and struvite yield (26.10 mg/gSS) was obtained by U-EA.

以污水处理厂剩余污泥为研究对象,污泥经酸/碱预处理(pH=3.0/pH=10.0)后,分别以FeOOH、FeCl3及Fe2O3为外加铁源,进行厌氧发酵,探究铁源对厌氧系统中蓝铁石晶体生成的影响.结果表明:FeCl3和FeOOH可以高效地被还原为Fe2+,其铁还原效率(EFe)最高为56.24％～80.10％,且酸处理效果优于碱处理(3.00％～13.31％),而Fe2O3的EFe相对较低,最高分别为31.94％(pH=3.0)和50.1％(pH=10.0).FeOOH和Fe2O3的投加,可促进胞外聚合物(EPS)中蛋白质含量的提升,增强胞外电子传递能力,但Fe2O3因其结晶度高,阻碍了铁还原微生物对铁源的利用,导致铁还原效率低.上清液PO43-浓度、污泥Fe-P比例与EFe呈负相关,EFe越高则PO43-浓度、Fe-P比例越低.FeOOH组上清液PO43-浓度下降幅度最大,反应第9dPO43-浓度最低,仅为对照组的10.30％(pH=3.0)和17.20％(pH=10.0),其次是FeCl3组(22.83％/27.87％),Fe2O3组最终剩余较多PO43-(65.02％/56.33％);FeOOH、FeCl3 和 Fe2O3酸/碱组的 Fe-P 比例分别为 32.19％/21.20％、34.41％/23.09％和 20.92％/11.99％.铁源的添加提高了污泥的磷回收率(Rp),并且酸预处理效果优于碱处理,其中FeCl3组Rp最高,是对照组的2.91倍,其次是FeOOH组(2.63倍)和Fe2O3组(2.12倍).XRD分析表明,FeOOH和FeCl3酸/碱预处理组均生成了蓝铁石晶体.

目的：本文通过比较常规护理、手术室细节护理两种护理措施应用后对护理质量和患者情绪 状态、满意度的影响，来探讨手术室细节护理的实际应用价值。方法：68例样本均选自2019年12 月—2021年12月之间，均为于我院接受手术治疗的患者，随机将这68例样本划分为两个组别，并给 予不同的手术室护理措施，分别为常规组（34例，行常规护理）、细节组（34例，行手术室细节护 理），比较两组的应用效果。结果：细节组患者的各项护理质量评分更高，组间相较P ＜0.05；细节 组患者情绪状态更优，满意度评分更高，组间相较P ＜0.05。结论：在提高手术室护理安全性管理 工作中，采用手术室细节护理效果显著。

Phosphorus (P) recovery from waste activated sludge (WAS) of wastewater treatment plants is significant in the world suffering from P shortage. Recently, vivianite crystallization has been regarded as an essential method of recovering P from anaerobic fermentation (AF) of WAS. This study performed acid/alkali pretreatment (pH 3/pH 10) on AF of WAS to improve iron reduction and vivianite formation. The results showed that the maximum iron reduction rate (R-max) in the pH 3 and pH 10 groups was increased by 1.9 and 1.7 times compared with that in the Control-Fe group, and the iron reduction efficiency (E-Fe) was increased by 17.5% and 12.0% respectively. The Fe bound P (Fe-P) proportion in the sludge in the pH 3 and pH 10 groups increased by 50.0% and 33.7%, respectively. Furthermore, the relative abundance of the iron-reducing bacteria Clostridium_sensusensu in the pH 3 group was higher; and the Fe-P proportion in the sludge and the size of vivianite crystal after AF were larger. With these results, pH 3 pretreatment was preferred for promoting Fe2+ release and vivianite formation during AF.

