Advanced Materials Research Vols. 347-353

Abstract: The main objectives of this study were to describe the municipal solid waste management, leachate characteristics of China landfills, and to summarize the present research of leachate treatments in china such as biological treatment, physical and chemical treatment and land treatment. In the survey of leachate from landfill in Chinese megapolis, the quality is characterized by chemical oxygen demand (COD) of 1500-80000 mg/L, biochemical oxygen demand (BOD) of 200-35000 mg/L, ammonia nitrogen (NH3-N) of 50-2400 mg/L, total nitrogen of 80-2600 mg/L, suspended solid of 30-7000 mg/L and pH value of 5-7.8. In engineering practices of China, the biological systems are usually adopted. Meanwhile, as far as the special quality of leachate is concerned, some chemical treatments are used as the pre-treatment or post-treatment to promote the effluent or improve the biological degradability of leachate.

Abstract: Water structure present in sewage sludge with different moisture content was analyzed by differential scanning calorimeter(DSC).The sharp endothermic peaks that appeared at 6.14°C(95.87%wet basis),5.22°C(87.20%wet basis),1.33°C(71.20%wet basis).The calculation results , amount of bound water based on peak temperature and peak area, could account for stick phase of sewage sludge combined with SEM analysis results. Finally,mechanical mechanism of different phases(liquid phase, sticky phase, granule phase) were tentively described by schematic diagrams.

Abstract: The flocculants of fly ash(FA) and modified fly ash (mFA)were investigated in this study to evaluate their flocculation efficiencies in freshwater containing harmful algal blooms(HABs). The experimental results show that the efficiency of flocculation can be prominent improved by mFA.It was found that the fly ash modified by hydrochloric acid could form network structure bundle, algal cells were wrapped up through netting and bridging effect. So the method that removal of HABs with modified fly ash is low cost with high efficiency

Abstract: Runoff, sediment yield and infiltration process of shrub plots were studied under rainfall intensities of 45, 87 and 127 mm/h with 20° slope gradient using simulated rainfall experiment. The results showed that cumulative runoff and cumulative sediment yield of shrub plot had an obvious positive correlation with rainfall time. Under rainfall intensity of 45 mm/h, runoff and sediment yield of shrub plot kept a constant level. Under rainfall intensity of 87 mm/h, runoff kept a fluctuant increase, whereas sediment yield basically kept steady. Under rainfall intensity of 127 mm/h, runoff and sediment yield of shrub plot increased evidently due to the formation of erosion pits. Infiltration rate of shrub plot had a negative relation with runoff as well as sediment yield.

Abstract: The recovery of vanadium and copper from the precipitate and the waste water formed in the removing vanadium from crude TiCl₄ with copper wire was investigated. For the processing of the precipitate, the brief flow includes dechlorinating, H₂SO₄ leaching copper, crystallization blue vitriod, as well as NaOH leaching vanadium, followed by ion exchange enrichment vanadium; the copper and vanadium leaching percent was 88.4% and 84.3%, respectively. For the processing of the waste water, the coprecipitation process was used, after that the discharged wastewater could meet with the National Standards. The precipitate formed in coprecipitation process was first leached by NaOH solution for recovery of vanadium, and then the leach cake containing copper was leached by H₂SO₄ solution for recovery of copper; the overall vanadium and copper recovery was 79.5% and 86.8%, respectively.

Abstract: A field experiment was conducted to remove the potential eutrophication effect of N and P from rural wastewater (RW) during the whole rice growing season of 2010. Commercial fertilizer and RW were applied to furnish 40 kg P ha-1except CK. Results showed TN concentration of the floodwater in the paddy wetland system decreased quickly after transplanting, rosed significantly (P ≤ 0.05) after two N topdressings, and then decreased gradually as the following sequences: SW > GW > DW > BW > CK. Total P (TP) concentration had significantly declined after P application, from October 15 there were no significant increases in TP concentration in the floodwater. Meanwhile, the yield for CK was significantly less (P ≤0.05) than SW, GW, DW, and BW, with the yield of BW significantly greater (P ≤ 0.05) than other treatments. It is feasible to remove N and P from RW by the paddy wetland system and can be widely used to improve the yield of rice.

Abstract: A typical printed circuit boards (PCBs) has been investigated by using thermo-gravimetric analyser to study its pyrolysis characteristics, the results indicate that the maximum weight loss rate occurs at temperature between 320°C and 360°C. A higher heating rate results in higher initial, final, peak temperature, and a longer process of significant weight loss. At the same pyrolysis temperature, heating rate has little effect on the total weight loss. In addition, 1kg PCBs based FR-4 was pyrolyzed in a fixed-bed reactor. The pyrolysis residues are very friable, the organic, glass fiber and metallic fractions can easily be separated, and the electrical components can easily be removed from the remains. Considering energy-saving, better control and design of the pyrolysis process, the optimal pyrolysis parameters were suggested at heating rate 10°C/min, final pyrolysis temperature 500°C and holding time 30 min.

Abstract: A sequencing batch reactor was employed to treat ammonia wastewater, the pH, DO and OUR were adopted to monitor the start of short-cut nitrification. The results showed that the start of short-cut nitrification was achieved in 31days, ammonia consumption rate was higher than 90% and nitrite accumulation rate was higher than 85%, when pH, DO and OUR were applied to monitor and determine the aeration time, under the condition of temperature was 30°C. With ammonia shock loading conditions, OUR curve couldn’t indicate the end of short-cut nitrification exactly. But real-time control using pH and DO could achieve a stable shortcut nitrification under steady stage and ammonia load shocking stage.

Abstract: _{Subscript textSubscript text}A series of Au/CeO₂ catalysts were synthesized and evaluated for formaldehyde catalytic combustion oxidation. In Au/CeO₂ catalysts, CeO₂ supports with different structure,Au/Macroporous-CeO₂ is found to be superior catalyst for formaldehyde catalytic oxidation. According to the analysis of transmission electron microscopy (TEM), the pore size of Macroporous-CeO₂ is broader than that of mesoporous SBA-CeO₂ support, which could make the active species gold adequately disperse as small nanoparticles, furthermore, it is most noticed that macroporous CeO₂ support is benefit to mass transfer comparing with mesoporous SBA-CeO₂ and ordinary power CeO₂.

Abstract: Nine fungal strains, previously isolated from produced wastewater in Liaohe oilfield in China, were screened for the study on the biodegradation ability of heavy oil in a batch of shake-flask culture. Among them, fungi F1, F4, F5 and F7 showed relatively higher abilities for the biodegradation of heavy oil. Heavy oil removal rates after 56 days by the above four strains were 57.82 %, 63.30 %, 36.46 % and 45.63 %, respectively. In addition, the biodegradation process followed the first- order kinetics, and the half- life of heavy oil from long to short order was F5>F7>F1>F4. By contrast, fungus F4 was the highest effective strain for heavy oil degradation. Degradation rates of petroleum fractions by different fungal strains varied significantly. And the highest degradation rates of alkanes was 42.99 % by F5, and correspondingly, that of aromatics with 37.87 % by F1, and that of colloids and asphaltenes with 46.42 % by F4.