Applied Mechanics and Materials Vols. 253-255

Abstract: The PAN-based carbon fiber (CF) was choosen as a bio-carrier in waste water treatment process, which was modified by anodic oxidation and electropolymerization using sulphuric acid and maleic anhydride (MA) respectively. The morphology and propeties of CF surface were characterized by laser confocal microsopy (LCM), X-ray photoelectron spectroscopy (XPS) and the degree of moisture (DM), and the consequence of biocompatibility nature on CF surface was therefore indicated by immobilization results of microorganisms. It shows that the surface hydrophilicity, oxygen containing groups and surface roughness of CF would contribute greatly to improve the immobilization ability of microorganisms on CF surface. And acid anodic oxidation is more effective on microorganism immobilization than MA electropolymerization.

Abstract: Integrated wetlands combined with emerged macrophytes and hydrophytes provided an innovative option for treating storm water. The study evaluated the removal effect of nitrogen (ammonia, nitrate, nitrite, total phosphorus) and phosphorus (total phosphorus) for storm water in riparian wetland. The 15 month monitoring campaign investigated that most of the effluent nutrients (except nitrite) concentrations were significantly less than inlet concentrations. The nitrogen removal fluctuated widely over time, and the removal rates were associated with the cultivation of biofilm and reeds. Furthermore, the study also demonstrated that the removal efficiencies of nitrogen and phosphorus were not closely related to the rainfall duration.

Abstract: When organic load of mixed liquid is up to a certain value, organic matter content is not the restrictive factor of phosphorus release any more. Optimum organic load for phosphorous anaerobic release in HA-A/A-MCO process is 0.141gCOD/gMLSS.d. Sufficient phosphorus release in anaerobic phase is the premise that high efficiency phosphorus absorption can be obtained in anaerobic phase. The maximum of releasable phosphorus sludge per unit weight (Pm/M) in HA-A/A-MCO process is 5.7mgP/gMLSS

Abstract: In accordance with an orthogonal experiment design, a series of ACs for methylene blue (MB) removal had been prepared in the presence of small amounts of KOH in raw material combined with delicate acid washing after carbonization and before steam activation. ACs were characterized, and their adsorption capacities for MB were determined as well. It was found that it was feasible to regulate and optimize pore structure in coal-based ACs by tuning preparation conditions concisely and properly, and the MB adsorption capacities were linearly correlated with their specific surface areas. Based on statistic analysis, it was revealed that among the four process variables studied for the sorbent prepared in this work, the activation temperature was found to be the most significant one for the MB adsorption capacity, the next ones were the activation time, the flow rate of water vapor and the amount of KOH, and an optimized preparation condition was figured out.

Abstract: The objective of this research is to reduce the chemical cost of demineralized water production process. The jar test is used to determine the optimum poly-aluminium chloride (PAC) dosage requirements. This paper investigates the effect of PAC dosage on the turbidity and the pH. Moreover, the mathematical models to predict the percentage of the turbidity and the pH removal are proposed and developed in this paper. According to the experimental results, the optimum PAC dosing not only reduces the cost of PAC, but also reduces the cost of Sodium Hydroxide (NaOH). Since the reduction of PAC causes the decrease in acidity in the raw water. Hence, the NaOH used to adjust the the pH of the raw water, has less dosage. The chemical cost of the demineralized water production process is reduced by 27.5%

Abstract: CFU combined process is the Coagulation - Flotation - Ultrafiltration combined process.For the car washing wastewater with litter oil, this article mainly studies its oil removing effect.It selects five groups of opposite experiments to carry on the oil removing examination about the oiliness car washing wastewater, and analyzes the floating time, the flotation column effluent position, the dosage of the composite coagulant (PAM + PAFC) and the hollow ultrafiltration membrane filtration rate in CFU combined process’s optimal operating condition, and also compares oil removing efficiency among various kinds of crafts when it adds the ultrafiltration membrane. The experimental results show that: for the small oil-content wastewater (in this experiment,the wastewater is car washing wastewater,the oil content is 5.28mg/L ~13.47 mg/L), the oil removing rate of CFU combined process can reach more than 40%,which nearly doubles the oil removing rate of the conventional coagulation - flotation process.

Abstract: In this paper, concentrations of six heavy metals (Cr, Mn, Cu, Zn, As, Pb, Fe) in soils from different function zones of Suzhou city were determined and analysed by X-Ray fluorescence spectrometer and fuzzy mathematics model. The results show that concentrations of all except Zn were within the national second class standard, but that of all heavy metal were higher in soil background values in Anhui province; concentrations of heavy metal were different in different function areas, and heavy metal pollution was more serious in commercial area, industrial area and near the station than in residential suburb, cultural and education districts; the contaminate level of every sampling site by fuzzy mathematics model was: 7>19>6>9>14>1>17>20>4>11> 23>8>22>3>10>12>5> 16>15>2>13>18>21.

Abstract: Using the numerical simulation method, this thesis studies the radon concentration distribution in downwind area of the flat ground uranium tailings impoundment with and without vegetation on the beach face under the wind speed of 0.5, 1.0, 2.0 and 4.0m/s. The numerical results show that the radon concentration decreases gradually with the increasing wind speed and distance from uranium tailings impoundment. As the wind speed is 0.5m/s, the radon concentration is higher in downwind area of uranium tailings impoundment, and accumulation range is larger and local pollution also becomes more serious. However, radon concentration and accumulation range falls rapidly with wind speed increased to 4.0m/s. At the same wind speed, radon concentration under the condition of beach face with vegetation is higher than the one without vegetation within 600m range of uranium tailings impoundment along the downwind direction, but radon concentration is lower under the condition of beach face with vegetation out of 600m range. It illustrates that vegetation can inhibit radon diffusion to some extent.

Abstract: Based on the discrete phase model (DPM), this paper studies the concentration distribution and settlement regularity of particles which sizes are 10μm and 100μm under the wind speed of 0.5, 1, 2, and 4m/s with the method of numerical simulation. The simulation results show that the particle concentration of 10μm at the downwind direction of tailing is constantly decreasing with the increase of wind speed and migration distance, and the particle concentration of 100μm is gradually increasing, as well as the local pollution also become gradually worse. As wind speed is 0.5m/s, the local concentration of 10μm particles at the beach face of uranium tailings impoundment is higher, and there is much deposition within 2000m of the downwind direction. While the dust emission rate of 100μm is less and its concentration is lower.10μm particles are taken away by the wind, and its concentration would fall rapidly with wind speed increased to 4.0m/s. The concentration of 100μm particle would increase and local pollution becomes more serious.

Abstract: The study shows that geological disasters caused by mining is different from the natural one, which has a lagging effect and the persistence, and causing some epigenetic disasters. Some long term effect phenomena are described in detail, their causes are discussed, and some prevention and cure measures are also posed out in this paper.