厌氧膨胀床处理低浓度污水的污泥颗粒和生物活性变化

污泥的聚集形态和活性,是影响厌氧反应器处理效率的关键因素。通过对厌氧膨胀床反应器（anaerobicex—pandedblanketreactor,AEBR）处理低浓度城镇污水在启动和稳定运行期的污泥活性研究,AEBR在启动运行期内,接种颗粒污泥为适应低浓度基质条件,污泥粒径经历从大变小,再重新颗粒化粒径变大的过程。在运行期第103天,粒径小于1000μm污泥的体积比达到44．7％,平均粒径为952μm,到运行期第173天,粒径小于1000μm污泥的体积比降为28％,平均粒径达1179μm,污泥重新颗粒化完成。颗粒污泥适应新的环境后,单位重量污泥的最大比产甲烷活性（specificmetha．nogensisactivity,SMA）值和胞外聚合物含量增加,分别达到112mLCH4／（gVSS·d）和215mg／gVSS。在处理实际城镇污水的AEBR反应器内,辅酶F420含量可以有效指示污泥样品的产甲烷活性,AEBR反应器不同高度位置的污泥活性不一样,反应器底部污泥活性低于中上部区域污泥的活性。     

曝气强度对同时硝化反硝化（SND）脱氮过程中N2O排放的影响

为了控制污水脱氮中N2O排放,在不同曝气强度下研究了好氧硝化段同时硝化反硝化（SND）系统的N2O排放特性,并采用PCR—DGGE技术分析微生物群落特征。结果发现,随着曝气强度的增强,系统总氮去除率下降,但脱氮中N2O—N所占比例则上升,实验中从低到高3个曝气强度下,总氮去除率分别为80．01％、65．28％和58．62％,脱氮中N2O—N所占的比例为1．89％、7．84％和9．20％。PCR—DGGE分析显示,和低曝气强度下相比中、高曝气强度下系统微生物群落发生明显变化,但中曝气强度和高曝气强度下系统微生物群落表现出较高相似性。这表明,不同曝气强度下系统N2O排放受到氮素转化和微生物群落变化的影响。适宜曝气强度不仅提高总氮去除率,还可有效控制N2O排放。     

Utilization of municipal solid waste incineration (MSWI) fly ash in ceramic brick: product characterization and environmental toxicity

In this study, municipal solid waste incineration (MSWI) fly ash was used as a blending in making ceramic brick based on its characterization and an orthogonal test was performed to determine the optimal mixture ratio of the materials. Besides, the fired bricks made in accordance with the optimal mixture ratio were characterized for performance, phase transformation, microstructure, leaching toxicity of the heavy metals in accordance with GB/T 2542-92 (Detection methods for bricks analysis, China) and by means of XRD, SEM and leaching toxicity analysis. It was found that the optimal mixture ratio of materials (MSWI fly ash:red ceramic clay:feldspar:gang sand) was 20:60:10:10 by mass, and the optimal sintering temperature was 950 °C. Leaching results of heavy metals from sintered bricks were reduced considerably in comparison with those from green bricks prior to sintering process. The results as a whole suggested that utilization of MSWI fly ash in ceramic brick constituted a potential means of adding value.     

Comparison of semi-aerobic and anaerobic degradation of refuse with recirculation after leachate treatment by aged refuse bioreactor

Two fresh refuse bioreactors (F1 and F2) were operated under semi-aerobic and anaerobic conditions, respectively. The leachate from the bioreactors F1 and F2 was introduced into the aged refuse bioreactors (A1 and A2), and the effluent from A1 and A2 was subsequently recirculated into F1 and F2, respectively. The effect of the semi-aerobic recirculation process on refuse degradation was investigated, comparing it with that of the anaerobic recirculation process. Results indicate that the semi-aerobic recirculation process can increase the accumulated net production of leachate and promote evaporation. The accumulated net production of refuse in F1 is 320 mL/kg and that of F2 is 248 mL/kg, with leachate reduction amounting to 315 and 244 mL/kg refuse, respectively. The leachate quantity reduction of semi-aerobic and anaerobic leachate recirculation process accounted for 98.4% and 98.3% of the accumulated net production of leachate, respectively. The semi-aerobic leachate recirculation process can improve the biodegradation of organic matter from fresh refuse and the reduction rate of the pollutant concentration in leachate. This should shorten considerably the time required to meet the discharge standard and the time of stabilization of the refuse as observed in the anaerobic recirculation process. It was predicted that the COD concentration of leachate from the anaerobic recirculation process would reach 1000 mg/L in the anaerobic recirculation process after 2.2 years, as for semi-aerobic leachate recirculation process it is about 100 days. Compared with anaerobic recirculation process, the semi-aerobic recirculation process is more effective on NH₃-N transformation and TN removal. The NH₃-N and TN concentration of F1 is far below those of F2 at the end of our experiment. Refuse settlement in the semi-aerobic recirculation process was faster than that in the anaerobic recirculation process. At the end of the experiment, refuse settlement ratios in the semi-aerobic and anaerobic bioreactors were 33.5% and 18%, respectively.     

