Applied Mechanics and Materials Vols. 178-181

Abstract: For heavy oil wastewater from Henan oilfield, removal of silica has been investigated under the condition of different flocculants and reaction time when magnesia has been used as a desilica agent. An optimum method has been determined by conditional experiments, 63% of silica could be removed.

Abstract: This experiment used tetrabutyl titanate, hydrochloric acid as the main precursors and had prepared nano TiO₂ particles by the sol-gal process. And the prepared TiO₂ nano-powder were characterized using X-Ray Diffraction (XRD) and other methods. In order to have qualitative phase analysis of the prepared samples, the article took the photo-catalytic degradation of rhodamine B solution as the model reaction and inspected the photo-catalytic activity of the prepared nano TiO₂ particles. The experiment data and results showed the prepared TiO₂ samples were anatase TiO₂ and they had very good photo-catalytic activity on the water samplings.

Abstract: Through the research of close type separation device sedimentation tank (CTSDST) in static water test, it can be seen that change of effluent turbidity with time includes the two stages that turbidity diminishes quickly stage and turbidity decreases slowly stage in the static water precipitation. Meanwhile the results show that the sediment concentration of muddy water has little effect on the change of effluent turbidity with time and the effect of water purification is better than the sedimentation tank of no separation device. Moreover the CTSDST has many features such as energy saving, stable discharging water, small footprint, easy operation and maintenance, etc.

Abstract: Bi-functional mesoporsous silica adsorbents, functionalized via the introduction of chelating agents (mercaptopropyl and aminopropyl groups) were prepared to adsorb Co²⁺ and Mn²⁺ in dilute solutions. The molar ratio of MPTMS/APTMS in grafting process seemed to have great effected on the mesostructure of adsorbents, and the appropriate value was considered to be 2/1. The modified silica gels at that ratio showed well-ordered property as well as its high infinity of the two metal ions. The pseudo-second-order equation was applied to describe the adsorption kinetics. And the influence of interferential ions Ca²⁺ and Mg²⁺ was also studied.

Abstract: Based on recent experimental data in the Guangrao Wastewater Treatment Plant, the performance and dynamics of modified A² / O process was summarized. The results shows that: the average removal rate of COD is 73.7%, and COD is mainly removed in pre-anoxic pool; the average removal rate of TN is 64.2%, and TN is mainly removed in pre-anoxic and aerobic pool; the average removal rate of TP is 79.48%, and phosphorus release happens in the pre-anoxic pool and phosphorus uptake happens in anoxic and aerobic pools. Based on the material balance and the results, the dynamic equation of degradation for pollutants in each stage is established, and the predicted and actual values are compared, the results show that the dynamic equations are fit for the Guangrao Wastewater Treatment Plant.

Abstract: In the wastewater treatment process, it is necessary to detect the concentrations of organic matter in order to monitor the operation and adjust the process parameters. Based on fluorescence excitation-emission matrix spectrometry, Chemical oxygen demand (COD) of effluent wastewater in the primary sedimentation tank, the secondary sedimentation tank and the final sedimentation tank of Hengdian Wastewater Treatment Plant, Zhejiang Province, is detected respectively based on fluorescence excitation-emission matrix spectrometry. In order to compare the modeling performance, principal component regression (PCR), partial least squares (PLS), parallel factor analysis (PARAFAC) and multi-way partial least squares (N-PLS) are respectively used to build the calibration models between the fluorescence spectrometry and COD. Experimental results show PLS is better than PARAFAC and N-PLS in the aspect of modeling performance for detecting COD in the wastewater.

Abstract: China has to confront the groundwater resources crisis and the deterioration of groundwater environment. Reinforcing the studies on groundwater pollution source identification (GPSI) could be an important support to contamination removing, groundwater protecting, drinking water security, and development of society and economy. Exploring the new theory and method on GPSI could push the studies on ill-posed problems, and improve the techniques of contamination remediation. GPSI has been studied for thirty years, and a brief review is given to conclude the characteristics of GPSI problems. The mathematical simulation method can be classified into four types: optimization method, analytical and regression method, direct method, and stochastic method. A specific review of optimization approaches is given in this paper. The configuration, simulation procedures, common optimization algorithms used by the optimization methods are discussed in detail. Both non-heuristic and heuristic algorithm can be used to solve the PSI problem. The heuristic algorithm is more suitable for complex numerical and field cases, but it is time-consuming. The non-heuristic algorithm, especially the algorithm combined with analytical method, is time-economical, but is not suitable for complicated numerical and field tests. Further researches may focus on more complex GPSI problems, expressing physical chemistry and biological process, improving efficiency and model uncertainty of GPSI modeling.

Abstract: In this paper, we followed the kinetics of methyl methacrylate (MMA) through a novel fluorescence method. The real-time measurement results show that in the regime of very low monomer contents, such as a solution containing 0.1 wt% of MMA with respect to water and with the anionic surfactant of sodium dodecyl sulphate (SDS), the kinetic of the miniemulsion could be followed by this embed fluorescence method. The processes of changing from emulsion to miniemulsion with different amount of surfactant and cosurfactant also have been monitored.

Abstract: A new composite coagulant, polymeric ferric aluminum chloride-polydimethyl diallylammonium chloride (PFAC-PD), was prepared by combing Polymeric ferric aluminum chloride (PFAC) with polydimethyl diallylammonium chloride (PDMDAAC). The turbidity, ultraviolet absorbance at 254 nm (UV254) and specific ultraviolet absorbance (SUVA) removal and flocculating mechanisms of the new composite coagulant and the traditional coagulants (PFAC, adding PFAC before adding PDMDAAC and adding PFAC after adding PDMDAAC) were investigated in treating surface water. The results indicated that the new composite coagulants exhibited better flocculation efficiency than PFAC and successive addition of PFAC and PDMDAAC. The neutralization ability of the coagulants was in the following order: PFAC-PD > PD+PFAC > PFAC+PD > PFAC.

Abstract: Choose to use different size a coleus blumei，with natural palm tree hair fiber for suspend to carry a body and regulate to go together with heavy to constitute to certainly plant system, observe a coleus blumei the growth condition in water body and improvement fluid matter effect in eutrophic waters. The results showed that coleus blumei completely can give birth very well in water suspend growth；that every coleus blumei could bring about many fibrous roots which reached 0.10cm to 0.15cm in the first day and that the longest fibrous roots reached about 16.5cm to 24.0cm during 15 days. The biomass measurement discovers that the plant more big its biomass increase more big，the plant is more small it the clean increment biomass be more big.The water body clarity raises to from the 41cm to 97cm and compare to change into almost transparent clear water for the muddy lake water；and the concentrations of CODCr,TP and TN were decreases to 80.0%，88.6% and 93.8% respectively.The DO concentrations also kept in certain satisfied level for using the coleus blumei method.