Stable and reliable deformation monitoring data of concrete dam is the information basis and powerful guarantee for comprehensively analyzing the evolution law of structural morphology and evaluating the safety of long-term service. Given the characteristics of concrete dam deformation monitoring data such as small amplitude variation between neighbors, complex distribution characteristics, prominent local singular features, and the defect of traditional singular value detection methods, such as the prior hypothesis of the normal distribution, low local singular values sensitivity, and poor detection performance, the singular value detection method of concrete dam deformation based on improved local outlier factor (LOF) is established in this paper. Based on LOF that is sensitive to the local singular characteristics, differential expansion theory is applied to improve the adaptability and sensitivity to deformation monitoring data of concrete dam. A scientific and reasonable judgment standard for singular values is built with the help of the principle of small probability meanwhile. The application of engineering examples can draw that the concrete dam deformation singular value detection method based on improved LOF has high detection accuracy and stability, the recall rate of the test result is higher than 90%, the weighted evaluation indicator is higher than 80%, and the detection performance is significantly better than traditional singular value detection methods repeatedly. The application results of engineering examples show that the concrete dam deformation singular value detection method based on improved local outlier factor is highly sensitive to the singular values of concrete dam deformation, can effectively mine the local singular features of data, and has better singular value detection performance and detection efficiency.

通过对"环境监测实习"课程任务驱动教学法在教学实践过程中出现的困难与不足进行深入分析,提出了以任务为驱动力,以协作学习为策略,结合过程评价作为激励的实践教学改革思路与方案,并在环境监测实习教学中进行了探索性实施.教学实践结果证明,该教学方法可以弥补单纯任务驱动教学法的不足,提高学生学习积极性及教学过程的参与度,学生学习的效果和质量得到了明显提高.

以西北地区某已建办公住宅小区为例,分析改造需求和难点,结合海绵改造目标,采用"绿色、灰色"协同的方式,通过LID设施、管网改造、蓄水模块设计,实现了小区降雨径流削峰、调蓄、污染控制、雨水资源利用功能.通过对改造前后未落地雨水、停车场径流、小区外排口出水水质进行实地监测,评价改造后污染控制效果.结果 显示:雨水径流水质相比改造前有较大程度的改善,各污染物的年污染负荷削减率为52.2 ％～82.5％,年径流总量控制率为96.2％,均满足控制要求.

为提高剩余污泥的磷释放与回收效果,采用超声强化EDTA-厌氧处理后的剩余污泥释磷,并以鸟粪石(MAP)结晶法回收上清液中的磷,探究超声对磷释放的影响,同时确定了最佳超声工作参数,采用响应曲面法构建MAP法磷回收的二次多项式模型并验证了模型的适用性.结果 表明,超声可以强化污泥中磷的释放,最佳超声工作参数如下:声能密度为1.0 W/mL、超声时间为40 min,在最佳工作参数下可向液相释放60％的TP,TP、PO43--P浓度分别达到未超声处理的1.6倍和1.4倍;经超声后污泥上清液中TP增加量与MLSS、MLVSS减少量呈正相关关系,每溶解1 mg的MLSS向上清液中释放0.010 1 mg的TP;磷回收的最优工艺条件:nMg/nP=2、pH值=9、搅拌时间为21 min,此时磷回收率为89.29％,回收的晶体产物主要成分是磷酸铵镁,其纯度为77.56％,且相比未超声,该条件下的回收量提高了30％.

With the effective control of point source pollution, rainfall runoff pollution has become the main source of water pollution in Xi'an. Understanding the characteristics and driving factors of rainfall runoff pollution would provide theoretical foundation for urban rainfall runoff pollution control. In this study, a total of 32 rainwater samples, 604 roof runoff samples and 608 road runoff samples obtained from literature and a total of 35 rainwater samples, 127 roof runoff samples and 70 road runoff samples collected by our group were mixed to analyze the rainfall runoff pollution from 2008 to 2019. The Mann-Kendall and Logarithmic Mean Divisia Index (LMDI) method were used to determine the trend of pollution and the driving factors of water quality changes. The results showed that the major pollutant from rainwater was nitrogen, while the main pollutants from roof and road runoff were COD and SS. The rainwater quality during the study period was "clean to slightly polluted". The roof runoff quality of most years (67%) was "clean to slightly polluted". The road runoff quality was poor: 22% was "moderately polluted", and 45% was "heavily polluted". The concentration of pollutants except COD in rainwater showed a decreasing trend, while the trend of pollutants in roof and road runoff was not completely consistent with that in rainwater. NH3-N showed strong positive correlation with TN in roof runoff, which indicated common sources of these pollutants. There was a significant correlation between SS and COD in road runoff, and between SS and TP in roof runoff, suggesting SS was an important carrier of COD and TP. Technology innovation was the dominant factor affecting water quality, followed by industrial structure. Economic development and population scale contribute negatively to water quality improvement, and there was a sharp increase in the population scale effect in 2017.

