湿污泥在流化床中干燥特性

在鼓泡流化床干燥器内,床料采用0～1 mm的石英砂,以热空气作为干燥介质,对城市污水污泥的流态化干燥特性进行实验研究。通过控制送风温度、流化风量、加料量、污泥粒径等参数,研究在不同工况条件下床温以及干污泥含水率的变化情况。结果表明,随着送风温度的升高,床温升高,干污泥含水率下降,最终趋向于一个稳定值8%。床温随流化风量的增加先是减小而后升高,干污泥的含水率随流化风量的增加先是降低而后增大。当加料量从11 kg/h增加到13kg/h时,干污泥的含水率基本没有变化,当加料量超过13 kg/h时,干污泥的含水率从8.1%开始呈递增趋势。随污泥粒径的增大,床温升高,干污泥含水率也随之升高。     

基于GA-BP算法的含油污泥处理 工艺参数优化

在含油污泥进行资源化处理过程中,针对处理目标受多个因素影响的实际,为了解决工艺之间的耦合问题,采用正交实验的方法来解决,并把主要参数作为优化对象,把含油污泥的脱水率作为评价目标,通过采用GA-BP算法对含油污泥耦合工艺正交实验参数进行了线性与非线性分析.在采用遗传算法优化神经网络的权值和阈值的基础上,用优化后的权值和阈值对测试样本和训练样本进行了预测.预测结果表明,预测误差都有明显减小,分别由0.34211减少到0.031549和0.15476减少到0.040682,可见耦合参数趋向于非线性优化.     

稠油废水破乳剂的研究进展

介绍了稠油废水的来源、特点和乳化成因,综述了稠油废水破乳剂的研究进展,分析了不同破乳剂的破乳机理和优缺点,并对破乳剂的发展方向进行了展望和建议。     

Evaluation of spatial-temporal variations and trends in surface water quality across a rural-suburban-urban interface

Water quality degradation is often a severe consequence of rapid economic expansion in developing countries. Methods to assess spatial-temporal patterns and trends in water quality are essential for guiding adaptive management efforts aimed at water quality remediation. Temporal and spatial patterns of surface water quality were investigated for 54 monitoring sites in the Wen-Rui Tang River watershed of eastern China to identify such patterns in water quality occurring across a rural-suburban-urban interface. Twenty physical and chemical water quality parameters were analyzed in surface waters collected once every 4–8 weeks from 2000 to 2010. Temporal and spatial variations among water quality parameters were assessed between seasons (wet/dry) and among major land use zones (urban/suburban/rural). Factor analysis was used to identify parameters that were important in assessing seasonal and spatial variations in water quality. Results revealed that parameters related to organic pollutants (dissolved oxygen (DO), chemical oxygen demand (manganese) (COD_Mn), and 5-day biochemical oxygen demand (BOD₅)), nutrients (ammonia nitrogen (NH₄ ⁺-N), total nitrogen (TN), total phosphorus (TP)), and salt concentration (electrical conductivity (EC)) were the most important parameters contributing to water quality variation. Collectively, they explained 70.9 % of the total variance. A trend study using the seasonal Kendall test revealed reductions in COD_Mn, BOD₅, NH₄ ⁺-N, petrol, V-phen, and EC concentrations over the 11-year study period. Cluster analysis was employed to evaluate variation among 14 sampling sites representative of dominant land use categories and indicated three, three, and four clusters based on organic, nutrient, and salt water quality characteristics, respectively. Factors that are typically responsible for water quality degradation (including population, topography, and land use) showed no strong correlation with water quality trends implying considerable point source inputs in the watershed. The results of this study help inform ongoing water quality remediation efforts by documenting trends in water quality across various land use zones.     

两段式混合滤料渗滤系统处理模拟废水

两段式混合滤料渗滤系统在土壤渗滤系统的基础之上,加强反硝化反应,进而强化脱氮过程。为强化脱氮,整个系统被分成好氧段和厌氧段。混合滤料的使用可有效防止系统堵塞。厌氧段添加的锯末草灰为反硝化反应提供了足够的碳源,因此运行初期厌氧段内NO3--N去除率可达100%。同时铁屑的添加除强化还原环境外还加强了TP的去除效果。采用模拟废水的研究结果表明:运行稳定后,该系统对COD、NH4+-N、TN和TP的平均去除率分别达到了87.7%、82.6%、81.0%和90.4%。     

