Urban garbage disposal and management in China

This paper, probing into the present situation of urban domestic garbage by analyzing its growing trend, compositional change and regional difference, reveals the problems existing in its disposul and management in China. Meanwhile, a questionnaire was conducted in five big cities around China for surveying urban residents‘ attitudes towards garbage disposal and management policies and measures. Results showed the outlmt of urban domestic garbage in Chinese cities is ever increasing, and the recoverable materials and energy in garbage composition are also increasing. The population growth, economic development, and increase of residents‘ expenditure level are the main factors influencing the growing output and changing composition of the garbage. Information acquired from the questionnaire showed that majority of the urban residentsare in favor d the garbage reduction policies and managerial measures and are willing to collaborate with municipal government in battling against gadbage. Based on the analysis and questionnaire, some policymaking-oriented suggestions such as operating the garbage disposal from a social welfare service to a sector of profit-gaining enterprises, transferring the garbage management from passive end control to active source control,promoting the classified garbage collection in cities around China, and charging garbage fees for its cleanup and disposal, have also been put forward in the paper.     

收缩情境下城市土地利用及其生态系统服务的研究进展

随着国际国内社会经济环境的变化,城市收缩这一新现象逐渐在我国部分城市区域空间中呈现,成为未来新型城镇化转型的挑战之一。在简要梳理城市收缩相关文献的基础上,以土地利用为主线,重点关注收缩情景下的土地利用模拟及其政策、空置土地与城市生态系统服务等方面的相关研究。研究结果表明：（1）当前对城市收缩问题的研究主要集中于人口变动和经济发展维度,对由此引发的土地利用以及生态系统变化关注较少。（2）土地利用模拟在分析和预测收缩情境下的城市土地利用变化上具有较大价值,但不同模型适用于不同研究情景,复合模型将具有更好的解释力。（3）土地利用政策的制定和实施应充分考虑经济社会各方面诉求,绿色空间存储制度是促进收缩城市可持续发展的有力措施。（4）城市收缩产生的空置土地为发展生态系统服务提供了空间,应发展适用于我国城市收缩的生态系统服务评估方法。在我国城镇化进入“存量模式”甚至“减量模式”的背景下,应加大对城市收缩情景下土地利用和生态系统维度的研究,要积极借鉴并整合资源科学、地理学、生态学、管理科学和城市规划等相关学科的研究方法,并紧密结合我国当前城市发展和空间规划所面临的现实问题,促进城市收缩研究的方法创新和收缩城市的可持续发展。     

湿地综合分类研究:Ⅱ.模型

在前文［１］提出的湿地综合分类方法的基础上，进一步探讨用状态变量描述湿地状态特征和动力特征的途径。重点讨论建立反映湿地状态变量间制约关系的湿地动力模型。这一工作是湿地综合分类的主要目的所在，是综合分类研究的自然延伸，同时也是实现对湿地系统定量描述的有益尝试。     

大气颗粒物中多环芳烃的监测

本文报导了大气颗粒物中多环芳烃的一种测定方法和结果。颗粒物预处理方法是:超声萃取,抽滤,减压蒸发浓缩,硅胶柱净化,再浓缩,定容溶解。用高效液相色谱法分离和鉴定。对西南石油学院5个功能区冬季大气颗粒物中的苯并(a)芘等9种多环芳烃的分布状况进行了实测,苯并(a)芘平均含量为26ng/m~3,为国外一些大城市冬季值的三倍,为国内一些大城市冬季污染值的二分之一。     

氯代芳烃催化氢转移脱氯的研究

本文以甲酸钠为氢源,对聚乙烯吡咯烷酮锚定的ＰｄＣｌ２催化氯代芳烃脱氯进行了研究,考察了反应条件对反应的影响,研究了脱氯的选择性。结果表明;该方法具有卓越的脱氯选择性,催化剂用量少,反应条件温和,操作简便。本文并对其脱氯反应机理进行了初步探讨。     

北亚热带过渡区土壤的模糊聚类分析

本文阐述了北亚热带过渡区十个土壤剖面的成土条件和基本性质，应用模糊聚类对土壤的五项诊断指标进行了分析，并与发生分类和诊断分类相比较．在中国土壤系统分类中提出建立淋溶土纲和始成土纲的基础上，探讨了供试土壤的分类地位。其中０１－０４号剖面属于典型铁质湿润淋溶上亚类；０５—０７和０９号剖面归为铁质粘磐半干润淋溶土亚类；０８号剖面为典型半干润淡色始成上亚类，１０号剖面为典型淡色滞水淋溶士亚类。     

Dynamics of PCDDs/DFs and coplanar-PCBs in an aquatic food chain of Tokyo Bay

Concentrations and accumulation profiles of PCDDs/DFs and coplanar-PCBs (co-PCBs) in aquatic biota (e.g., plankton, shellfish, benthic invertebrate, and fish) and sediment from Tokyo Bay were examined to elucidate the relationship between bioaccumulation and trophic level in the food web as determined by the stable nitrogen isotope analysis. Bioaccumulation patterns of PCDDs/DFs and co-PCBs varied greatly among congeners. Accumulation patterns of PCDDs/DFs and co-PCBs are not solely explained by their physicochemical properties. Biota-sediment accumulation factors (BSAFs) for co-PCBs in biota from Tokyo Bay were significantly greater than those of PCDDs/DFs. Furthermore, the slopes of the plots of delta15N and BSAF values and water solubility of 2,3,7,8-substituted PCDDs/DFs and co-PCBs were highly correlated. The results of our study would provide the valuable information to understand the accumulation properties of PCDDs/DFs and co-PCBs that can be used as a scientific basis to determine the sediment quality criteria of PCDDs/DFs and co-PCBs.     