为了研究陕西省渭河流域2007—2017年七市一区用水效率的影响因素与时空差异,在分析其综合、工业、农业和生活用水水平时空特征的基础上,运用灰色关联度对其影响因素进行探讨,利用泰尔系数表征其时空差异性,并将陕西省渭河流域用水水平与陕西省、全国及发达国家进行对比,结果显示:陕西省渭河流域属于国内高效用水区域,但相比发达国家仍存在较大的提升空间;2017年不同行政区工业用水效率差异最大,综合用水效率次之,农业用水效率差异最小,统计年内差距有缩减趋势;综合用水效率的主要影响因素为用水结构和产业结构,农业用水效率的主要影响因素为种植结构,而工业用水效率主要受废水治理强度和人均水资源量的影响.

Cu2O/TiO(2)heterojunction nanocomposite particles were prepared through hydrothermal method. X-ray diffractometer (XRD), static nitrogen adsorption apparatus, DelsaNano C particle analyzer, SEM, TEM, ultraviolet visible light spectrophotometer (UV-Vis) were employed to characterize and reveal the microcosmic characteristics, surface micromorphology and optical features of the Cu2O/TiO(2)heterojunction nanocomposite particles. The photocatalytic degradation regularity of rhodamine B utilizing Cu2O/TiO(2)heterojunction nanocomposite was optimized via the response surface methodology (RSM), and the quadratic regression equation of the degradation rate and coding of experimental variables were constructed. First principle calculation was applied through density function theory (DFT), the binding energies of the heterojunction of multiple Cu2O crystal surfaces and TiO(2)were computed by Vienna Ab-Initio Simulation Package. The results showed that the prepared Cu2O/TiO(2)heterojunction nanocomposite crystal nanoparticles had high purity with a Cu2O crystallization preferential orientation of (111) plane. TiO(2)doped Cu2O nanocomposite increased the forbidden band width, specific surface, dispersibility and absorbance efficiency in the visible light range. R(2)value of the constructed quadratic regression equation was 0.9233, showing the constructed regression model was available and the photocatalytic process and the established model had good fitness. The optimum conditions for the rhodamine B degradation were obtained as follows: the photocatalytic time was 3 h, the amount of catalyst was 40 mg/L and the solution pH value was 3. The experimental degradation rate of rhodamine B was predicted to be 91.8% and the relative error between the theoretical value and the experimental value was 2.8%. All the calculated binding energies of Cu2O/TiO(2)heterojunction nanocomposites were positive and Cu2O (111)/TiO(2)heterojunction nanocomposites were most likely to present high catalytic activity. The photocatalytic degradation mechanism, transfer and separation laws of photogenerated carriers of Cu2O/TiO(2)p-n heterojuncion were explored and revealed.

【目的】针对渭河流域咸阳-西安段的非点源污染状况,模拟分析不同管理措施下非点源污染负荷的削减效果,为渭河流域的非点源污染控制与治理提供科学依据。【方法】构建渭河流域咸阳-西安段的非点源污染SWAT模型,利用2008-2016年逐月径流、水质及CMADS气象数据集等资料,对SWAT模型进行率定及验证,分析研究区内非点源污染特征;针对2016年研究区内非点源污染状况,设定4种管理措施,模拟验证不同管理措施在渭河流域咸阳-西安段对非点源污染负荷的削减效果。【结果】构建了渭河流域咸阳-西安段的非点源污染SWAT模型,该模型对研究区域具有较好的适用性和可靠性;2016年研究区域非点源总氮（TN）和总磷（TP）负荷的入河量分别为7 654.0和626.5 t,主要集中在蓝田县、长安区、临潼区、鄠邑区、旬邑县以及彬县部分子流域;通过实施化肥减量、集中设置沼气池和加强水土保持等3项措施,可分别削减7.57%～29.11%、0.54%～32.85%和0.4%～23.12%的非点源TN负荷以及2.59%～15.99%、0.45%～28.65%和0%～39.79%的非点源TP负荷;将上述3种管理措施整合在一起的综合管理措施的削减效果较单一措施明显提高,其可削减9.98%～50.68%的非点源TN负荷和5.25%～52.84%的非点源TP负荷。【结论】渭河流域咸阳-西安段非点源污染的重点控制时段在汛期（6-10月）,重点控制区域是蓝田县、长安区、临潼区、鄠邑区、旬邑县以及彬县部分子流域;加强水土保持和化肥减量是有效控制该研究区域非点源污染的重要措施。

