Advanced Materials Research Vols. 113-116

Abstract: Environmentally significant activity of alkaline phosphatase (APA), phosphorus loading and its species were determined in 14 sediment samples from Lake Hongfeng, one of the key drinking-water sources in Guizhou Province, China. The results of this research indicates that APA presented a high level and notable fluctuations with spatial variations in sediments, ranging from 8.712×10-5 to 25.667×10-5 mol of p-nitrophenol g−1•h-1, and the average value of total phosphorus (TP) in sediments from the lake was 1129.81 mg/kg (dry weight). The content of inorganic phosphorus (IP) was higher than that of organic phosphorus (OP), and the content of the iron/aluminum-bound phosphorus (Fe/Al-P) with phosphorus release risk was also high. In addition, the Pearson’s correlation analysis shows various correlations between APA and Ca-P, Fe/Al-P, OP and IP.

Abstract: The SPI was applied in food industry widely, but the functionalities of it may change during storage. The effect of store temperature, time, RH and package material on SPI component and oil absorption were studied, when SPI was packaged in 100% N2 and Al, 80%N2:20%CO2 and Al, 60%N2:40% CO2 and Al, vacuum and Al, white paper/plastic/HDPE, and PE and then stored for 5 months in the conditions of RH 80% and 30°C.It was shown that the 7S/11S of SPI only packaged in PE decreased significantly(p<0.05), while the subunit of SPI would lost in different levels and obviously in PE. It was observed by SDS-PAGE that the subunit of SPI disaggregated and molecules aggregated. Focus on the sulfhydryln group and disulfide bond, it was found that the content of sulfydryl decreases while disulfide bond increased.

Abstract: This paper reports a study on distribution characteristics of phosphorus and its species in 20 sediments samples from Lakes Baihua and Aha, based on the technique of sequential extraction. Baihua and Aha, two man-made reservoirs, are key drinking-water sources. The results, compatible with local geophysical characteristics, indicate that in sediments from both lakes, the concentrations of inorganic phosphorus (IP) were higher than those of organic phosphorus (OP), and the IP consisted mainly of calcium-bound phosphorus (Ca-P), which may temporarily control phosphorus release. Moreover, the concentrations of total phosphorus (TP) in both lakes sediments were high, thus phosphorus release potential and bioavailability were highly significant. Further statistical analyses revealed significant correlations with two extractable principal components allowing interpretation of possible origins of phosphorus loadings. Furthermore, available remediation measures were briefly evaluated for both lakes in consideration of their distinctive environmental features.

Abstract: A slag-based composite modifier(SBCM) was proposed for more effective sludge drying and solidification. The optimum composition of SBCM was determined by Uniform design and corresponding mathematical modeling. Sludge drying experiments were performed and the effectiveness of sludge solidification was examined using Chinese leaching toxicity test. The experimental results showed that optimized-SBCM behaved better than quicklime in sludge semi-drying and the leaching concentrations of heavy metal of SBCM-solidified products were lower than the sudge-quicklime mixture. Besides, microscopic analyses using XRD revealed that the main hydrated product of solidification was ettringite, which played an important role in the effective setting process and immobilizing most heavy metals of sludge. Sewage sludge solidified using SBCM could be used as an effective landfill cover.

Abstract: An anaerobic attached-growth bioreactor was set up to treat wastewater rich in sulfate and organic carbon. It was the pretreatment of mixotrophic desulfurization-denitrification process. With pH decreasing from 8 to 7, the sulfate removal rate and oxidation reduction potential increased, while sulfide generating rate and effluent pH decreased. When pH value was maintained at 7.5, the removal rates of sulfate and organic carbon reached 91.5% and 90.5%, respectively. Meantime, the generating rate of sulfide reached 47.8%, which was beneficial to the subsequent treatment and to the thorough removal of sulfurous compounds. The results showed that the suitable influent pH in sulfate reduction stage for the pretreatment of desulfurization-denitrification process was 7.5.

Abstract: The paper tries to expound environmental damage by fires and fire operations and thus draw more attention on environmental protection in fire protection. The environmental impacts are illustrated with many examples and concrete data. The article comes to the conclusion that: Fires result in not only casualties and economic loss but also permanent and unforeseeable environmental damage; People should try to enhance fire safety and cut down fire accidents while fire brigades should keep environmental protection in mind while fighting fires and choose environmentally friendly methods.

