Control of membrane fouling during hyperhaline municipal wastewater treatment using a pilot-scale anoxic/aerobic-membrane bioreactor system

Membrane fouling limits the effects of long-term stable operation of membrane bioreactor (MBR). Control of membrane fouling can extend the membrane life and reduce water treatment cost effectively. A pilot scale anoxic/aerobic-membrane bioreactor (A/O-MBR, 40 L/hr) was used to treat the hyperhaline municipal sewage from a processing zone of Tianjin, China. Impact factors including mixed liquid sludge suspension (MLSS), sludge viscosity (μup), microorganisms, extracellular polymeric substances (EPS), aeration intensity and suction/suspended time on membrane fouling and pollution control were studied. The relationships among various factors associated with membrane fouling were analyzed. Results showed that there was a positive correlation among MLSS, sludge viscosity and trans-membrane pressure (TMP). Considering water treatment efficiency and stable operation of the membrane module, MLSS of 5 g/L was suggested for the process. There was a same trend among EPS, sludge viscosity and TMP. Numbers and species of microorganisms affected membrane fouling. Either too high or too low aeration intensity was not conducive to membrane fouling control. Aeration intensity of 1.0 m³/hr (gas/water ratio of 25:1) is suggested for the process. A long suction time caused a rapid increase in membrane resistance. However, long suspended time cannot prevent the increase of membrane resistance effectively even though a suspended time was necessary for scale off particles from the membrane surface. The suction/suspended time of 12 min/3 min was selected for the process. The interaction of various environmental factors and operation conditions must be considered synthetically.     

新型错位板对静电除尘器流场影响的数值模拟

为降低现有除尘器的改造成本,提高微细粉尘的收集效率,在现有除尘器的基础上,对阳极板排布方式进行调整,设计错位排布方式,最大化地利用原有除尘器的资源,以最小的改造成本,达到较满意的除尘效果.利用目前应用广泛的FLUENT仿真软件进行数值模拟,观察分析了其电势分布和气流分布.数值模拟结果表明:当主流风速小于0.5 m·s-...     

方便面6种真菌毒素的监测分析

为监测并了解方便面中6种真菌毒素的污染状况,样品经乙腈甲酸水溶液提取,采用高液相色谱-串联质谱多反应监测负离子模式进行检测,内标法定量,依据食品安全国家标准-食品中真菌毒素限量进行判断.6种真菌毒素在0.2—400μg·L~(-1)范围内有较好的线性关系(r0.99),回收率为87.6%—101.3%,相对标准偏差为1.1%—3.7%.玉米赤霉烯酮、赭曲霉毒素及脱氧雪腐镰刀菌烯醇检出率分别为27.3%、51.5%及90.9%,超标率分别为3.0%、12.1%及3.0%,其余3种毒素均未检出.     

An improved algorithm for retrieving chlorophyll-a from the Yellow River Estuary using MODIS imagery

In this study, an improved Moderate-Resolution Imaging Spectroradiometer (MODIS) ocean chlorophyll-a (chla) 3 model (IOC3M) algorithm was developed as a substitute for the MODIS global chla concentration estimation algorithm, OC3M, to estimate chla concentrations in waters with high suspended sediment concentrations, such as the Yellow River Estuary, China. The IOC3M algorithm uses $ {{{\left[ {R_{\text{rs}}^{{ - 1}}\left( {{\lambda_{{1}}}} \right) - {k_1}R_{\text{rs}}^{{ - 1}}\left( {{\lambda_{{2}}}} \right)} \right]}} \left/ {{\left[ {R_{\text{rs}}^{{ - 1}}\left( {{\lambda_{{3}}}} \right) - {k_{{2}}}R_{\text{rs}}^{{ - 1}}\left( {{\lambda_{{4}}}} \right)} \right]}} \right.} $ to substitute for switching the two-band ratio of max [R _rs (443 nm), R _rs (488 nm)]/R _rs (551 nm) of the OC3M algorithm. In the IOC3M algorithm, the absorption coefficient of chla can be isolated as long as reasonable bands are selected. The performance of IOC3M and OC3M was calibrated and validated using a bio-optical data set composed of spectral upwelling radiance measurements and chla concentrations collected during three independent cruises in the Yellow River Estuary in September of 2009. It was found that the optimal bands of the IOC3M algorithm were λ₁?=?443 nm, λ₂?=?748 nm, λ₃?=?551 nm, and λ₄?=?870 nm. By comparison, the IOC3M algorithm produces superior performance to the OC3M algorithm. Using the IOC3M algorithm in estimating chla concentrations from the Yellow River Estuary decreases 1.03 mg/m³ uncertainty from the OC3M algorithm. Additionally, the chla concentration estimated from MODIS data reveals that more than 90 % of the water in the Yellow River Estuary has a chla concentration lower than 5.0 mg/m³. The averaged chla concentration is close to the in situ measurements. Although the case study presented herein is unique, the modeling procedures employed by the IOC3M algorithm can be useful in remote sensing to estimate the chla concentrations of similar aquatic environments.     