光催化还原CO2的研究进展

介绍了多种将CO2转化为化工产品的光催化还原体系,包括TiO2体系、金属修饰的TiO2体系、有机光敏化剂修饰的TiO2体系和其他光敏半导体材料体系.评述了不同光催化体系的特点及其催化性能.讨论了光源波长、反应温度、CO2压力和浓度、H2O和CO2摩尔比等实验条件对反应产物种类及其产量的影响,指出催化剂的活性、光源波长和...     

废水反硝化除磷技术研究进展

结合近年来国内外最新研究成果,综述了反硝化除磷机理及工艺.重点介绍了反硝化聚磷菌的微生物学特性和除磷特性,以及不同种类的反硝化除磷工艺,并对反硝化除磷技术进行了展望.     

钠基蒙脱土对亚甲基蓝的吸附和解吸研究

采用正交实验方法,确定了钠基蒙脱土吸附亚甲基蓝染料的最佳吸附条件.采用试剂再生法、超声波法、高温焙烧法、氢氧化钠—高温焙烧结合法对钠基蒙脱土吸附亚甲基蓝进行解吸.用扫描电子显微镜照片和红外光谱对吸附前后的钠基蒙脱土的结构进行表征.实验结果表明:在亚甲基蓝溶液pH为10、吸附温度为60℃、亚甲基蓝质量浓度为1 300 m...     

防风抑尘网设计要点及参数的确定

介绍了堆场起尘、防风抑尘网抑尘的机理和国内外防风抑尘网研究结果,结合实际工程设计的经验,分析了防风抑尘网设计要点和主要参数,提出防风抑尘网设计的意见和建议。     

Effective cleanup of oil contamination on bio-inspired superhydrophobic surface

Environmental Science and Pollution Research - The oil-water separation is a popular issue and the removal of oil from bulk water is also meaningful especially in oil spill incident, which not only...     

Distribution,source, and environmental risk assessment of phthalate esters (PAEs) in water,suspended particulate matter,and sediment of a typical Yangtze River Delta City,China

Phthalates (PAEs) in drinking water sources such as the Yangtze River in developing countries had aroused widespread concern. Here, the water, suspended particulate matter (SPM), and sediment samples were collected from 15 sites in wet and dry seasons in Zhenjiang, for the determination of six PAEs (DMP, DEP, DIBP, DBP, DEHP, and DOP) using the solid-phase extraction (SPE) or ultrasonic extraction coupled with gas chromatography-mass spectrometry (GC-MS). The total concentrations of six PAEs (Σ₆PAEs) spanned a range of 2.65–39.31 μg L^?1 in water, 1.97–34.10 μg g^?1 in SPM, and 0.93–34.70 μg g^?1 in sediment. The partition coefficients (K_d1) of PAEs in water and SPM phase ranged from 0.004 to 3.36 L g^?1 in the wet season and from 0.12 to 2.84 L g^?1 in the dry season. K_d2 of PAEs in water and sediment phase was 0.001–9.75 L g^?1 in the wet season and 0.006–8.05 L g^?1 in the dry season. The dominant PAEs were DIBP, DBP, and DEHP in water and SPM, DIBP, DEHP, and DOP in sediment. The concentration of DBP in water exceeded the China Surface Water Standard. The discharge of domestic sewage and industrial wastewater might be the main potential sources of PAEs. The risk quotient (RQ) method used for the risk assessment revealed that DBP (0.01 < RQ < 1) posed a medium risk, while DIBP and DEHP (RQ > 1) posed a high environmental risk in water, DIBP (RQ > 1) also showed a high risk in sediment.