Applied Mechanics and Materials Vol. 700

Abstract: The various affecting factors have been researched in this paper that the leaded wastewater was treated by means of the processing combined Fe-C micro-electrolysis with microbial adsorbent-flocculant. After that combined process, a greater percentage of lead removal was observed. The results showed that under the condition that initial PH of the infall wastewater is 3, the Fe/C mass ratio is 2:1, and the hydraulic retention time is 40 min for the micro electrolysis processing. The PH is 9, the microbial adsorbent-flocculant (ZX-1) dosage is 0.5g/L, and adsorption time is 90 min for subsequent microbial adsorption-flocculation. Under these optimal conditions, the removal rates of lead ion reached 99.958%,and their concentrations in wastewater were 0.042mg/L, which their ion concentrations in the outlet wastewater are under the class III of Surface Water Quality Standards(GB3838-2002) in China. That combined process achieved zero discharge of lead. It has been also showed that Pb ions are mainly removed by Fe/C micro-electrolysis, and the following microbial adsorption-flocculation excels at treating leaded wastewater of low concentration.

Abstract: Heavy metals (Hg, As, Pb, Cd, Cr, Cu) pollution in soil samples of Rosa sterilis planting areas located in Wudang District in Guiyang and Pingba County in Anshun was studied using a new evaluation theory of pollution loss rate, and following a series of methods for Rosa sterilis leaf including over standard rate, enrichment coefficient, single pollution index and comprehensive pollution index, the heavy metals pollution of the two Rosa sterilis planting areas was analyzed and evaluated. The results showed that the soil comprehensive pollution loss rate ranged from 12.73% to 28.26% in Wudang District samples, most of which belong to light pollution level. The comprehensive soil pollution loss rate of the sampling points in Pingba County varied from 9.68% to 16.10%, which belong to fairly clean level. Meanwhile, the experimental results for the Rosa sterilis leaf showed that the contents of Cr and Pb in both planting areas exceeded the permissible limit, while other elements were below the safe limit. The six heavy metal elements in Rosa sterilis leaf did not accumulate.

Abstract: In this paper,europium doped zinc oxide nanoparticles were prepared by Zn (CH₃COO)₂, Eu (NO₃)₅·6H₂0,NaOH,PEG2000 and Citric acid using hydrothermal method. The prepared powder was used for photocatalytic degradation, in which the influence ofreaction temperature, reaction time, illumination conditions as well as the doping ratio on the effect of photocatalytic oxidation were throughly investigated. Analytical methods, such as XRD, SEM and EDS were utilized in this study for characterization of the prepared powder. Results showed that Europium-doped zinc oxide with a 3% doping ratio reached optimal photocatalytic oxidation effect when the hydrothermal temperature was 160°C and hydrothermal time was 6 hours. By utilizing the prepared powder under optimal conditions, the decolorization rate of pharmaceutical wastewater reached 38.8% after treatment of 365nm UV irraditation for 150min, and the degradation rate of COD reached 57.5%.

Abstract: Phytoextraction of heavy metal polluted environment generates large quantities of hyperaccumulators. How to dispose hyperaccumulators safely has been one of the most important issues in the phytoextraction field. In this paper, incineration technology was studied in order to investigate the feasibility of incineration technology on disposal of the arsenic-containing hyperaccumulator Pteris vittata L.. The tube furnace experiment examined the changes of arsenic in Pteris vittata L., studied the effects of factors including temperature, time, percentage of CaO on the incineration state. The results show that the most appropriate incineration condition was temperature of 400°C, time of 30min, percentage of CaO of 10%, which solved the problem to reduce biomass of Pteris vittata L. and volatilization of arsenic. The result provide insight into developing harmless disposal or resource-reuse-oriented methods for disposal of the plants used for large scale phytoremediation application.

Abstract: This paper presents a quantitative risk assessment study on a Floating, Production, Storage and Offloading Vessel that operate in Brazilian offshore oil and gas production waters. In particular a study of the risks applied to a Storage Unit and Transfer Oil, focusing on the physical, especially in operations involving storage and handling of flammable liquids. The results showed that the unit must take safety measures process, because a failure in the system can affect other units; the level of security for the population of the ship is within the acceptable.

