Impacts of climate change in rapidly urbanizing region-a case study in Hangzhou(China)

Climate change is expected to be a major driving force of landscape in the coming decades.It will have a multitude of potential impacts that vary in intensity and effect according to region and sector.In the context of global warming,the climate of China has changed significantly in the recent 100 years.The reason for climate change in China is mainly due to irrational land use caused by human activities,which chiefly results in the rapid industrialization and urbanization process.Based on an assessment model,this research represents a picture of the impacts of climate change in six districts of Hangzhou region.The aim of this paper is to conclude,on the one hand,some of Hangzhou sensitivities in relation to the primary effects of climate change.On the other hand,a reflection is made on a methodology to formulate preconditions on a scientific basis for further research by design of integrated adaptation options for the future spatial developments in function to upgrade Hangzhou resilience in relation to climate change challenges.     

Toxicity of sediment cores from Yangtze River estuary to zebrafish (<Emphasis Type="Italic">Danio rerio</Emphasis>) embryos

Toxicity evaluation is an important segment in sediment quality monitoring in order to protect aquatic organisms and human health. The purpose of this study is to assess the toxicity of sediments from three sediment cores in Yangtze River Estuary, China, using the zebrafish (Danio rerio) embryo tests. Fertilized zebrafish eggs were exposed to both whole sediments and sediment organic extracts prepared from collected sediments, in order to provide a comprehensive and realistic insight into the bioavailable toxicity potential of the sediments. As end points, development parameters (mortality, hatching rate, and abnormality) in the developing embryos were recorded during the 96-h exposure. The results showed that some samples increased mortality, inhibited the hatching of embryos, and induced morphological abnormalities. The embryonic toxicities presented serrated changes and irregular distribution with depth, which may be related to hydrodynamic effect and unstable environmental input. However, lethal and sub-lethal effects were more significant at the sub-surface sediments (10～40 cm), which indicated that the pollution is more serious in recent decades.     

纳米TiO2-石墨烯光催化剂的水热合成及其光催化性能

以钛酸四正丁酯和石墨为原料,通过水热法制备了锐钛矿型为主的纳米TiO2复合光催化剂（纳米TiO2-石墨烯）,并采用XRD,FTIR,FESEM,TEM技术对其进行了表征。通过紫外光照射降解溶液中的罗丹明B（RhB）研究了TiO2-石墨烯的光催化活性,分析了初始罗丹明B质量浓度、催化剂加入量、溶液pH和催化剂使用次数等影响降解效果的因素。实验结果表明：在初始RhB质量浓度为20 mg/L、溶液pH为7.10、催化剂加入量为1.000 g/L的条件下,紫外光照射30 min时,纳米TiO2-石墨烯对RhB的降解率高达98.69%,明显高于纳米TiO2的44.69%;纳米TiO2-石墨烯稳定性较强,可多次重复使用。     

Optimizing Cr(VI) adsorption on activated carbon produced from heavy oil fly ash

In order to explore the beneficial utilization of heavy oil fly ash (HOFA) generated in the power plants, the present study is intended to optimize the chromium(VI) [Cr(VI)] adsorption on activated carbon produced from HOFA. The raw HOFA obtained from a power plant was washed by nitric/hydrochloric acid and activated at 800 °C with a holding time of 60 min to produce fly ash activated carbon (FAC). Phosphoric acid was used as a chemical agent to improve the surface characteristics of the HOFA during the activation process. Batch adsorption experiments were employed to evaluate the effects of different parameters such as initial Cr(VI) concentration, pH, and FAC dose on the removal of Cr(VI) from aqueous solution. A total of 17 adsorption experimental runs were carried out employing the detailed conditions followed the response surface methodology based on the Box–Behnken design. The results indicate that developed FAC has the potential for removing Cr(VI) from wastewater. Under the test conditions, a maximum of 91.51 % Cr(VI) removal efficiency was achieved.     

Biodegradation of beta-cypermethrin by a novel Azoarcus indigens strain HZ5

A novel strain HZ5 was isolated from the activated sludge of a pesticide manufacturer in Hangzhou, which was capable of degrading beta-cypermethrin (beta-CP). Based on its physiological characteristics and analysis of 16S rDNA gene, strain HZ5 was identified as Azoarcus indigens, which was a new genus that can degrade beta-CP effectively. Strain HZ5 could degrade beta-CP over a wide range of temperature (20 to 40°C) and pH (5.5 to 9.0), and the optimal temperature and pH were 30°C and 7.0. The highest degradation rate was approximately 70% of 50 mg/L beta-CP within 144 h at pH 7.0 and 30°C in MSM. An additional carbon source could enhance the biodegradation of beta-CP. Studies on biodegradation of the beta-CP showed no significant enantioselectivity. During the process, two main intermediate metabolites were produced by strain HZ5 and determined as 3-phenoxybenzaldehyde and 3-phenoxybenzoic acid by gas chromatography-mass spectrometry (GC-MS) analysis. The results indicated that strain HZ5 may have potential application in bioremediation of beta-CP polluted environment.     

