东莞不同下垫面降雨径流污染输移规律研究

基于同沙水库集水区代表性功能区降雨径流水量、水质的监测,评价分析了东莞降雨径流污染输出过程、污染状况及初始冲刷效应等污染特征,根据径流污染负荷分配规律探讨了初期雨水截留参考标准,并应用主成分分析得出影响降雨径流污染负荷的主要因素.研究结果表明,同沙水库集水区降雨径流污染浓度值接近典型生活污水的浓度值,污染负荷较高,对同沙水库水质有严重的影响.降雨径流污染输出有较显著的时间特征且受降雨特征因素的影响,存在中等的初期冲刷效应.影响污染负荷的主因子是最大雨强、雨前干期长度、不透水率.采用FF40作为初期径流截留参考值,截留初期40%的径流比截留整场降雨径流更为经济、有效.     

太阳能电池生产废水处理工程设计

太阳能电池作为一种清洁能源,应用越来越广泛,然而其生产废水中因含有大量F-及酸碱物质,腐蚀性强,治理困难。采用石灰乳+CaCl2+PAC混凝沉淀工艺处理太阳能电池生产废水。工程设计规模为浓含氟废水7 m3/d、稀含氟废水200 m3/d、酸碱性废水200 m3/d、含IPA废水1 m3/d,经过3个多月的调试运行,出水中ρ(COD)≤500 mg/L,ρ(BOD5)≤300 mg/L,ρ(SS)≤400 mg/L,pH保持在6～9,ρ(F-)≤20 mg/L,达到GB 8978—1996《污水综合排放标准》三级标准。废水处理工艺紧凑,处理效果好、运行稳定、具有推广价值。     

北京典型土壤剖面含氧非烃化合物分布及成因

根据对北京地区6个典型采样点土壤样品的试验分析结果,探讨了含氧非烃化合物的含量、组成及其在采样点剖面上的分布特征,并对其污染源进行了讨论. 结果表明,检测到的含氧非烃化合物主要包括C₆~C₂₈正构烷酸类、C₁₂~C₂₈正构烷醇类、正构烷酸甲酯类、酞酸酯类、甾醇类和脱氢松香酸等. 含氧非烃化合物总质量分数及各类化合物的质量分数均有随深度增大而降低的趋势,其中0~40cm含氧非烃化合物总质量分数(4.539~60.689μg/g)较高且变化明显,深度大于40cm的土壤中降至<9.000 μg/g且均趋于稳定. 各采样点含氧非烃化合物的总质量分数纵向变化特征与w(TOC)的变化趋势基本一致,表明w(TOC)是控制土壤中含氧非烃化合物分布的重要因素. 不同采样点正构烷酸类化合物都以C₁₆为主峰碳,次主峰碳为C₁₈,除个别采样点表层土壤中高碳数正构烷酸存在较明显奇偶优势外,中低碳数正构烷酸偶碳优势不明显,推测其主要来源于化石燃料或原土中的有机质,部分高分子量正构烷酸来源于生物质;正构烷醇类以C₂₂为主峰碳,并具有明显的偶碳优势,主要来源于植物或者微生物源等天然源;酞酸酯中DBP(邻苯二甲酸二丁基酯)、DEHP〔邻苯二甲酸二(2-乙基己基)酯〕和DIBP(邻苯二甲酸二异丁基酯)质量分数较高,其来源与这些化合物的人为使用有关;甾醇类以β-谷甾醇占优势,并且大部分集中在表层,主要为生物源.      

塔里木河下游植被覆盖变化遥感定量分析

在RS与GIS技术支持下,采用空间模型分析法,以2 a为一研究时段,定量分析塔里木河下游输水后植被覆盖变化。结果表明:输水11 a来,Ⅳ级低覆盖植被、Ⅴ级裸地及沙地仍是研究区主要地类。与2000年相比,2010年Ⅰ级极高覆盖植被、Ⅱ级高覆盖植被、Ⅲ级中覆盖植被、Ⅳ级低覆盖植被均呈现逐级增加的趋势,分别增加了986.76、 681.84、 1 091.88、 8 641.89 hm²;Ⅴ级裸地、沙地减少了11 420.37 hm²。整个研究时段,Ⅲ级与Ⅳ级间、Ⅳ级与Ⅴ级间的转化为研究区主要转化类型。随着输水次数和年输水量的稳步增加,研究区植被覆盖类型将向覆盖度、面积稳步增长的平衡态发展,而随着输水量的减少,植被覆盖又转向类型变化频繁的非平衡态。植被覆盖度的增减变化客观反映了输水状况(输水量、输水持续时间),持续、稳定的输水是植被覆盖(覆盖度、面积)稳步增长的前提。     

