Applied Mechanics and Materials Vols. 209-211

Abstract: In order to screen the microalgae species for purifying aquaculture wastewater effectively and producing biomass with high nutritional value, two species of microalgae lately isolated from aquaculture wastewater were studied concerning theirs growth, removal efficiencies of nitrogen and phosphorus, and nutritional property. Results showed that the maximum biomass (dry weight) of Scenedesmus and Selenastrum were 0.78g•L-1 and 0.53g•L-1, respectively; their maximum biomass (dry weight) growth rate were 0.05g•(L•d)-1 and 0.03g•(L•d)-1, respectively. In 23 days, the removal efficiencies of TN by Scenedesmus and Selenastrum were 85.1% and 72.5%, respectively; TP could be efficiently removed by 82.6% and 79.7%, respectively. At the stable phase, the crude protein content and crude protein production (dry weight) of Scenedesmus, Selenastrum were 31.8%, 19.2% and 0.24g•L-1, 0.09g•L-1, respectively; the crude lipid content and crude lipid production (dry weight) of them were 7.81%, 9.26% and 0.06g•L-1, 0.05g•L-1, respectively. In general, Scenedesmus has obvious advantages over Selenastrum in the respects of growth, removal of nitrogen and phosphorus and nutritional value, and it can be used as the preferred algal species for follow-up study.

Abstract: In this experiment, cyclodextrin cross-linked magnetic chitosan（CCMC ）microsphere was prepared, glutaraldehyde was chosen as crosslinker, Cyclodextrin and chitosan was synthezied. To observe the influence factors of adsorption and obtain the optimum condition, the adsorption of copper ions by CCMC was explored under the different pH, initial concentration, temperature, reaction time and so on. The results indicated that CCMC had a high percentage removal of Cu2+, optimum adsorption was observed at pH 5.0. The adsorption rate of Cu2+ on CCMC was quick and the percentage removal reached beyond 90% after 30min, indicating that the adsorption equilibrium could be established within 30 min. The kinetic and thermodynamic properties of CCMC was also explored, under the concentration of Cu2+ of 50mg/L, 100mg/L, 150mg/L, 200mg/L, 300mg/L, 500mg/L on the temperature of 25°C, 35°C, 45°C, 50°C. Freunlich isothermal to Langmuir isothermal was used to fit the data of adsorption capacity of Cu2+, which showed that the adsorption process of Cu2+ was better described by Freunlich isothermal than Langmuir isothermal. As to the kinetic properties, the experimental data of Cu2+ adsorption onto CCMC fitted to the pseudo-first order model and pseudo-second order model, but the adsorption of Cu2+ onto CCMC conformed to pseudo-second order model, the R2 reached above 0.999.

Abstract: The scheme selection and system design of the regional central air conditioning system of Xiezhuang Coal Mine were presented. The cascade utilization of Mine water and recycled water of electric power plant was realized in this system. The system works well with decent economic benefits and accord with energy conservation and pollution reduction. At the same time, the economical efficiency and emission reductions of this system were analyzed, providing reference for regional central air conditioning system of the same type. The modulus of this system reaches comprehensive energy efficiency coefficient 4.83 in summer and 23.41 in winter. The increasing income and the saving investment are about RMB1.87b/a. CO₂ emission reduction is 249.4t/a, SO₂ 11.3t/a, smoke and dust 8.5t/a, ash 147.4t/a.

Abstract: The water qualityr was considered by multiple regression analysis. The linear relationship between integrated pollution index and weight pollution index were obtained, the 5 day biochemical oxygen demanded and total nitrogen were the most important pollution factor by the relationship. And then, the two main components influencing water quality were given based on the principal component analysis affecting data..

Abstract: Comparing and analyzing the traditional electrocoagulation device and the special cyclic electrocoagulation device in this experiment, based on that, screening the factors that might influence the effects of coking wastewater, adopting the intermittent test method and analyzing the orthogonal design table, as a result, the factors that have better values respectively: plate spacing 3mm, reaction time 8min, current strength 11.5A.

Abstract: Concentrations of six types of metals (including Cr, Co, Ni, Cu, Zn and Pb) in twelve groundwater samples from two different aquifers (coal bearing and limestone aquifers) in Renlou coal mine in northern Anhui Province, China have been analyzed by using ICP-MS and processed by statistical analysis for tracing their sources. The results indicate that the concentrations of metals are as follows: Cu(6.68 mg/L)> Cr(2.39 mg/L)> Ni(1.03 mg/L)> Zn(0.882 mg/L)> Co(0.569 mg/L)> Pb(0.116 mg/L). Concentrations of Cr, Ni, Cu and Pb are several times (47.8, 51.5, 3.3 and 8.0, respectively) higher than the drinking water standard of WHO, and indicating that these groundwater cannot be used for drinking directly. Two components (eigenvalues higher than one) have been obtained by using factor analysis with a total variance explanation of 88.7%, and two sources for metals in the groundwater have been identified that Cr-Cu and Co-Ni-Pb are originated from different sources. Moreover, the differences of metal concentrations between groundwater in these two aquifers suggest that they can be used for water source discrimination.

Abstract: Abstract. The saturated SiC with the adsorption of Mn2+ was regenerated dynamically by water backwashing and NaOH, and the Mn2+ removing effect was compared by the two ways .The results showed that on the condition of Mn2+ concentration at 1.7～2.2 mg/L ,flowing speed at 7.8 m/h, the regeneration rate of saturated SiC was only 49.8% after the first regenerated by backwashing .As for the second time ,the rate was less than 15%,which had lost Mn2+ removing ability .But by NaOH, the regeneration rate was more than 100% after the fifth regenerated ,which was obviously better than that of backwashing .And further study was conducted on Mn2+ removing mechanism by SiC through SEM figures.

Abstract: Removal of iron in groundwater using biological filtration column are researched. Natural organics with different molecular mass can be removed using molecule filtration membrane. Test results showed that the molecular mass of organic influenced effluent quality. The greater is organic molecular mass, the lower the removal rate of iron, DOC and UV254. Removal rate of DOC and UV254 in groundwater with organic of molecular mass less than 1000 were 82.4% and 65.8%，respectively，but Removal rate of DOC and UV254 in groundwater with organic of molecular mass more than 30000 were 28.5% and 54.3% respectively.

Abstract: Being frequent in recent years, "gutter oil" problem attaches great importance to the society. The most effective way to eliminate “gutter oil” is to put it into the recycling system through scientific planning so as to play its due role. To this end, an effective swill recycling device is proposed, which is able to turn waste into treasure and save energy. The device makes swill pretreatment, and separate it in transit. Owing to the high-efficiency pretreatment, this device not only increases the recycling output, but also relieves the loads of factories which produce biodiesel.

Abstract: A modified peat was prepared by using nitrate and natural peat from Yiyang city in Hunan Province. The adsorption properties of the nitrifying peat for Methylene blue was investigated in aqueous solution. The effect of the adsorbent dosage, time and the initial concentration of methylene blue on the adsorption capability was discussed. The result showed that time and the adsorbent dosage had greater influence on the adsorption of Methylene blue, the adsorption of Methylene blue by Nitrifying peat was a rapid process, and in 20 min in the adsorption rate reached more and 60%, the adsorption amount was approximately proportional to the initial concentration( 20-100 mg /L). Langmuir and Freundlich isotherms were used to fit the equilibrium data, and it was found that the adsorption isotherm followed the Langmuir model.