长江(南京段)环境雌激素的污染特征

利用固相萃取技术和重组基因酵母检测了长江(南京段)四个典型断面环境雌激素污染状况.结果表明,除秦淮新河断面外,江心洲断面、三汊河断面和大桥断面均有环境雌激素的检出,雌二醇当量分别为0.38、0.24和0.45 ng·L~(-1).与国内外地表水环境雌激素检测结果相比,长江(南京段)典型断面雌激素活性水平为较低至中等.对江心洲断面和大桥断面,甲醇洗脱组分的雌激素活性最大,其次为丙酮洗脱组分,二氯甲烷洗脱组分的雌激素活性最小;对三汊河断面,丙酮洗脱组分的雌激素活性最大,其次为二氯甲烷洗脱组分,甲醇洗脱组分的雌激素活性最小.这可能是污水来源不同所致,生活污水导致大量极性雌激素污染物的输入,而工业污水则主要引入了中等至弱极性雌激素污染物.三个雌激素活性阳性检出断面主要活性洗脱组分的雌激素活性均大于混合样的雌激素活性,这可能是由于样品混合后各种结构上不同的污染物之间的交互作用掩盖了实际的雌激素活性.     

腐蚀环境下飞机结构日历寿命研究现状与关键技术问题

介绍了军用飞机日历寿命研究的技术背景和国内外同类研究概况以及存在的问题。重点对腐蚀环境下飞机结构加速腐蚀试验技术、防腐涂层腐蚀损伤评定技术、腐蚀损伤和疲劳寿命的分布特性及其变化规律、腐蚀当量关系和日历寿命理论分析方法等几个关键问题及其技术途径进行了阐述和探讨。     

油田污水去除成垢离子处理技术研究

在高效气浮除油、多种新型过滤分离技术的基础上,利用特种阴离子交换树脂去除油田污水中成垢离子的方法,解决了油田在注水开发中管线、设备及地层存在的结垢问题,处理后水质达到油田回注要求。同时在污水处理过程中,对"三废"的有效处置和循环使用,也达到了绿色环保的要求,为油田企业做进一步的实验和推广,起到一定作用。     

庆阳市环境-经济耦合系统动态演变趋势分析:基于能值理论与计量经济分析模型

分析了1978～2007年庆阳市环境-经济系统的能值流量与能值效率的演变轨迹.并以环境负荷率(ELR)、能值废弃率(EWR)作为环境压力指标,运用协整检验、Granger因果检验和向量误差修正模型(VECM),通过分析人均GDP与环境压力指标变量之间在时序维度上的因果关系和相互影响程度,进一步阐述经济与环境系统的耦合关系及其动态特征.结果表明,庆阳市经济发展对不可更新资源的依赖度大,环境-经济系统的产出效率总体下降,但环境负荷不断上升.计量分析表明,经济增长与环境压力之间存在单向因果关系,且已形成"恶性循环圈",环境-经济耦合系统表现出不可持续的发展态势.     

面向安全管理的安全情报服务能力影响因素研究*

为研究安全情报服务能力影响因素,根据安全情报与情报服务理论,提出安全情报服务定义及内涵,以4个基本原则为指导,面向安全管理全过程,构建并解析面向安全管理的安全情报服务能力影响因素模型,并提出安全情报服务能力建设的工作建议。研究结果表明:面向安全管理的安全情报服务能力影响因素包括安全情报服务顶层设计、安全情报服务机制和安全情报服务保障3个一级影响因素,且一级影响因素可进一步细分为10个二级影响因素。研究结果可为提升面向安全管理的安全情报服务能力提供重要支撑。     

Ultraviolet photolysis of four typical cardiovascular drugs: mechanisms,influencing factors,degradation pathways,and toxicity trends

Environmental Science and Pollution Research - The cardiovascular drugs (CDDs), such as metoprolol (MET), atenolol (ATE), bezafibrate (BZB), and atorvastatin (ATO), have been frequently detected in...