Influences of adding easily degradable organic waste on the minimization and humification of organic matter during straw composting

To find a better composting process with low greenhouse gas emission and high humus production, the effect of adding kitchen waste on reduction and humification of organic matter during straw composting was studied. Three processes were compared, consisting of different ratios of straw and kitchen waste (1:2, 1:1, and 2:1). At four time points over a 62-d incubation, the reduction and humification of compost was evaluated by measuring the total mass, carbon content, and humic material content of the compost. Treatment 1 (straw/kitchen waste ratio of 1:2) reduced the total mass of compost the most. Treatment 2 (straw/kitchen waste ratio of 1:1) reduced the total carbon content the most, reflecting the highest emission of greenhouse gas. Treatment 3 produced the most humic acid material and released the lowest amount of carbon. Hence, from the point of view of reducing greenhouse gas emissions and increasing stable organic matter such as humus and humic acid during composting, treatment #3 was optimal. The three treatments resulted in significant differences in microbial biomass and enzyme activity during composting. The highest amount of active microbial biomass was associated with the largest reduction in compost mass (treatment 1). Higher proportions of straw (treatments 2 and 3), which contains more lignin, were associated with greater β-glycosidase activity, which may generate more humus that can improve soil quality. Dehydrogenase activity seemed to be the most important microbial factor in organic carbon catabolism or humification.     

The Reuse of Biosludge as an Adsorbent from a Petrochemical Wastewater Treatment Plant

Abstract

Biosludge was obtained from a petrochemical industry’s biological wastewater treatment plant. Zinc chloride (ZnCl₂) was used as a sludge activation agent during the pyrolytic process. Scanning electron microscope (SEM) image photographs, element composition, surface functional group, and pore structure were analyzed for the sludge adsorbent characteristics. Results indicated the proper ZnCl₂-immersed concentration, pyrolytic temperature, and time could produce adsorbent from the bio-sludge. The optimal conditions for a larger surface area adsorbent were 3 M ZnCl₂-immersed sludge pyrolyzed at 600 °C for 30 min and washed with 3 N hydrochloric acid (HCl) solution and distilled water. The predominant pore size of the sludge adsorbent was the mesopore.     

Decomposition of SF6 in an RF Plasma Environment

Abstract

Sulfur hexafluoride (SF₆)-contained gas is a common pollutant emitted during the etching process used in the semiconductor industry. This study demonstrated the application of radio-frequency (RF) plasma in the decomposition of SF₆. The decomposition fraction of SF₆ [η_SF6 (C_in–C_out)/C_in x 100%] and the mole fraction profile of the products were investigated as functions of input power and feed O₂/SF₆ ratio in an SiO₂ reactor. The species detected in both SF₆/Ar and SF₆/O₂/Ar RF plasmas were SiF₄, SO₂, F₂, SO₂F₂, SOF₂, SOF₄, S₂F₁₀, S₂OF₁₀, S₂O₂F₁₀, and SF₄. The results revealed that at 40 W, η_SF6 exceeded 99%, and the reaction products were almost all converted into stable compounds such as SiF₄, SO₂, and F₂ with or without the addition of oxygen. Sulfur oxyfluorides such as SO₂F₂, SOF₂, SOF₄, S₂OF₁₀, and S₂O₂F₁₀ were produced only below 40 W. The results of this work can be used to design a plasma/chemical system for online use in a series of a manufacturing process to treat SF₆-containing exhaust gases.     

Hydrothermal treatment for inactivating some hygienic microbial indicators from food waste–amended animal feed

To achieve the hygienic safety of food waste used as animal feed, a hydrothermal treatment process of 60–110 °C for 10–60 min was applied on the separated food waste from a university canteen. Based on the microbial analysis of raw waste, the inactivation of hygienic indicators of Staphylococcus aureus (SA), total coliform (TC), total aerobic plate counts (TPC), and molds and yeast (MY) were analyzed during the hydrothermal process. Results showed that indicators' concentrations were substantially reduced after hydrothermal treatment, with a greater reduction observed when the waste was treated with a higher temperature and pressure and a longer ramping time. The 110 °C hydrothermal treatment for 60 min was sufficient to disinfect food waste as animal feed from the viewpoint of hygienic safety. Results obtained so far indicate that hydrothermal treatment can significantly decrease microbial indicators' concentrations but does not lead to complete sterilization, because MY survived even after 60 min treatment at 110 °C. The information from the present study will contribute to the microbial risk control of food waste–amended animal feed, to cope with legislation on food or feed safety.

Implications: Reduction of microbial indicators at ramping time and holding time during the hydrothermal process showed that hydrothermal treatment is an effective method to achieve hygienic feed from food waste to a certain extent, but the conditions researched in this study were not enough for the complete sterilization of food waste, because of the different heat resistance of bacteria and spores.     

Understanding world metals prices—Returns,volatility and diversification

In recent times, the prices of internationally traded metals have reached record highs and there is considerable uncertainty regarding their future. This phenomenon is partially driven by strong demand from a small number of emerging economies, such as China and India. This paper uses a long time-series (1900–2007) on 21 metals prices to investigate their properties, and presents unique features of their volatility, including a decomposition into within- and between-group components. If most volatility is commodity-specific rather than “global”, then metals-exporting dependent economies can smooth income via diversification.