Advanced Materials Research Vols. 255-260

Abstract: Based on ASM2d, establish a mathematical model to describe the transformation of different components including carbon, nitrogen and phosphorus, to explore the consistency between simulation and observed values of different compunents, to anlyze the kinetics and stoichiometric parameters in MUCT process. The results showed that, the q_PHA, K_A, K_PP, Y_PO4, μ_AUT and η_NO3 were 2.90gX_PHAg^-1X_PAOd^-1, 3.85gX_PHAg^-1X_PAOd^-1, 1.35gX_PHAg^-1X_PAOd^-1, 0.35, 1.6 and 0.8, respectively. The typical parameters given by the ASM No. 2d were used as others kinetic and stoichiometric parameters.

Abstract: Three typical external carbon sources (i.e. leachate, hydrolysates from primary sludge and starch solution) with regard to the denitrification process were investigated respectively in sequencing batch reactors (SBR) and their denitrification properties were compared to provide the optimum substrate suited for nitrogen removal processes. The variations of nitrogen were examined and nitrate utility ratio as well as carbon consumption rate was exhibited, denitrification kinetics regarding leachate was also analyzed by use of zero-order kinetic model. The experimental results indicated that the similar denitrification trend was achieved between hydrolysates from primary sludge and starch solution other than leachate as carbon source in denitrification system. The nitrate was not entirely degraded and the nitrite generated permanent accumulation. Compared with other carbon sources, leachate in steady operation showed the highest nitrate removal concentration and rate in phase I with an average of 13 mg/L and 86%, respectively. In phase II, the maximum nitrate and carbon decomposition rates were 0.088 g N/g VSS•d and 0.848 g TOC/g VSS•d respectively occurring at leachate as substrate. Thus, stable leachate was considered as the most suitable carbon source in comparison with other substrates.

Abstract: Exterior wall insulation technology is an effective way on saving energy. By using this technology, building envelope insulation performance can be improved, energy is saved and wall structure can also be improved which extends the life of building envelope. So it is worthy to further promoting the use of the emerging technology. This article discusses the advantages and types of insulation, and some problems need to be noted when constructing in order to ensure the quality of the wall insulation.

Abstract: Methyl tert-butyl ether (MTBE) has been added into fuel extensively as oxygenate. Due to high water solubility, MTBE is not easy to be removed from contaminated groundwater. Common control techniques for MTBE include combustion, adsorption, biological treatment and air stripping etc. In this study, the V-doped TiO₂ was synthesized by modified sol-gel method and its’ photocatalytic degradation effect on MTBE irradiated under visible (λ= 419 nm) was evaluated. The crystal structure of V-doped TiO₂ was found mainly anatase using the X-ray diffractometer (XRD)and its size was estimated about 20 nm using field-emission scanning electron microscope (FE-SEM). According to the brunauer emmett teller (BET), the surface area of doped Vanaduium on TiO₂ decreased due to the decrease of porodity. Comparing with the response for visible light, the V-TiO₂ complex had significantly efficiency of photocatalytic degradation for MTBE under visible light irradiation and the destruction removal efficiency (DRE) of photocatalytic degradation was up to 83 % for 10 ppm of MTBE under visible light irradiation.These evidences suggest that the composite V-TiO₂ under visible light irradiation can be widely used to treat other organic hazardous or recalcitrant pollutants in the practical contaminated groundwater.

