Advanced Materials Research Vols. 518-523

Abstract: Tribromoacetic acid (TBAA), one of the typically recalcitrant and toxic chlorine disinfection byproducts (DBPs), is widespread in the drinking water and threating human health. The environment-friendly technology, UV irradiation, could efficiently destruct TBAA. The present study investigated the removal efficiency, photodegradation kinetics, and photodegradation mechanism of TBAA under UV irradiation. It revealed that the photodegradaton process of TBAA agreed well with the pseudo-first order kinetics, with the rate constant of 1.084 min^-1 and half-time of 0.64 minutes. Further study on intermediate products formation and mass balance indicated that complete debromination and detoxification were obtained with almost all the bromine atoms released as bromide ions, and suggest that the cleavage of three C-Br bonds concurrently occurred during the photolysis of one TBAA molecule. It will provide some guidance for efficient treatment of brominated contaminants in water.

Abstract: The 45-days’ laboratory start-up study examined the performance of a novel horizontal flow biofilm reactor (HFBR) system in the treatment of a synthetic domestic-strength wastewater. In this study, the sheets were alternately offset to make sure the wastewater flowed horizontally along each sheet and vertically shifted down through the reactor. Biofilms developed on the sheets and purified the wastewater. In order to obtain the HRT while the flow rate changed, we calculated the ratiocination between the flow rate and the system HRT. The system was easy to construct and start, did not clog and could be used for biodegradable COD removal.

Abstract: A field pilot test was constructed on a two stage Dissolved Air Floatation (DAF) combined with Activated Sludge Process (ASP) and Immobilized microorganism biological filter (I-BF) has been constructed in Liaohe oilfield, China to treat heavy oil wastewater with large amounts of dissolved recalcitrant organic compounds and low nutrient of nitrogen and phosphorus. By operating the system for 185 days, chemical oxygen demand (COD) removal rates were 67.9 % and 88.4 % in DAF and I-BF effluents, respectively. Environment Scanning electron microscope (ESEM) showed that large quantity of filamentous microorganisms was immobilized on carriers without causing foaming or bulking. This integrated system appeared to be a useful option for the treatment of heavy oil wastewater in Liaohe oil field.

Abstract: The static adsorption of stainless steel pickling wastewater by ion resin exchange and activated carbon adsorption was studied respectively. The results shown that, the static saturate adsorption capacity of 001×7 dry resin for Cr3+and Fe3+ in the wastewater was 60.34mg/g and 65.3mg/g respectively, and the elution rate of saturated resin by using Na2SO4 and H2SO4 can reach 99%. The saturate adsorption capacity of activated carbon for Cr3+and Fe3+ in the wastewater was 4.55 mg/g and 40.76 mg/g respectively, and NaOH as desorption reagent had a good desorption effect to activated carbon. The regeneration of activated carbon was also carried out.

Abstract: Organic polymer carrier was utilized to treat textile wastewater. Results showed that COD removal efficiency was almost 82.8%. The average effluent COD concentration was 132.6 mg/L. The effluent colority was about 200 times. Experiment indicated that ceramic granular carrier was better than polymer carrier when ultlized to treat textil wastewater.

Abstract: A new heteropoly salt with Keggin structure of the 1:1:11 series had been synthesized, and characterized the structure by the foruier transform infrared spectroscopy (IR), ultraviolet spectra (UV) and X-ray diffraction (XRD).The thermal stability and the number of the crystal water was analyzed by the thermal gravimetric analysis/differential thermal analysis (TG/DTA). It was showed the molecular formula was Na₅[Ce(ZrMo₁₁O₃₉)]•16H₂O( Abbrev.CeZrMo),it possessed Keggin structure and had good thermal stability. The influences on the degradation rate, such as the amount of the CeZrMo, the initial concentration of the AGB dye wastewater, the ultrasonic frequency and power, were investigated. The results showed that the degradation rate could reach 88.01% after 60min irradiation, when the amount of the CeZrMo was 0.8g•L^-1, the concentration of the AGB was 10mg•L^-1, the ultrasonic frequency was 45kHz and the ultrasonic power was 100W.

Abstract: Forecasting air quality time series represents a very difficult task since air quality contains autoregressive, linear and nonlinear patterns. Autoregressive Integrated Moving Average (ARIMA) models have been widely used in air quality time series forecasting. However, they fail to detect extreme events because of their presumed linear form of data. Artificial Neural Networks (ANN) models have proved to be promising nonlinear tools for air quality forecasting. A hybrid model combining ARIMA and ANN improved forecasting more than either of the models used independently. Experimental results with meteorological and Particulate Matter data indicated that the combined model can be used as an efficient forecasting and early warning system for providing air quality information towards the citizen, not only in Sfax Southern Suburbs but in other Tunisian regions that suffer from poor air quality conditions.

Abstract: The volume ratio of anaerobic/anoxic/aerobic was an important factor for the removal of nitrogen and phosphorus in the A²/O process. A pilot plant of A²/O process was built in Xi’an to do the research about the influence on nitrogen and phosphorus removal when the volume ratio of anaerobic/anoxic/aerobic was changed. When the HRT was 10.1h and the volume rate of anaerobic/anoxic/aerobic was 1/1.7/2.4, the removal rate of COD didn’t raise substantially than that of normal volume ratio A²/O process, the removal rate average value of TN and phosphorus were 61.5% and 85.4% respectively. On this condition, the HRT in aerobic zone shorted to 4.7h, energy was saved about 33.8% in comparing with that of conventional volume ratio A²/O process.

Abstract: The treatment of corn processing wastewater by membrane bioreactor was studied in this paper. The results showed that COD_Cr and NH₃-N were eliminated efficiently by single-stage aeration MBR. The average concentrations of COD_Cr and NH₃-N in the effluent were 53.1 and 1.29 mg/L, and the removal efficiency were 92.9% and 93.0_{Subscript text}% respectively. But the removal efficiencies of TN and TP were limited, as 46.7% of TN and 41.6% of TP were removed. The subsequent processes (coagulation,reverse osmosis,etc.) may be needed to achieve the goal of water reuse.

Abstract: The dewatering of municipal sewage sludge is a current problem due to the huge production of this waste. The bound water content in sludge is closely related to the sludge dewatering performance. By comparative analysis of the measurement methods of the bound water content in sludge, this article points out their respective advantages and disadvantages, as well as the respects which should be noted in practice.