大庆典型区域湿地水体污染物迁移变化特征研究

目前对于天然湿地水体污染物迁移变化规律的研究还不全面。大庆区域湿地面积较大,但石油开采所产生的含油废水以及其他生产和生活的废水进入湿地,对该区域湿地水环境产生了较大的影响。对大庆区域湿地水体自净效果及变化状况进行研究,对揭示该湿地生态系统健康状况变化有着重要意义。为此,按不同季节对湿地系统不同典型位置(进水处、出水处、中间部位),采集水样、湿地植物芦苇(Phragmiteshirsuta)与湿地土壤,考察了大庆湿地不同时空条件下的湿地水质情况以及湿地植物芦苇、土壤的变化情况。结果表明:湿地系统夏季污染最严重,污染程度从高到低依次为夏、秋、春,春季综合污染指数最低为13.11。TN的综合污染指数最高为14.05,5项水质指标综合污染指数从高到低顺序依次为TN、COD、含油量、NH4+-N、BOD5。湿地对水体污染物去除主要发生在湿地前部区域。在监测期间,湿地前部区域去除的TN的量占整个湿地区域去除TN量的71.86%,湿地前部区域去除的COD的量占整个湿地区域去除COD量的77.51%,湿地前部区域去除的NH4+-N的量占整个湿地区域去除NH4+-N量的56.46%,湿地前部区域去除的含油量占整个湿地区域去除含油量的79.91%,湿地前部区域去除的BOD5的量占整个湿地区域去除BOD5量的53.57%。湿地系统对湿地水体污染物的降解是沿湿地水流方向逐渐降低的,湿地自净效果明显。植物通过吸收直接去除部分氮、磷,而且在生长季节作用更明显。在湿地前部区域植物生长效果略好于后部,对氮、磷吸收也略高于后部,这正与湿地系统对污染物的降解是沿湿地水流方向逐渐降低相吻合。另外,湿地土壤能够吸附水中一些污染物质,湿地植物与土壤都对水中污染物的去除发挥重要作用。     

Evaluation of SWAT sub-daily runoff estimation at small agricultural watershed in Korea

A study was undertaken for the prediction of runoff flow from 0.8 ha field-sized agricultural watershed in South Korea using Soil and Water Assessment Tool (SWAT) sub-daily. The SWAT model with sub-daily configuration predicted flow from the watershed within the range of acceptable accuracy. The SWAT sub-daily simulations were carried out for a total of 18 rainfall events, 9 each for calibration and validation. Overall trend and extent of matching simulated flow for the rainfall events in 2007-2008 with measured data during the calibration process were coefficient of determination (R²) value of 0.88 and Nash and Sutcliffe Efficiency (E_NS) value of 0.88. For validation, R² and E_NS values were 0.9 and 0.84, respectively. Whereas R² and E_NS values for simulation results using daily rainfall data were 0.79 and -0.01, respectively, that were observed to be out of acceptable limits for the model simulation. The importance of higher time resolution (hourly) precipitation records for flow simulation were evaluated by comparing R² and E_NS with 15 min, 2 h, 6 h and 12 h precipitation data, which resulted in lower statistics with increases in time resolution of precipitation data. The SWAT sub-daily sensitivity analysis was performed with the consideration of hydraulic parameter and was found as in the rank order of CN2 (curve number), ESCO (soil evaporation compensation factor), GW_DELAY (ground water delay time), ALPHA_BF ( base flow alpha factor), GWQMN ( a threshold minimum depth of water in the shallow aquifer required for return flow to occur) , REVAPMN (minimum depth of water in shallow aquifer for re-evaporation to occur) , LAT_TIME (lateral flow travel time) respectively. These sensitive parameters were evaluated at 10% higher and lower values of the parameters, corresponding to 70.5% higher and 23.2% lower in simulated flow out from the SWAT model. From the results obtained in this study, hourly precipitation record for SWAT sub-daily with Green-Ampt infiltration method was proven to be efficient for runoff estimation at field sized watershed with higher accuracies that could be efficiently used to develop site-specific Best Management Practices (BMPs) considering rainfall intensity, rather than simply using daily rainfall data.     

