Advanced Materials Research Vols. 610-613

Abstract: From October 2009 to September 2010, this study focused on investigation the performance of a subsurface wastewater infiltration (SWI) system in treating domestic sewage, and evaluated the potential of the surface water pollution by using the SWI system. The results showed the removal efficiencies were relatively high: for biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), ammonia nitrogen (NH₃-N) and total phosphorus (TP) were 95.0, 89.1, 98.1 87.6 and 98.4%, respectively. Meanwhile, the monitoring of a nearby stream characteristic indicated the SWI system could not decrease the receiving surface water quality.

Abstract: The volume of FGD wastewater of coal-fired power plant is very large, and it contains a large number of inorganic salts, suspended solids and heavy metals, the directly discharge of wastewater will cause a lot of pollution to the environment. This paper selects the FGD wastewater of Baoding power plant as a research object, it is taken experimental study by physical and chemical methods, the harmful substances in the wastewater are removed, so the quality of FGD wastewater achieves the national emission standards of sewage.

Abstract: The removal of perfluorooctanoate （PFOA） and turbidity from model solution by coagulation was investigated. A polyaluminum chloride (PACl) was used as a coagulant in the coagulation process. The effects of coagulant dose, slow mixing time, solution pH value and initial turbidity on the removal of both PFOA and turbidity from water were studied. It was found that the removal rate of PFOA in water increase along with the increase in slow mixing time, initial turbidity and PAC dose. The removal rate of PFOA is more effective at the near neutral solution pH values and the high initial turbidity. The removal percents of PFOA exceed 80% at the optimal condition. The removal mechanism was speculated to be the electrostatic interaction and hydrophobic interaction in coagulation process.

Abstract: The effect of different organic carbon sources on Cr(Ⅵ) reduction by Bacillus sp. was investigated. Three organic compounds, malate, succinate and glucose were tested in Cr(Ⅵ) reduction experiments. The results demonstrated that three organic compounds all significantly enhanced Cr(Ⅵ) reduction. The enhancing degree of these three organic compounds was observed as malate>glucose>succinate, although the cell growth in succinate-added medium was similar to that in malate-added medium and was apparently higher than that in glucose-added medium. Addition of glucose resulted in decrease of pH and increase of redox potential, while addition of malate or succinate resulted in increase of pH and decrease of redox potential during Cr(Ⅵ) reduction. Cr(Ⅵ) was reduced by liquid culture metabolite when glucose was added in liquid medium, but not reduced by liquid culture metabolite when malate or succinate was applied in liquid medium for bacterial cultivation.

Abstract: A study was performed of the atomization feature of liquid-column tower. It was found that the broken droplets can be classified into three types which called convex,twisted and broken. Proposed that the atomization process of liquid column tower consist of impact atomization and run into a wall atomization. Analysis of the atomization mechanism of the two processes, and the run into a wall atomization have droplet rebound,expand,splash stages. In addition ,the high degree of atomization of theoretical formula was amended. After modified, the theoretical and actual values are basically consistent.

Abstract: Researching on the feasibility of citrate wastewater recycling treatment, the combined treatment methods of coagulation and filtration were adopted in the recycling treatment process of citrate wastewater from secondary biological treatment effluents. Meanwhile the ferric salt and water treatment processor were used as the coagulant and filtration equipment respectively. The experiments of coagulant addition, hydraulic retention time, the volume ratio of compounded filtering materials, aeration intensity were taken respectively. The final experimental results demonstrated that at the ferric salt addition of 36 mg/L, hydraulic retention time of 40 min, the volume ratio of biological fibred ball / biological carbon and the ratio of water/gas were 1:2 and 1:6 respectively, 81.3% of COD was removed, from179.2mg/L down to33.6 mg/L and 96.7% of SS was removed, from 152.7mg/L down to below 5mg/L. The effluent of the citrate wastewater recycling treatment process with coagulation + water treatment processor could meet the National standard of Recycling and Miscellaneous usages of Municipal Sewage on COD and SS requirements.

Abstract: Phenol degradation with a UV/Ag+/K2S2O8 advanced oxidation process (AOP) was studied in a batch photolytic reactor. The UV irradiation source was a low-pressure mercury vapor lamp that was axially centered and was immersed in the phenol solution. In the UV/ K2S2O8 and Ag+/K2S2O8 system, the degradation of phenol was inefficient with an low concentration K2S2O8 at ambient temperature, and only around 26% and 23%of the phenol was degraded in 3 h , respectively. In the UV/Ag+/K2S2O8 oxidation process, persulfate (S2O82-) was activated by UV irradiation and Ag+ catalysis to produce powerful oxidants, SO4– •.The effects of K2S2O8 concentration, UV irradiation time and Ag+ concentration on the oxidation had been investigated. The experimental results indicated that optimum K2S2O8 concentration was 0.37mmol/L, and Ag+ concentration was 0.185 mmol/L. Phenol and chemical oxygen demand (COD) reduction was analyzed to determine the efficiency of the UV/Ag+/K2S2O8 process in mineralization, where we obtained 77% phenol reduction, and 65% COD reduction, respectively . The efficient mineralization of phenol is based on the in situ formation of the strong oxidant sulfate anion radical.

Abstract: A pilot-scale nitrogen removal system composed of an anoxic area, an anaerobic area, a microaerobic area and an aerobic area (A₂O₂) was established to treat high strength ammonium wastewater from a nitrogenous fertilizer factory. The influences of key factors such as DO, pH, FA and temperature on partial nitrification in the microaerobic area were investigated. The results showed that in the DO concentration of 0.5~0.7mg/L, the stable and efficient nitrite accumulation could be realized. Meanwhile, the effluent NH₃-N and TN quality was superior to the requirement of the《Synthetic ammonia industrial water contamination emission standard》(draft for comment). The optimal pH of 7.5~8.0 and the corresponding free ammonia (FA) concentration of around 0.95 mg/L limited the nitrobacteria activity selectively, thus favoring the stability of partial nitrification. The nitrite accumulation rate didn’t show obvious difference in wide temperature range (18~35°C) at given DO (0.5~0.7mg/L) and pH (7.5~8.0). But contrary to the usual partial nitrification obtained by high temperatures (>30°C), the effluent ammonium of A₂O₂ system was substandard due to the inhibition of nitrobacteria activity caused by high temperature, which diminished the further removal of ammonium in the subsequent aerobic area.

Abstract: As a high concentration organic wastewater, papermaking wastewater is so strong stability that it is difficult to be decomposition by microorganisms [1, 2]. Through adding aluminum sulfate Al₂（SO₄）₃, the stability of the wastewater will be changed and the value of the COD _Cr will be lower. The effect of some important operation parameters, such as the dosage of the pharmaceuticals, pH value and stirring intensity were investigated and optimized. After the experimental, the results showed that, when the optimal dosage of Al₂（SO₄）₃ was 1.5g/L, the solution pH controlled in 6~8, it could get the best treatment effect.

Abstract: After selecting 25 samples from pond sediments in Sixian County, northern Anhui Province, China, this article analyzed the Zn content in pond sediments with X-RF fluorescence spectrometer analysis and carried on the ecological risk evaluation. The results indicate that the concentrations of pond sediments range from 20 to 34 mg/kg with average= 26.7 mg/kg, The lead concentration from high to low is Wuwei, Xinji, Huangwei, Dazhuang, Yangzhuang, central zone. By pollution index evaluation methods and enrichment factors methods, the result of Zn content in pond sediments showed that the Zn content was slight pollution.