Advanced Materials Research Vols. 356-360

Abstract: In this paper, in considering the influence of interaction and material decomposition, the generation of NOx inside the rotary kiln and precalciner, which are the main NOx emission equipments in cement production process, are simulated by CFD technology, and the results is tally with the actual situation. This shows that numerical simulation can be a very good guidance on NOx emission reduction technology and staged-combustion precalciner structure design, and we can design and optimize the NOx emission reduction scheme based on numerical simulation to achieve the purpose of reducing NOx pollution in cement production.

Abstract: This paper was based on pore volume distribution function which can be measured by experimental apparatus, proposed two methods of establishing microstructure distribution model for the calcined product of Ca-based absorbent, got the distribution models of pore volume, specific surface and pore length for the absorbent, and carried out comparison studies for the pore size distribution characteristics which was got both by model simulation and experiment, then compared the two models to observe the applicability of them. The result has showed that these two models both can describe the pore size and its distribution of Ca-based absorbent completely, the equivalent aperture of the logarithmic model was as same as definition, it was more appropriate when the pore radius is relatively small, and when the pore radius was relatively large, exponential model was better.

Abstract: Conventional and modified membrane bioreactors (MBRs) are effective increasingly used in small sized wastewater treatment plant. However, their widespread applications are hindered by their elevated energy consumption and the high costs of investment for the membrane modules. In this study, we investigated a modified an improved MBR system that utilized a cost effective woven fabric instead of nonwoven as the filter material in MBR modules. The woven fabric bioreactor (WFBR) system was operated in a continuous mode at HRT from 33 to 12h. Under the operational conditions of BOD loading rates from 0.12 to 0.28 kg BOD/kg MLSS /d, the WFBR system was able to reduce up 93.57% COD. The 38μm woven fabric performed well in solid-liquid separator, with an average suspended solids retention of 99.47% at MLSS of 4710~9951 mg/L. The WFBR system eliminated suction pumping by using a gravity head in the membrane filtration of the effluent over the entire operational period of 60 d.

Abstract: Aiming at the necessary of the research about agricultural soil pollution, fully integrated real monitoring results of agricultural soil pollution, combined with the theory of fuzzy mathematical analysis and geographic information systems technology, the main purpose of the fuzzy comprehensive assessment system is to reveal the formation, dynamic changes of agricultural soil pollution and the movement of pollution, providing effective management decision for agricultural soil pollution prevention and planning management.

Abstract: Pharmaceutical wastewater was treated by micro-electrolysis and Fenton process.The aim of this research was to optimize operating parameters in micro-electrolysis and Fenton process. Effectiveness of important process parameters such as mass ratio of iron to carbon, the initial pH, reaction time and H₂O₂ dosage on the performance of micro-electrolysis and Fenton process were investigated. The results show that the removal efficiency of pharmaceutical wastewater chemical oxygen demand (COD) could reach 37.3% at the optimal pH of 4 with the iron to carbon ratio of 1:1 after 80 min treatment. The operating conditions of Fenton process are 0.5% of H₂O₂ dosage, the pH value of 4 and the reaction time of 180 min. The pharmaceutical wastewater COD removal could reach 79.4%.

Abstract: The effects of the coal char on reducing NO emission with and without additive were studied at high temperature in order to decrease the fuel-N discharge in the circulating fluidized bed boiler. According to the experimental results, combining the calculating models and boundary conditions, the NO content distribution with and without additive were separately calculated through the FLUENT6.3 in a 460t/h CFB.The results indicated that the coal char specific surface area and reaction rate constant were increased with the addition of additive; the calculating models was suited; The NO weight percent was decreased with the addition of TiO₂ additive in the CFB. The experiments and simulation results suggested a reference basis is provided for improving the removal effect of the feul-N in circulating fluidized bed boiler.

Abstract: With inoculum sludge from a conventional activated sludge wastewater treatment plant, formation of aerobic granular sludge for simultaneous phosphorus and nitrogen removal was realized in a sequencing batch reactor by the selective pressure as a driving force. Selective pressure created by means of decreasing sedimentation time and increasing substrate loading enhanced the formation of aerobic granular sludge, which followed four consecutive stages: acclimation, granulation, growth and maturation. Under the condition that the substrate loading were increased to 500mg COD/(L•d) and 48mg NH₄ ⁺-N/(L•d), the granules were the dominant sludge forms with most of diameter about 0.5–2.0 mm, a minimal settling velocity of 0.55 cm/s and a MLSS of 6800 mg/L after 120 days operation. The granules were composed of filamentous species with varying degrees of rod- and coccal-type bacteria. Microscopic examination revealed that granules microecosystem was more stable and should be less vulnerable to the changes of mixed liquor condition.

Abstract: FeC₂O₄ supported on resin as an effective catalyst for oxidation was prepared and applied for the degradation of azo dye C. I. Reactive Red 2BF（2BF），using hydrogen peroxide as the oxidant. When the initial concentration of Reactive Red 2BF was 200mg / L under solar light radiation for 70min, the removal of concentration and TOC of 2BF reached 90%% and 79.7%, respectively. FeC₂O₄-resin remained efficient after six repeated experiments.

Abstract: The effects of individual inorganic anions (nitrate and chloride) on the reactivity of granular iron were investigated using plexiglass columns packed with granular iron. The results show that TCE removal decreases apparently with increasing nitrate concentration due to competition for reactive sites. Chloride exhibits dual-effect on the TCE removal by Fe0. In the studied condition, the TCE dechlorination is enhanced at the low chloride concentration due to pitting corrosion and is dampened at the high chloride concentrations such as 59.98 and 110.45 mg/L as Cl-.

Abstract: The performance of nitrogen and phosphorus removal was investigated in pilot-scale A²/O, A²/O-MBR and mA²/O-MBR processes for treating municipal wastewater. The results show that these processes had a similar COD and ammonia removal efficiency, but A²/O process had better denitrification efficiency than MBR processes. In order to explain the difference of nitrogen and phosphorus removal performance in the investigated processes, specific oxygen uptake rate (SOUR), specific denitrification rate (SDNR), anaerobic release rate and anoxic and aerobic uptake rate of the activated sludge taken from A²/O and mA²/O-MBR processes were compared. The results show that the activated sludge of mA²/O-MBR process had a higher nitrifying activity in aerobic tank than A²/O process, the denitrifying activity in anoxic tanks were roughly equal and A2/O process had a higher denitrifying phosphorus removal activity in anoxic tank than mA²/O-MBR process.