There are good prospects for phosphorus recovery from excess sludge by vivianite crystallization while a large number of extracellular polymeric substances in sludge will have impact on vivianite precipitation. In this study, as a representative of extracellular polymeric substance, the effect of sodium alginate (SA) on phosphorus recovery by vivianite precipitation under different initial SA concentrations (0-800 mg/L), pH values (6.5-9.0) and Fe/P molar ratios (1:1-2.4:1) was investigated using synthetic wastewater. The results showed that SA in low concentrations (<= 400 mg/L) had little inhibitory effect on the phosphorus recovery rate. However, when the concentration of SA was larger than 400 mg/L, the phosphorus recovery rate decreased significantly with increasing SA concentrations. The inhibition rate of 800 mg/L SA was about 3 times as large as that of 400 mg/L SA. It was worth noting that the inhibitory effect of SA on vivianite precipitation decreased with increasing initial pH and Fe/P molar ratios. Additionally, SA has no obvious influence on the composition of products, but the morphology of harvested crystals was transformed from branches to plates or rods in uneven sizes. (C) 2020 Published by Elsevier B.V. on behalf of The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Dam monitoring usually involves environmental variables (e.g., the water level and temperature) and effect variables (deformation, cracking, seepage, etc.). The associated monitoring data can reflect the trends in these variables over time and are important information for managers to understand the operational status of a dam. Therefore, research on monitoring data analysis methods is very important for monitoring dam safety. Dam monitoring data analysis methods can be divided into monitoring model, monitoring index, and abnormal value detection methods. A monitoring model takes environment variables as independent variables and effect variables as dependent variables. By studying the interactions among variables, the trends of effect variables can be learned for monitoring and prediction. A monitoring index is established to denote warning or extreme value considering the previous changes in effect variables to determine whether future changes are safe. Abnormal value detection is also an important method of finding abnormal changes in the dam state. This paper summarizes the principles, research progress, deficiencies, and development trends of these three types of monitoring data analysis methods. This review promotes research in the field of dam safety monitoring.

In order to analyze the effects of periodic factors and trend factors on the displacement of earth-rockfill dam, and grasp the cause and trend of displacement change better, the change rule and prediction method of periodic component and trend component in displacement of earth-rockfill dam were studied. HP filter was used to decompose measured displacement sequence into trend term and periodic term. MLR prediction model was established for the trend term and SARIMA prediction model was established for the periodic term, which is MLR–SARIMA model for displacement prediction of earth-rockfill dam. MLR–SARIMA model highlighted the prediction advantages of MLR model on trend data and SARIMA model on periodic data, and it only needed measured displacement data to carry out the prediction analysis. After the HP filter decompose, the trend displacement had a slow growth trend, and the annual amplitude decreased from 1.42 mm to 0.51 mm. It was shown that the trend displacement of earth-rock dam caused by aging factor decreased year by year and tended to be stable. The periodic displacement had a significant annual periodicity. This was due to the annual periodic changes of water level and temperature. The annual amplitude was about 7.00 mm. The displacement of the earth-rockill dam was mainly caused by periodic displacement.The change rule was consistent with the general earth-rockfill dam. The results showed that the HP filter can be used to extract the trend and periodic terms in displacement data of earth-rockfill dam. The prediction results of MLR–SARIMA model were accurate, the relative error was small, within 5%, theRMSE, MAPE and AMAPE evaluation index of the model were both better than single SARIMA model. It was shown that the MLR–SARIMA model highlighted its advantages in predicting trend and periodicity data, which can be applied to prediction of horizontal displacement of earth dam.