Abstract: La-Y-Ce-W cathode was prepared by powder metallurgy. XRD, OM, SEM and EDS were applied to analyze the microstructure of the material. La, Ce and Y concentrate on the tungstate particles and exist as Rare Earth (RE) tungstate. The average diameter of the particles is about 30µm. The electron emission properties were measured with self-designed electron emitter surveyor. Its effective work function was 2.76eV at 1300°C. The precipitation efficiency of an electrostatic precipitator (ESP) installed with the cathode was investigated in a certain flue gas condition. It was found that it can trap over 95% dust particles with diameter bigger than 1µm. As to dust particles with diameter smaller than 0.1µm, the efficiency is lower than 85%. Increasing collection voltages showed greater positive effects on the precipitation efficiency of smaller particles than that of larger particles.

Abstract: Because lack of water resources in Manas river basin, the water resources carrying capacity evaluation is important to the water sustainable development. In this paper, we select the main factors of the water resources carrying capacity and separate into water resources subsystem, social subsystem, economic subsystem and ecological subsystem. Then established three evaluation models to evaluate the different years of water resources carrying capacity and made the application comparison. The fuzzy comprehensive evaluation model and matter-element models are adaptable to the water carrying capacity evaluation, but the determination of weights is too subjective; The projection pursuit theory is based on the sample characteristics of their own, and without given weight of each indicator, the results is more objective. The results show that the water resources carrying capacity in Manas River basin was at V1-stage in 2000; it is at V2- stage in 2010 and V3- stage in 2020, and then the water resources carrying capacity in Manas River basin is the ideal carrying capacity status. At the same time, because of saving water technological and industry restructure adjustment, water resources carrying capacity in Manas River Basin is on a benign trend. At last, some measures of improving the water resource carrying capacity were put forward.

Abstract: This paper presents an experimental study over 204 days on anaerobic degradation of thickened waste activated sludge (TWAS) from a municipal wastewater treatment plant (WWTP). The experiments were conducted under thermophilic (55°C) and mesophilic (35°C) condition, respectively, by using the semi-continuous flow completely mixed reactors. The influent total solids (TS), hydraulic retention time (HRT) and chemical oxygen demand (COD) loading levels were around 4%, 30 days and 1.67 kg-CODCr•m-3•d-1 , respectively. During the opration period, the thermophilic anaerobic digestion process (TADP) and the mesophilic anaerobic digestion process (MADP) were stable and well-functioned without ammonia inhibition. Particulate organic matters reduction of TADP was superior to that of MADP. This result implies that TADP has higher sludge reduction efficiency than MADP. According to the simulated chemical formula of TWAS, C5.85H9.75O3.96N, and the stoichiometric equation, the methane content and the ammonia yield in the anaerobic process could be calculated, which were consistent with the experimental results. The methane yield of TADP was a little higher than that of MADP. The statistical mean values of methane content for TADP and MADP were 60.97% and 62.38%, respectively.According to paired t-test, there was a significant difference in methane content between TADP and MADP(α=0.01, n=62). Compared with the mesophilic digested sludge, the dewaterability of thermophilic digested sludge was lower.

Abstract: A combined NaOH-microwave (MW) pretreatment process was studied in order to investigate the effects of NaOH-MW pretreated thickened waste activated sludge (TWAS) on anaerobic digestion. In the NaOH-MW pretreatment studies, Uniform design was successfully applied to determine the relationship of TWAS solubilization to environmental conditions (NaOH dose, target temperature, and MW holding time) and to establish the mathematical model describing the solubilization degree to changes in these variables. The maximum solubilization ratio (85.1%) of volatile suspended solids (VSS) could be achieved at 210°C with 0.2 g-NaOH/g-SS and 35 min holding time. The biochemical methane potential (BMP) tests showed that all digesters fed with pretreated TWAS improved the methane production compared to control system, and the optimal conditions, at 170°C with 0.05 g-NaOH/g-SS and 1 min holding time, were suggested for NaOH-MW pretreatment of TWAS. In spite of the increase in the soluble chemical oxygen demand concentration and decrease in the dewaterability of digested sludge, the semi-continuous reacter fed with the pretreated TWAS without neutralization was stable and gave higher organics reductions and methane yields compared to the control.