Study on Residential Water Use in North China:Analysis of Nationwide Statistical Data and Case Study of Taiyuan City

Residential water use is gradually becoming the focus in China‘s municipal water supply planning and management in recent years. Little is known, however, about the residential water use in modem China due to the transition of economy and enhancement of management on water conservation. In order to better understand the characteristics of residential water use in North China, a model for identifying the determinants of residential water use was established and analyzed by using panel data and cross-section data methodologies. Then Taiyuan city, the capital city of Shanxi Province in Northern China was selected as a case study. Both the analyses and field investigation indicate that the relatively slow increase of residential water use in recent years may result from the implementation of strict laws and regulations on water conservation. And through the investigation,first-hand information about water consumption pattern, water reuse/conservation, people‘s attitude toward water quantity and quality, etc. have been obtained.     

Efficiency and Economy of a New Agricultural Rainwater Harvesting System

Shortage of water is the key limiting factor for agricul-tural development of Beijing. Rainwater harvesting (RWH) could provide an alternative water source for greenhouse agriculture, but local natural and socioeconomic conditions challenge the applica-tion of the technology. This article analyses the advantages and disadvantages of different types of greenhouse RWH in Beijing,and describes a new greenhouse RWH system demonstrated in 2008 in Huairou, a suburb district of Beijing. It analyses the ef-ficiency, cost-benefit ratios and limiting factors of the new system.The results show that with the new system, RWH efficiency can be as high as 66% (of total rainfall) and the rainwater usage rate can reach 69% of total water usage. The ratio of benefit to cost of government investment can be 1.84, and the ratio of benefit to cost of a farmer's investment could be 1.68 provided the project is designed to save water and also increase income. However, the price of groundwater for agriculture directly influences the potential for applying and scaling up the project. If the RWH system does not increase the farmers' incomes at the current water price, they will not use it until the water price rises to a critical point, which is de-termined by external factors. This article also suggests a number of measures to increase the efficiency of the system in order to apply it on a large scale.     

区域二氧化硫控制优化模型研究

传统的区域二氧化硫控制优化都是基于损害函数法和环境标准化法的。本文在分析比较了传统二氧化硫污染控制战略优化中的损害函数法和环境标准化法各自的优点与局限的基础上。建立了基于时间序列决策的整数规划优化模型。这一理论模型更好地描述了控制战略实施的过程。把时间作为模型优化的一个因子。这种基于时间序列的过程充分考虑了货币的时间价值。并能分析这些时间价值对二氧化硫污染控制战略的动态过程影响。本文的模型是更加符合现实的情况。它对于区域二氧化硫控制的中长期决策优化显得更为有效和准确。     

长江口横沙附近河势变化与可利用港航资源分析

以1998/1999年长江流域洪水后奠定的河口河势为参照,利用四期大比例尺海图,数字化分析了1998/1999～2011年长江口北港河势与横沙东滩演变,讨论了北港和横沙东滩受河口重大工程影响产生的新变化。结果表明：青草沙水库工程稳定了北港河势;依托深水航道导堤工程和圈围工程,横沙东滩快速淤长,至2011年,-2 m、-5 m以上面积分别达到304 km2、522 km2,扣除深水航道坝田区面积,还有237 km2、450 km2;围绕横沙岛和横沙东滩,北岸可利用-10 m岸线达到16 km,在未来的7~23 a,可为上海的发展提供大量的新增岸线资源和土地资源。横沙北靠北港,南依长江口深水航道,东临东海;吹填成陆的横沙东滩土地资源丰富,经济地理位置优越,使得在横沙建设上海新港区成为可能     

三峡库区农田面源污染典型区域制图及其研究现状评价

利用GIS空间叠加分析方法,通过遴选影响库区农田面源污染关键因子,获得了3大类8小类库区农田面源污染典型区,从空间分布格局的角度对这些典型区做了深入的比较分析,并提出土壤类型是导致不同典型区分布差异的主导因素。在此基础上,对国内外已在库区内开展农田面源污染研究工作的相关研究区进行了典型性分布现状评价,研究认为：(1)目前针对“紫色土-旱地-林地-水田”农田面源污染典型区的研究区设置较完善,在整个库区中的分布格局也较合理,有利于相关研究成果在该区推广应用;(2)对“黄壤-旱地-林地”典型区研究较少,无法满足整个库区尺度下的应用需求,需加强对库区中部和库尾相关区域的研究区配置;(3)由于对“石灰(岩)土-林地”典型区的研究缺失,亟需开展该区内农田面源污染研究工作。研究获得的不同类型典型区分布图可为相关研究区的选择提供必要的决策依据。此外,研究虽只是针对农田面源污染开展了典型区制图分析,但研究方法具有一定的推广性,在必要数据支持下,可应用于三峡库区或其他区域农业面源污染典型区制图研究     