Induction of the P450 reporter gene system bioassay by polycyclic aromatic hydrocarbons in Ulsan Bay (South Korea) sediments

Polycyclic aromatic hydrocarbons (PAHs) and induction of the P450 reporter gene system (RGS) for 6- and 16-h exposure periods were determined in organic extracts of Ulsan Bay (South Korea) sediments to assess the utility of this bioassay as a screening tool for PAH contamination. The sum of the concentrations of 23 individual PAHs in 30 sediment samples (sigma PAH) based on GC-MS analysis ranged from 0.05 to 6.1 micrograms/g dry wt. P450 RGS fold induction ranged from 4.0 to 320 micrograms/g based on benzo[a]pyrene toxic equivalents (BaPEq). P450 RGS BaPEq and the 'chemical BaPEq', defined as the sum of the products of individual PAH concentrations and pre-determined toxic equivalency factors, exhibited very strong positive correlations with sigma PAH (r2 > 0.90; P < 0.001). Fold induction did not increase (and in some cases decreased) after the optimal incubation period (6 h) for PAHs, indicating that other compounds known to induce the P450 RGS (e.g. chlorinated organics) were not present at levels effecting significant induction. This was supported by GC-ECD analysis where non-ortho and mono-ortho polychlorinated biphenyls (PCBs) known to be strong P450 RGS inducers were found to be at very low or non-detectable levels in samples with the highest P450 RGS responses. The profound difference in PAH profiles for the two most contaminated sites suggested that this assay is especially sensitive for selected PAHs with greater than four rings. Combined with previous results, the P450 RGS shows promise as a useful screening tool for predicting deleterious biological effects resulting from CYP1A1-inducing, sediment-associated chemicals, particularly high molecular weight PAHs.     

Decolorization of textile wastewater by photo-fenton oxidation technology

This paper describes the use of photo-fenton process for color removal from textile wastewater stream. The wastewater sample to be treated was simulated by using colorless polyvinyl alcohol (PVA) and reactive dyestuff of R94H. As a result, the hydroxyl radical (HO*) oxidation can effectively remove color, but the chemical oxygen demand (COD) was removed in a slight degree. The color removal is markedly related with the amount of HO* formed. The optimum pH for both the OH* formation and color removal occurs at pH 3-5. Up to 96% of color can be removed within 30 min under the studied conditions. Due to the photoreduction of ferric ion into ferrous ion, color resurgence was observed after 30 min. The ferrous dosage and UV power affect the color removal in a positive way, however, the marginal benefit is less significant in the higher range of both. PVA as the major background COD of a textile wastewater stream inhibits the color removal insignificantly as its concentration increases.     

Behaviors of intercellular materials and nutrients in biological nutrient removal process supplied with domestic wastewater and food waste.

A four-stage biological nutrient removal (BNR) process was operated to investigate the effect of anaerobically fermented leachate of food waste (AFLFW) as an external carbon source on nutrient removal from domestic wastewater having a low carbon-to-nitrogen ratio. The BNR system that was supplemented with AFLFW showed a good performance at a sludge retention time (SRT) of 30 days, despite low temperature. With this wastewater, average removal efficiencies of soluble chemical oxygen demand (COD), total nitrogen (T-N), and total phosphorus (T-P) were 88 to 93%, 70 to 74%, and 63 to 68%, respectively. In this study, several kinds of poly-hydroxyalkanoates (PHAs) were observed in cells. These included 24% poly-3-hydroxybutyrate (PHB), 41% poly-3-hydroxyvalerate (PHV), 18% poly-3-hydroxyhexanoate (PHH), 10% poly-3-hydroxyoctanoate (PHO), 5% poly-3-hydroxydecanoate (PHD). and 2% poly-3-hydroxydodecanoate (PHDD), indicating that microorganisms could store various PHAs through the different metabolic pathways. However, breakdown of the enhanced biological phosphorus removal (EBPR) mechanism was observed when SRT increased from 30 to 50 days for the enhancement of nitrification. To study the effect of SRT on EBPR, a sequencing batch reactor (SBR) system that was supplied with glucose was operated at various SRTs of 5, 10, and 15 days. Nitrification and denitrification efficiencies increased as SRT increased. However, the content of intracellular materials such as PHAs, glycogen. and poly-P in cells decreased. From these results, it was concluded that SRT should be carefully controlled to increase nitrification activity and to maintain biological phosphorus removal activity in the BNR process.