Enhancement of sludge gravitational thickening with weak ultrasound

Gravitational thickening is the prevailing method to reduce sludge volume but the process is slow and usually requires addition of polyelectrolyte(s). This paper investigated the potential benefits of sonication on enhancing the sludge gravitational thickening with very low energy dose, so called “weak ultrasound”. Results showed that weak sonication significantly changed the sludge settlability and the main mechanism was release of the loosely bounded extracellular polymeric substances. The changes in sludge behaviors by sonication were strongly influenced by power density and sonication duration. Lower sound frequency was slightly better than higher frequency. Weak sonication (<680 kJ·kg^-1 DS) improved the sludge gravitational thickening while high ultrasonic energy deteriorated the process. Considering both the sludge thickening efficiency and energy consumption, the optimum conditions were 0.15 W·mL^-1, 7 s, and 25 kHz. Under such conditions, the energy dose was only 155 kJ·kg^-1 DS, much lower than literature reports, and the sludge settling time was shortened from 24 h to 12?h. Weak sonication could substitute expensive polyelectrolyte coagulant for sludge thickening. Combination of weak sonication and polyelectrolyte could further reduce the settling time to 6 h. The final water content of the thickened sludge was not changed after sonication or polyelectrolyte addition.     

荧光光谱法研究木栓酮与牛血清白蛋白的相互作用

为了解三萜类化合物在体内的结合转运机制,采用荧光光谱法结合紫外吸收光谱研究从中药爵床中分离的有效成分木栓酮(Friedelin,FDL)与牛血清白蛋白(Bovine serum albumin,BSA)的结合反应.通过研究木栓酮对牛血清白蛋白内源性荧光的淬灭作用,发现木栓酮可以与牛血清白蛋白相互结合,且其作用是一个静态猝灭的过程.通过计算木栓酮与牛血清白蛋白的结合常数和结合位点,发现在生理弱碱性溶液中二者具有较强的结合作用,且以1:1结合.根据热力学参数推测木栓酮与牛血清白蛋白的作用力类型为氢键和范德华力.根据F rster非辐射能量转移机理,计算出木栓酮与牛血清白蛋白结合距离为2.86 nm.研究表明木栓酮在体内可以通过血清白蛋白进行结合和转运.     

基于模糊神经网络的A2/O工艺出水氨氮在线预测模型

采用厌氧/缺氧/好氧污水处理系统(A2/O)对人工合成污水进行处理,并利用人工神经网络(ANN)模型和自适应模糊人工神经网络(ANFIS)模型对A2/O处理污水的过程进行仿真模拟.在MATLAB环境下,选取可在线监测的水力停留时间(HRT)、进水pH值(pH)、好氧池溶解氧(DO)和混合液回流比(r)作为输入参量,系统出水氨氮浓度(NH4+eff)为输出量,建立在线预测模型.结合自适应模糊C均值聚类算法,确定ANFIS模型的模糊规则数及最优运行参数,对实验数据进行仿真预测.结果表明,与ANN模型相比,ANFIS模型的仿真输出值与实际值的拟合程度更高,相对误差在6.45%之内,平均绝对百分比误差(MAPE)为2.8%,均方根误差(RMSE)为0.1209,相关系数(R)达0.9956.模型训练过程中所得到的三维曲面图,可直观的反映各因素与出水氨氮浓度之间的非线性函数关系,为A2/O系统的高效稳定运行提供指导.     

耐高浓度苯酚菌株的筛选及其降解特性研究

通过液体富集培养,平板培养分离法从焦化废水的污泥中分离出1株可耐受2 000 mg/L苯酚的菌株,经16S rDNA序列分析,鉴定为施氏假单胞菌(Pseudomonas stutzeri).该菌能以苯酚为唯一碳源和能源生长.通过摇瓶试验和高效液相色谱( HPLC)分析法可知,在pH=7.5,温度为30℃的条件下,苯酚质量浓度在50～400 mg/L时,该菌细胞生长和对苯酚的降解转换快速同步进行.当苯酚质量浓度在800～900 mg/L,菌细胞依次出现快速生长、延缓生长、次快速生长3个生长时期,在前两时期内苯酚降解率低于5％,在次快速生长期内苯酚降解率从低于5％快速增加到100％.气相色谱-质谱联用仪(Gc-MS)测定结果表明,该菌可将苯酚转化成4-羟基-2-氧代戊酸、邻苯二酚、对苯二酚、3,4-二羟基苯甲酸和对羟基苯甲酸等中间产物.