[Show abstract][Hide abstract] ABSTRACT: This research focused on the nutrient removal and the simultaneous CO2, CH4, and N2O emission rates of various combinations of vertical subsurface flow constructed wetlands (VSFCWs) and earthworm eco-filters (EEs) under different influent C/N ratios in synthetic wastewater. The optimal parameters for nutrient removal were influent C/N ratios of 5 : 1 and 10 : 1 as well as the combination VSFCW-EE. Relatively low values of greenhouse gas (GHG) emission rates measured in situ were obtained at a C/N ratio of 5 : 1. The emission rates of CH4 and N2O were considerably lower than that of CO2. The VSFCW-EE and EE-VSFCW combinations showed similar GHG emission results. The C/N ratio of 5 : 1 and the VSFCW-EE combination exhibited the highest nutrient removal efficiency with the lowest GHG emission rate. Wastewater nutrient removal and GHG emission were both high during summer (June to August) and low during winter (December to February).
[Show abstract][Hide abstract] ABSTRACT: The high-strength wastewater is now well known as a threat to the natural water since it is highly possible to arouse water eutrophication or algal blooms. The effects of various light emitting diode wavelengths and intensities on the microalgae biological wastewater treatment system was studied in this research. The various nutrient removals and economic efficiencies represented similar variation trends, and these variations under both high C and N loading treatments were similar too. The order for microalgae C. vulgaris reproduction in terms of dry weight and nutrient removal efficiency both were red > white > yellow > blue, under high carbon and nitrogen loading treatments, indicating that the red light was the optimum light wavelength. Furthermore, considering the optimal light intensity in terms of nutrient removal efficiency was 2500 and 2000 μmol/m2•s, while in terms of economic efficiency was 1000, 1500 and 2000 μmol/m2•s. Therefore, the optimum light intensity was found to be 2000 μmol/m2•s. In addition, the optimal experimental illumination time was determined as 120 h. The Chlorella vulgaris microalgae biological wastewater treatment system utilized in this research was able to purify the high-strength carbon and nitrogen wastewater effectively under optimum light wavelength and intensity.
Journal of Environmental Health Science and Engineering 01/2013; 11(1). · 1.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The paper explored the method of conducting HPLC-UV analysis on 3-NBA in soil. A Inertsil ODS-SP C18 column was applied in the experiment. Mobile phase was V(methanol):V(water) = 85:15, the velocity of flow was 0.5 mL/min, column temperature was 30°C. The wavelength was 391 nm. Under this chromatographic condition, 3-NBA exhibited good linear relation when its concentration is between 0.1µg/mL and 40µg/mL. The minimum detectable limit was 78ng/mL (S/N=3). The ultrasonic wave extraction method was applied to extract 3-NBA in the soil and optimal conditions for extraction were created. HPLC-UV analysis was then carried out on soil sample taken from the intersection of 320 National Road and Tong xiang Road in Jia xing. The 3-NBA content was detected to be 7.02µg/g.
Proceedings of the 2012 Second International Conference on Electric Technology and Civil Engineering; 05/2012
[Show abstract][Hide abstract] ABSTRACT: In this paper, analyses were made on the variation of the absorbency, TOC, pH and acute toxicity of the simulated wastewater which contains Acid brilliant blue G in the ozonization process. The intermediate products of the dye ozonization process were detected with GC/MS analysis method. The result showed the ozonization process contains two stages, the decoloring stage and the deep degrading stage. Acid brilliant blue G was oxidized into alcohols, aldehydes, phenols, acidamides, acids and etc, and finally was completely mineralized into CO2 and H2O. As pH changed, TOC decreased rapidly before it declined slightly. Aldehydes, phenols and acidamides account for the increase in the toxicity. As the ozonization proceeded, after 24 min, the toxicity of the wastewater decreased.
Electronics, Communications and Control (ICECC), 2011 International Conference on; 01/2011
[Show abstract][Hide abstract] ABSTRACT: Optimization of the molecular geometry of 209 polychlorinated diphenyl ethers (PCDEs) and diphenyl ether (DE) were carried out at the B3LYP/6-31G* level with Gaussian 98 program. Based on the theoretical linear solvation energy relationship (TLSER) model, the obtained structural parameters were taken as theoretical descriptors to establish the first novel QSPR model (I) for predicting subcooled liquid vapor pressure (PL) of PCDEs. The model (I) achieved in this work contains three variables: most negative atomic partial charge in molecule (q−), dipole moment of the molecules (μ) and mean molecular polarizability (α), of which r2=0.988, SD=0.134. Meanwhile, it was found that there was significant correlation between the Cl substitution positions and some structural parameters. Consequently, the numbers of Cl substitution positions were also taken as theoretical descriptors to establish the second novel QSPR model (II) for predicting PL of all PCDE congeners, of which r2=0.991, SD=0.112. In addition, the t-values of two models are both large and the variation inflation factors (VIF) of variables herein are all less than 5.0, suggesting significant statistics of the PL predicting models. And the results of cross-validation test also showed that the second model exhibited optimum stability and better predictive power. Moreover, results of prediction were further compared with data from similar studies by semi-empirical PM3 method, molecular connectivity indices (MCIs) method and molecular descriptors method.
[Show abstract][Hide abstract] ABSTRACT: Polycyclic aromatic hydrocarbon (PAH) and nitrated PAH (NPAH) products are toxic. Thus, determination of their concentrations is of great interest to researchers of soil and water pollution control. In this work, soil samples, surface water samples, and groundwater samples were collected, and the concentrations of 16 priority PAHs and 15 NPAHs were determined using an HPLC-ultraviolet detector. Results showed that the total PAH concentrations ranged within 489.69–1,670.11 ng/g (average = 905.89 ng/g) in soil samples, 4.00–23.4 μg/l (average = 9.84 μg/l) in surface water samples, and 2.14–22.3 μg/l (average = 8.37 μg/l) in groundwater samples. The NPAH concentrations were one to two orders of magnitude lower than the PAH concentrations and ranged within 22.72–128.70 ng/g (average = 63.88 ng/g) in soil samples. 2-Nitropyrene and 6-nitrochrysene were the most abundant compounds, accounting for about 14.3 and 26.5 %, respectively. Source analysis revealed that most PAHs originated from coal combustion around the study area, whereas NPAH studies suggested that the primary emission of gasoline engines and daytime OH reactions were the dominant sources of these compounds.