Advanced Materials Research Vols. 356-360

Abstract: Granular activated carbon (GAC) is extensively used to remove natural organic matter and residential chlorine in water treatment process of power plant. After being used, the spent GAC needs to be regenerated in order to save on operation costs and reduce solid waste disposal. In this study, microwave technique was tried to regenerate the field-spent GAC from a power plant. The effect of microwave power, irradiation time and hydrochloric acid pretreatment were investigated, it was found that microwave could recover the adsorption capacity of GAC within a short time and the tannic acid adsorption efficiency of regenerated GAC was 9 times greater than spent GAC; hydrochloric acid pretreatment could improve the regeneration process, it showed the highest removal efficiency and iodine number, 99.6% and 859 mg/g respectively. The results obtained from SEM-EDX showed that hydrochloric acid pretreatment could remove inorganic matter and other impurities of GAC. All these indicate that microwave technique can effectively regenerate field-spent GAC, and hydrochloric acid pretreatment is an important process before regeneration.

Abstract: Municipal solid waste management (MSWM) has consistently improved to keep up with the vast amount of solid waste in urban and rural areas. Research on optimization for an efficient management system has a place for the collection, transportation and transfer of solid waste. Waste transfer optimization attempts to minimize the inconvenience and costs, which must transfer between waste generation source and waste disposal sites (WDSs). In this paper, a Multi-objective Linear Programming Model for the Two-phase Waste Transfer System (MOLPMWTS) is assumed to be given, with which the two-phase waste transfer stations (WTSs) and motor carriers for waste transfer are take into account. And a two-phase waste transfer system in town of Guzhen, Zhongshan, China, is presented. The case showed a multi-objectives for numerical minimization of allocation of WTSs and transfer carriers.

Abstract: The water-based magnetic fluid (WMF) and oil-based magnetic fluid (OMF) were prepared successfully with the iron oxide spent catalyst by mechanochemical method. The iron oxide spent catalyst contains about 75% magnetite, 15% alkali metal and 10% ceria. The experimental purpose is to reclaim the spent catalyst and decrease the environment pollution. In this paper, the peculiarity of magnetic fluids was characterized by VSM, XRD, and TGA, etc. As a result, the saturated magnetizations of water-based and oil-based MFs are 22.09 emu/g and 30.02 emu/g, respectively. Their particle sizes are 15.11 nm and 16.07 nm, respectively. The prepared MFs would be used in separating low density metal from scrap, thereby decreasing the environmental pollution. Therefore, not only good magnetic fluid was prepared with the spent catalyst for the first time, but also the spent catalyst was recycled in an effective way to reduce environmental pollution.

Abstract: Based on analysis of municipal solid waste (MSW) in Shanghai city, a related integrated treatment process of MSW was studied. MSW was classified into organic, combustible, recyclable and other parts. The designed integrated treatment process includes mixed waste sorting, anaerobic digestion of the biodegradability organic waste, RDF production systems of combustible waste and deodorizing system. Organic MSW is digested under anaerobic conditions and produce biogas for power generation for electricity plant. The residue can be used to prepare organic and inorganic fertilizer; Combustible MSW has low water, high calorific value and can be prepared RDF; The recyclable trash (plastic, metal) are on sale. Other MSW is land filled. The designed integrated treatment process may provide a route to solve the problems of MSW in Shanghai.

Abstract: The microwave hydrothermal method was applied in the synthesis of Ni_0.5Zn_0.5Fe₂ O₄ ferrite nanoparticle. X-ray diffraction (XRD), infrared spectroscopy (IR) were conducted to characterize the as-prepared samples. The experiment results revealed the as-prepared nanoparticle was 8.50-10.3 nm in size with various synthesis temperatures from 40-120°C, and synthesis temperature had effects on the magnetic and adsorption properties of Ni_0.5Zn_0.5Fe₂ O₄. The saturation magnetization values increased from 22.6 to 90.8 emu g^-1 with synthesis temperature increasing. Moreover, synthesis temperature also influences the adsorption capacity of methyl orange (MO) on Ni_0.5Zn_0.5Fe₂ O₄. The as-prepared Ni_0.5Zn_0.5Fe₂ O₄ showed the highest adsorption capacity of MO in the current work when synthesis temperature was 80°C, which was contributed to the more adsorption site distributed on the nanoparticle.

Abstract: Urban sewage recycling is one of the effective ways to improve ecological environment and to alleviate water supply and demand contradiction in urban areas. This paper analyzes the utilization condition and main constraints of recycling water in China, and believes that too many quality standards for recycling water lead to complex pipe network, and another main factor restraining sewage reclamation is the shortage of buffer storage link of recycling water. The author suggests incorporating the types and standards of recycling water to simplify pipe network, decentralize the reuse and use landscape water surface as a solution for buffer storage, and combining the four feasible recycling water modes being brought forward in the practices in China.

Abstract: Taking the Weihe River in Baoji area as an example, the paper discusses the contaminants’ (counted with COD) production, treatment capacity, pollutant amount into the river, river water quality and relationship between annual water inflow distribution and river water quality in river channel. It is argued that it is impossible by relying solely on the sewage treatment to control the pollutant amount into the river and solve the river water pollution. The paper also presents that sewage reclamation is a new method to treat the river water pollution in Northern China.

Abstract: The effects of concentration of cationic polyacrylamide and pH-value on the migration rate of suspended particles have been measured by a Turbiscan Lab dispersion stability analyzer. The results showed that the migration rate of the suspended particles increases with the increase of concentration of cationic polyacrylamide between 40 and 70mg/L and decreases with the increase of its concentration between 70 and 90mg/L. The migration rate of suspended particles decreases with increasing pH-value or settling time.

Abstract: In this study, the indicators assimilable organic carbon (AOC), dissolved organic carbon (DOC), heterotrophic plate counts (HPC) and microbially available phosphorus (MAP) were measured to evaluate the biological stability of drinking water in Jinan, an east China city, which uses different water sources in its distribution system. The results were shown that the concentration of AOC below 50μg ac-C•L-1 covered the detection of 58% sampling points in the city distribution systems. The difference of source water exercised a great influence to the concentration of AOC. The lower heterotrophic colony counts were detected when the AOC values were higher, and vice versa. The value of AOC/DOC showed its irregularity. MAP was negatively correlated with the AOC. Higher values of AOC and HPC were detected in pumping water than that in pipe water, while values of MAP were equivalent to each othe

Abstract: In order to study the effect of dilation angle ψ to the stability of slope, a numerical model was founded in plane strain mode by FLAC3D for homogeneous soil slope. The safety factors and slip planes were obtained for different dilation angles, and the relationships of dilation angle, safety factor and slip plane were analyzed for different situations with and without load on the top surface.