真空膜蒸馏和膜吸收及其集成工艺处理高氨氮废水

采用PP中空纤维膜组件,对VMD(真空膜蒸馏)和MA(膜吸收)脱氨过程进行了研究。考察了料液pH值(9.0~11.0)、料液进口温度(20~50℃)对脱氨效率的影响。研究结果表明,VMD和MA脱除率分别达85%和99%以上。料液pH和料液进口温度对VMD脱氨效果的影响较大,提高料液pH和进口温度可以明显提高VMD的脱氨效率;料液pH对MA的脱氨效率影响较为显著。对2种膜工艺进行了技术集成,利用该集成工艺可达到99.96%以上的氨去除率,出水可达标排放,并且可以有效防止硫酸铵的二次污染。     

夏季局地环流对京津冀区域大气污染影响

为研究局地环流对京津冀大气污染分布特征的影响,利用京津冀区域大气污染监测网7个站点的大气污染物浓度观测资料,结合WRF数值模式对气象场的模拟结果,对区域夏季局地环流对大气污染浓度水平和空间分布特征进行了研究。结果表明,2010年6月局地环流发生时,京津冀大气中PM10的平均浓度可高达156.4 μg/m3,而在强天气系统过境时仅为89.1 μg/m3。京津冀受区域局地环流控制时,大气中可吸入颗粒物比强天气系统过境时高75%;海-陆风回流携带的高浓度污染物,导致海滨区域夜间大气中PM10平均浓度从46.2 μg/m3上升到64.7 μg/m3;山地-平原风导致京津冀大气本底区域河北兴隆臭氧浓度峰值较北京城区滞后3 h。京津冀近年来强天气过程比例逐渐下降,目前仅占月20%,而以山地-平原风和海-陆风叠加的局地环流气象条件占比增加,造成京津冀区域大气污染易聚难散。     

Photocatalytic decomposition of N<Subscript>2</Subscript>O over g-C<Subscript>3</Subscript>N<Subscript>4</Subscript>/WO<Subscript>3</Subscript> photocatalysts

Although the nitrous oxide belongs among three of the most contributing greenhouse gases to global warming, it is quite neglected by photocatalytic society. The g-C₃N₄ and WO₃ composites were therefore tested for the photocatalytic decomposition of N₂O for the first time. The pure photocatalysts were prepared by simple calcination of precursors, and the composites were prepared by mixing of suspension of pure components in water followed by calcination. The structural (X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy), textural (N₂ physisorption), and optical properties (diffuse reflectance spectroscopy, photoluminescence spectroscopy, photoelectrochemical measurements) of all composites were correlated with photocatalytic activity. The experimental results and results from characterization techniques confirmed creation of Z-scheme in the WO₃/g-C₃N₄ composites, which was confirmed by hydroxyl radicals’ trapping measurements. The photocatalytic decomposition of N₂O was carried out in the presence of UVA light (peak intensity at 365 nm) and the 1:2 WO₃/g-C₃N₄ composite was the most active one, but the photocatalytic activity was just negligibly higher than that of pure WO₃. This is caused by relatively weak interaction between WO₃ and g-C₃N₄ which was revealed from XPS.     

DNA磁性纳米颗粒对水中菲的吸附性能

多环芳烃(polycyclic aromatic hydrocarbons, PAHs)作为一种致癌污染物,在水体中分布广泛且容易在生物体内富集,对人体健康有着严重的威胁。本研究将DNA与磁性纳米颗粒结合作为吸附剂,利用DNA与多环芳烃化合物的嵌入结合原理去除水体中的菲,分别考察了时间、菲的初始质量浓度、温度等因素对DNA结合菲的影响,以及对DNA磁性纳米颗粒去除菲的影响。结果表明：在35 ℃、pH=7.4、时间为50 min的条件下,在DNA的质量浓度为0.1 mg∙mL⁻¹、菲的初始质量浓度分别为150、200、250 μg∙L⁻¹时,结合率分别为95.47%、93.46%、91.14%。在相同条件下,DNA磁性纳米颗粒用量为1 mg、菲的初始质量浓度分别为100、150、200、250 μg∙L⁻¹时,去除率分别为96.47%、95.61%、93.46%、88.03%,吸附量分别为96、143、187、220 μg∙g⁻¹。DNA磁性纳米颗粒对菲的吸附过程符合准二级动力学模型和Langmuir模型,热力学参数表明吸附过程是自发和吸热的。DNA磁性纳米颗粒作为吸附剂可用于去除污水中的菲,以上研究结果可为基于PAHs-DNA嵌入结合作用处理污水中的菲提供参考。     

我国污水资源化的现状分析与对策探讨

本文简述了国内外污水资源化的历史与现状、污水资源化常规技术及深度污水处理技术的发展与前景展望。对中水回用工程进行了技术经济分析,探讨了工业废水回用的可行性。提出了在我国进一步推广污水资源化措施的对策