Abstract: The magnetic photocatalysts (MPCs) can provide both a high specific surface area and an alternative for recovering used catalyst from treated water by the application of a magnetic field. In this study, the Fe₃O₄ particles were synthesized by co-precipitation under alkaline condition. After annealing, the suspension of magnetite particles can be separated by magnet. The magnetite particles were dried and then mixed with TTIP (titanium tetraisopropoxide) for sol-gel method. The MPCs were then achieved after dried and calcined in 300°C. The MPCs synthesized in this study can be separated from treated water by a simple magnet. The photocatalytic abilities of synthesized MPCs were evaluated by measuring the residual methylene blue (MB) amounts after irradiation under a light intensity of 1.0 mW/cm² at 365 nm. The results showed that the synthesized MPCs had good crystallinity of anatase and magnetite. The MPCs can be separated by a simple magnet and did not reduce the photocatalytic abilities significantly. With the advantages of reusability, durability, and separability the synthesized MPCs in this study appear a good alternative for water treatment and widely other potential applications. A MPC with an optimal Fe/Ti ratio and smaller particle size is expected to perform a more practical alternative on water treatment in the future.

Abstract: Poly-THF production wastewater was treated by Liquid-liquid extraction method, chloroform as extraction agent. the influences of phase ratio and temperature, extraction equilibrium time on wastewater treatment effect have been studied. The results showed that, under the operating conditions of temperature of 25°C, phase ratio 1:1 and extraction equilibrium time 40 min, COD_Cr removal efficiency above 75% is achieved, in order to lay the foundation for subsequent treatment.

Abstract: Xikeng Reservoir is one of the major water supply reservoirs in Shenzhen. The water quality of Xikeng Reservoir has been poor, with much of the pollution coming from nonpoint sources. An innovative low impact development type of BMP called the BioBox was used at the Administration Building parking lot location, as a research site and demonstration project to show how small alterations to parking lot designs can dramatically decrease pollutant loads. Manual samples were collected during storm events and analyzed for total suspended solids (TSS); five-day biochemical oxygen demand (BOD₅); ammonia nitrogen (NH₃-N), and total phosphorus (TP). In summary, the ranges of removal rates of the BioBox are: TSS 70% - 90%; BOD₅ 20% - 50%, and ammonia and phosphorus 30% - 70%. The BioBox system effectively reduced the concentrations of pollutants in the parking lot runoff.

Abstract: The experiment on phosphorus recovery in PTMEG wastewater by crystallization was studied. The influences of molar ratio, precipitation time, stirring speed on the amount of crystals and structure characterization have been studied. The results indicated that under molar ratio 1.5:1, stirring speed about 200r/min and precipitation time 2h, PO₄^3- removal ratio above 85%, the morphology of obtained crystals was related to the stirring speed and the X-ray diffraction pattern showed that the crystals had a high purity.

Abstract: In this study, Chlorophytum comosum was used to restore the artificially polluted soil by pot-planting. The results showed that the sensitivity of soil enzymatic activities was ranked as follows: urease > invertase > phosphatase > catalase, as their activities were only 25.71%, 33.33%, 37.88% and 55.49% compared to CK. The electrical conductivity (EC) value of soil increased from 98.3 to 608.7 µs·cm^-1 with the increase of copper (Cu) concentration in soil, but the organic matter had no significant difference between different treatments. The bioaccumulation coefficients (BC) and translocation factors (TF) value of C. comosum were both above 0.5 when Cu concentration in soil was up to 500mg·kg^-1, which indicated that there might be an excellent and transport mechanism in C. comosum. In conclusion, C. comosum is a potential ornamental plant in recovering Cu-contaminated soils.

Abstract: Levels of organic matters in raw water from Huangpu River and treated water from different processes have been investigated. Dissolved organic carbon (DOC) and assimilable organic carbon (AOC) have been determined on ultrafiltrate (UF) (MW cut-off of 1K and 10K Daltons) samples. The organics in raw water are majority of lower MW (<1K Daltons) fractions. The conventional treatment processes are effective in removing higher MW (>10K Daltons) organics, while granular activated carbon (GAC) adsorption can reduce organics with lower MW significantly. The lower MW fractions correspond to 60%~70% of the AOC in raw and treated waters, and much higher than other MW fractions. This indicates that the AOC is mainly related to organics with lower MW. In order to decrease AOC level to achieve biostability in drinking water, the processes which can reduce lower MW organics effectively must be employed.