Abstract: The Yellow River delta is the Lord area of national high efficient ecological-economic region and Shandong peninsula blue economic region, and it has an important strategic status. This paper integrates variable fuzzy set theory with geographic information technology (GIS) to construct the vulnerability evaluation model of Yellow River delta water resources. First, The study area is partitioned into different evaluation zones (sub-area) based on the spatial recognition technology of GIS; Second, the evaluation index system is formulated in terms of the two aspects of water resources vulnerability, natural and human factors; Finally, city of Dongying is selected as study area, which accounts for 93% of the Yellow River delta, to verify the proposed model. The results indicate that the water resources vulnerability of the Yellow River delta greatly changes in space, the region of coastal, Xiaoqing river and Zhimai river shows high vulnerability, while the region along the Yellow River has low vulnerability. In conclusion, the proposed model can effectively identify water resource vulnerability in space.

Abstract: Due to the influences of climate change and human activities, the water and sediment flux of the Yellow River are certainly changing. This paper selects monthly time series of runoff and sediment flux from 1950 to 2009 for study at Lijin station, in lower Yellow River. A widely used identification method, wavelet analysis, is applied for recognizing changing point and cycle of the runoff and sediment respectively in multi-scale of annual, flood season and non-flood season. The results indicate that there are two significant changing points in 1985, 2002 year, and cycle recognized results are different in multi-scale as well as with different hydrology factors.

Abstract: Based on the increasingly harsh climate change and water scarcity in China, the seawater desalination is gradually becoming one of the important alternatives to solve the problems of water shortage. This paper makes a comparison among various technologies for seawater desalination and forecasts the development direction and the advanced desalination process merged with other green energy techniques.

Abstract: Oxidant flushing of the raw water distribution system (RWDS) affects the degradation of dissolved organic matter (DOM). The characteristic of DOM after chlorine (NaOCl), chlorine dioxide (ClO₂) and their combination (NaOCl/ClO₂) were evaluated by dissolved organic compound (DOC), spectrophotometry and fluorescence of DOM in simulated RWDS. The results suggested that oxidant flushing had negative effect on DOC removal, especially for NaOCl/ClO₂, but it was resumed with a higher recovery rate compared to ClO₂ and NaOCl. The biodegradable of DOM increased after oxidant flushing, and related to DOC degradaion. Overall fluorescence of DOM intensity has a decrease potential after oxidant flushing, particularly for tryptophan-like fluorescence. These results indicated that NaOCl/ClO₂ has less negative impact on the resume of DOM degradation in RWDS compared with corresponding single oxidant.

Abstract: Underground water is directly used as drinking water in most rural areas of developing countries due to limitations in infrastructure. As an important indicator of drinking water quality, however, microbial quality has been largely ignored for a long time. Microbial quality poses a great threat to the safety of underground drinking water, especially in rural areas. The current study compared microbial abundance and community structure of three different water sources, i.e. underground water, Poyang Lake and Hai River, combined with flow cytometry (FCM) and denaturing gradient gel electrophoresis (DGGE). FCM results showed that the bacterial concentration of underground water is the lowest (1.037×10⁶ cell/ml) of the three water sources, but still approximates that of the Poyang Lake. The removal rate of bacteria after filtration through a 0.45μm-pore-size filter is 98.16% in underground water. The removal rate for Poyang Lake and Hai River is much lower (i.e. 66.57% and 74.17% respectively). DGGE profiles demonstrated that the microbial community structure in underground water shares higher similarity to Poyang Lake (51.0% and 53.1% similarity for bacteria and fungi respectively) than Hai River. The microbial diversity index (i.e. Shannon-Weaver index) for bacteria and fungi are 2.906 and 2.847 respectively in underground water, which is lower than in Poyang Lake. The evenness (i.e. Simpson index) of groundwater was lowest among the three water sources tested. The results suggested that groundwater has a complex microbial community and hence it is critical to apply necessary hygienic barriers to remove microbes for the safety of underground drinking water.