4A沸石对复合污染水体中Pb2+、Cu2+和Cd2+的去除

采用静态吸附法以4A沸石为吸附剂研究其对复合污染水体中Pb2+、Cu2+和Cd2+的竞争吸附特性,并探讨了影响吸附的环境因素。实验表明,在室温条件下,溶液pH5～6,4A沸石15 mg对10 mL复合污染溶液(Pb2+、Cu2+和Cd2+浓度分别为100 mg/L)吸附20 min时,对溶液中3种重金属的吸附去除率均可达99.8%以上。反应过程中4A沸石对3种重金属的吸附速率大小为Pb2+>Cu2+>Cd2+。复合污染水体中4A沸石对Pb2+、Cu2+和Cd2+的吸附符合Langmuir和Fre-undlich等温吸附方程,相关系数分别为0.9981、0.9901、0.9916和0.9638、0.9194、0.9689。经计算,4A沸石对Pb2+、Cu2+和Cd2+的饱和吸附量分别为129.9 mg/g、107.5 mg/g和99.0 mg/g。4A沸石吸附重金属离子达到吸附平衡的时间较短,对溶液pH值的适应性较好。吸附后的4A沸石可以再生利用,对铅离子洗脱重复利用性较铜离子和镉离子强。     

粉煤灰微波改性及其对Cr~（6＋）的吸附特性

将粉煤灰（fly ash,FA）微波辐照制得微波改性粉煤灰（MFA）,选择用H2SO4、NaOH和Ca（OH）2对MFA进行化学改性制得微波化学改性粉煤灰（MMFA）,结果表明,用2 mol/L NaOH并按与MFA的质量体积比为1∶4制得的MMFA对Cr6＋的吸附去除效果最好,与原灰相比,去除率显著增强。研究了NaOH改性MMFA对废水中Cr6＋的吸附性能。动力学研究结果表明,MMFA对Cr6＋的吸附动力学符合二级吸附动力学速率方程,吸附受颗粒内扩散过程控制。热力学研究结果表明,在25、35和45℃下MMFA对Cr6＋的等温吸附行为均可用Langmuir方程、Freundlich方程和线性方程描述,所得热力学参数吸附自由能（ΔG）、吸附焓（ΔH）和吸附熵（ΔS）均为负值,说明MMFA对Cr6＋的吸附过程为自发进行的放热吸附过程。     

Levels and speciation of arsenic in the atmosphere in Beijing, China

Arsenic levels and speciation in the total suspended particles (TSPs) were quantitatively determined by high performance liquid chromatography on-line coupled with hydride generation atomic fluorescence spectrometry in Beijing, China from February 2009 to March 2011. The high TSP levels fluctuated between 0.07 and 0.79 mg m⁻³, with a mean level of 0.32 ± 0.17 mg m⁻³. The total arsenic concentrations ranged from 0.03 to 0.31 μg m⁻³ (mean: 0.13 ± 0.06 μg m⁻³) in Beijing‘s air. The concentrations of As(III) and As(V) ranged from 0.73 to 20 ng m⁻³ (mean: 4.7 ± 3.6 ng m⁻³) and from 14 to 2.5 × 10² ng m⁻³ (mean: 67 ± 35 ng m⁻³), respectively. As levels and speciation demonstrated relative higher levels in spring and autumn and lower values in summer and winter. As(V) accounted for 81-99% of the extractable species in the TSP samples which showed that As(V) was the major fraction of the extractable As. Organoarsenic species, monomethylarsonate (MMA) and dimethylarsinate (DMA) were not found in all samples. Higher values of enrichment factors demonstrated that arsenic in TSP mainly come from anthropogenic sources. High As and its species levels in air and respiratory exposure (0.30-0.84 μg d⁻¹) attributed to higher excess cancer risk ((4.2 ± 2.0) × 10⁻⁴) for people in Beijing.     

我国城镇污水处理厂水质监管问题及对策研究

介绍了目前我国城镇污水处理厂的发展现状以及将其作为污染源纳入监管的背景;从进水水质监管、出水水质监管和对污水处理厂内部运营管理监管的角度,结合对部分地区行政管理部门、污水处理厂的调研,分析了污水处理厂出水水质不达标的主要原因;针对我国的实际情况并借鉴国外经验,从政府部门的监管职能、政企的合作、监管技术和末端污染控制方面,给出了加强污水处理厂运行监管效果的对策。