探究乙二胺四乙酸(EDTA)的添加对剩余污泥厌氧过程中磷释放及后续鸟粪石(MAP)法磷回收的影响.根据EDTA添加量对污泥上清液中总磷(TP)、蛋白质、多糖、DNA和SCOD的影响确定了最优释磷条件,采用响应曲面法(RSM)构建MAP磷回收的二次多项式模型并验证了模型的有效性.结果表明:EDTA添加量为5mmol/L,厌氧5d时预处理效果最佳.污泥SCOD破解度(DD)和TP、DNA、蛋白质及多糖均有显著相关,其中TP相关性最强,皮尔逊相关系数为0.866.MAP磷回收的最佳工艺参数是:pH=9.5,n(Mg):n(P)=1.6,搅拌时间22min,此时磷回收率可达95.68％,形成晶体的主要成分为磷酸铵镁(MgNH4PO4?6H2O),纯度为79.19％.

为了系统掌握同种污泥在不同处理方式下磷释放过程及伴生有机物的变化情况,采用厌氧、EDTA-厌氧、超声以及厌氧-超声4种预处理方式,探究处理前后TP、PO43--P、SCOD、蛋白质、多糖及DNA浓度变化特性,以及溶解性有机物的组分分布.结果 表明,在不同预处理方式下污泥释磷效果及各类有机物产生量存在差异,联合处理的释磷效果优于单一处理方式;经EDTA-厌氧、厌氧-超声处理后污泥释放的PO3--P浓度最高,分别达到6.04、10.72 mg/gVSS,其中经过EDTA-厌氧处理后产生的蛋白质、多糖、微生物副产物及腐殖酸类物质的量少,有利于后续磷回收.综合而言,EDTA-厌氧预处理的效果最优.

针对大坝变形监测数据存在的非线性强、异常值诊断和剔除工作复杂及传统监控模型抗粗差能力差等问题,结合稳健估计理论抗粗差性强和极限学习机在处理非线性问题方面的优势,建立了基于稳健估计极限学习机的大坝变形安全监控模型.试验确定网络隐含层层数,构建4次方损失函数,采用加权最小二乘法计算输出权值,实现原始监测数据的拟合和预测.以某工程大坝变形监测数据为例进行建模分析,结果表明:以反映模型预测精度的均方误差和平均绝对百分误差及反映模型鲁棒性的中位数绝对偏差作为评价指标,基于稳健估计极限学习机的大坝变形安全监控模型的各项指标明显优于对比模型.

[目的]讨论渭河干流陕西段综合整治项目启动以来河道水质的变化趋势,检验整治工程的治理成效,为后续河道的污染防治提供一定技术支持.[方法]基于2010-2016年渭河干流陕西段主要监测断面的水质数据进行水质综合评价,应用Mann-Kendall检验法阐述水质变化趋势,运用重标极差分析法(R/S分析法)查明水质的未来变化趋势.[结果] 2016年渭河干流陕西段河道水污染已由2010年的重度污染转为轻度污染,劣V类水质断面比例减少了58.8％,Ⅳ-Ⅴ类断面比例增加了55.5％,Ⅰ—Ⅲ类断面占比保持平稳;宝鸡市、咸阳市、西安市和渭南市4个出境断面枯水期化学需氧量(COD)、NH3-N浓度普遍高于丰水期,治理后西安市出境断面污染削减最为显著,但是西安市出境断面仍然是4个断面中污染最为严重的断面;4个出境断面NH3-N浓度均呈现高度显著下降趋势且未来持续性较强;咸阳、西安、渭南市出境断面COD浓度呈显著下降趋势,但是未来持续性较弱,宝鸡市出境COD浓度呈不显著上升趋势且会延续.[结论]综合治理后,河道污染程度明显减轻,水质变化明显,但部分断面污染物浓度有上升趋势,需引起特别关注.

A comprehensive risk assessment system for water transfer tunnel is established.Based on the analysis of the main factors that affect the occurrence and intensity of the risk events, the evaluation indexes of the single risk events were established by using the empirical criterion and numerical simulation, then, the risk quantitative evaluation model was constructed by means of safety grid and operation risk analysis (BORA).Results from case study showed this method can reflect the influence of each risk factor on risk events and the mitigation effect of actual engineering measures on all risk events,it has engineering application value.