Advanced Materials Research Vols. 610-613

Abstract: On account of severe water pollution condition, this paper combines structure emissions reduction, engineering emissions reduction and management emissions reduction (namely SEM emissions reduction), builds an optimization model for total amount control of regional water pollution, and puts the above model into practice to validate its validity and reliability. According to the case study, the emission reduction of COD and NH₃-N are 43.94 and 7.09 (10⁴ tons), respectively. The optimal total costs of reduction is 36.89 (billion yuan), which decreases 7.47% than the existed recommended scheme (39.87 billion yuan). This method can be used for providing technical support and thus achieves the 12^th Five-year goals of the environment protection plan more effectively.

Abstract: The smaller ceramsite particles were selected to be filled in a biological aerated filter (BAF) to remove ammonia nitrogen from the synthetic wastewater which did not contained COD. The effect of the filter layer, the inner reflux ratio and the ceramsite particle on the removal rate of ammonia nitrogen in the wastewater was investigated in the present study. The results indicated that the steady removal rate of eighty-eight percent was excitingly detected after the 24 days of the biofilm formation, and both the low and middle filter layer showed the removal rate of the wastewater ammonia nitrogen higher than the top layer. In addition, in the present study, the best inner reflux ratio of the present smaller-ceramsite BAF could be steadily kept in case of the slight fluctuation of the ceramsite size and the organic concentration of the wastewater.

Abstract: The recombinant plasmid pETac-CATHis with tac promoter was constructed for the constitutive expression of a thermophilic catalase in E.coli. And the effects of cultivation conditions of two recombinant strains, BL21(DE3)/pETac-CATHis and BL21(DE3)pLysS/pETac-CATHis, such as initial pH, cultivation temperature, cultivation time, and loading volume on catalase activity were investigated. The optimal cultivation conditions were: the initial pH 7.0, cultivation temperature 37°C, cultivation time 12 hours, and loading volume 25mL in 100mL flask. Under the optimal cultivation condition, the highest catalase activities of the two recombinant strains were 291.7 U/mL and 349.5 U/mL, respectively. After adding catalase, H₂O₂ in simulation H₂O₂ wastewater containing phenol was decomposed completely very quickly. Declining of catalase activity was detected with enhancing the phenol concentration, probably because the phenol might be a kind of competitive inhibitor for catalase.

Abstract: Using the hydrated calcium silicate slag which was the remain of preparation potassium sulfate, aluminum hydroxide and layered sodium silicate by thermal decomposition insoluble potassium feldspar as crystal seed to recover phosphorus in polluted water. By orthorhombic experiment of the adsorption, we can get the optimize condition: pH value is 5.3, slag concentration is 5g L^-1, the temperature is 35°C, the oscillation time is 8h. Equilibrium isotherms have been determined and analyzed by BET type. The pseudo second-order kinetics equation can be a better fit on adsorption phosphorus process.

Abstract: In order to improve the efficiency of CFB-FGD (circulated fluidized bed for flue gas desulfurization) in many thermal power plants, this paper used the improved genetic algorithms and BP neural network to model and optimize the operation of CFB-FGD. First, this paper build BP neural network model to simulate CFB-FGD. Then, based on this model, we used the improved genetic algorithms to optimize CFB-FGD. The results can help improve the efficiency of CFB-FGD and decrease enterprise operating costs.

Abstract: In this study, the reed pulping medium wastewater was treated by the membrane bioreactor. The purpose of the study is to determine the operating conditions to the operation of internal membrane bioreactor for the treatment of reed pulping medium wastewater. The volume of the bioreactor is 15 litre in which develops an adapted biomass. The reed pulping medium wastewater was pumped from an influent trough into the bioreactor and a level sensor and a submerged pump were installed to adjust the water volume in the bioreactor. In the bioreactor the effluent separated from the activated sludge by the hollow fiber membrane module. The experimental have shown that the average rate of elimination of the COD is of 91.3%.The removal ratio of the Color reach 87.5%. The rate of elimination of the TSS is 90.2%.

Abstract: According to the performance test carried out in the SCR flue gas denitration system in 660 MW unit in a thermal power plant, several issues about the SCR flue gas denitration equipment were discussed, such as difficulty to accurately reflect the state of reliability, NOx emitting concentration overrun, export concentration uneven distribution and so on. Some suggestions were brought forward on how to deal with the issues.

Abstract: Degradation of Reactive Black 5 in aqueous solution was studied by double-dielectric barrier discharge, degradation efficiency and degradation mechanism has been investigated. Results shows that during in ten minutes degradation, decolorization efficiency can reach 98.76%,COD and TOC could not be reduce observably, while the biodegradability has been greatly improved, the BOD5/COD ratio increase from 0.079 to 0.495.Decolorization efficiency is higher than that of mineralization, decolorization follows the first order kinetics with a constant rate of 0.4008 min^-1. pH of the solution decrease gradually, but the conductivity increase during the degradation process. The ions of sulfate, nitrate, acetic acid, and oxalic acid have been found in the final treated sample and their concentrations increase with the reaction time. Chromophore group is damaged firstly and the solution has been decolorized efficiently, the degradation of benzene ring and naphthalene ring is more difficult than that of the azo bond, and the reduction or disappearance of absorption peaks indicates that the aromatic ring of KN-B was degraded partly.

Abstract: CdS/ZnS/TiO₂ composite photocatalyst was prepared by sol-gel and immersion method. The optimum preparation conditions were as follows: the mole ratio of XS (CdS, ZnS) and TiO₂ was 1:100; the mole ratio of CdS and ZnS was 1:1; calcined temperature 500°C; calcined time 1h. The optimum photocatalytic reaction conditions were as follows: the concentration of methyl orange 20mg/L, pH 5-7 and the catalyst dosage 2g/L. The removal rates of color and TOC were 84.3% and 54.2% using CdS/ZnS/TiO₂ under the Visible light irradiation, respectively.

Abstract: Zero-valent iron (Fe0) as one kind of redox material has widely been used to remove heavy metals from aqueous environments due to its low cost, simplicity and reliability. In this paper, interaction of Cr(VI) with Cu(II) in Fe0-H2O systems was studied in order to understand better the performance of Fe0 in wastewater containing multiple heavy metals. Results showed that Cr(VI) had inhibitory impact on Cu(II) removal by Fe0, resulting from competition of electrons generated from Fe0, while Cu(II) obviously enhanced the removal of Cr(VI), which could result from redox of Cr(VI) with Fe2+ from reaction of Fe0 with Cu(II) and then formed weak acid environments which were favorable for the removal of Cr(VI).