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Yang Y.Y.,Beijing University of Technology | Ren X.J.,Environmental Protection Institute of Light Industry | Li S.C.,Beijing University of Technology | Zhu L.M.,Beijing University of Technology | Tian S.Y.,Beijing University of Technology
Applied Mechanics and Materials

A new hydrocyclone and gas-flotation device was designed and tested for the treatment of the wash water containing the flocs. The device separates particles and removes flocs simultaneously. The gas-generator equipment can produce a large number of micro-bubbles, and the bubbles adhere to the impure flocs particles. This makes the density of the 'bubble-floc' less than that of water, and their buoyancy enables particle separation and removal of suspended flocs. To achieve a high efficiency of flocs removal and particle separation, some of the factors that influence the separation efficiency (such as the gas-liquid pressure difference, gas-liquid ratio, underflow split ratio, water pressure, inlet flow rate, and the contact time of the gas and particles, bubble size, and number of bubbles) were investigated. The results showed that there is an optimum combination of multi-dimensional parameters; good particle separation and a high efficiency of flocs removal were achieved. © (2013) Trans Tech Publications, Switzerland. Source

Liu G.,Chinese Research Academy of Environmental Sciences | Liu G.,Shanxi Agricultural University | Bi R.,Shanxi Agricultural University | Zhang C.,Chinese Research Academy of Environmental Sciences | And 3 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae

Uncertainty in site investigation and the determination of contamination boundary at large-scale contaminated sites is a critical issue in China. In order to test the influence of different prediction models on the determination of contamination boundary in a coking plant contaminated by benzo(a)pyrene (BaP), three spatial interpolation models, Inverse Distance Weighting model (IDW), Johnson's ordinary lognormal kriging model (OLKM), and Combination Prediction Model (CPM), were employed to compare their efficiencies and precisions in determining site contamination boundary. A recommended value 0.4 mg·kg-1 for BaP was used as the reference standard based on the Beijing Screening Levels for Soil Environmental Risk Assessment of Sites. The Results showed that the contamination areas calculated by IDW, OLKM, and CPM were 70.15%, 44.78% and 57.06%, respectively. The CPM was found to be more accurate than the other two models in predicting the actual pollution situations of the contaminated site. The area on the top-right corner of the site with less sampling points and the area in the mid-bottom part with high levels of contamination showed the largest standard errors based on the prediction standard errors map. This study gives useful references for dealing with uncertainty in determining remediation boundary of contaminated sites. Source

Liu G.,Shanxi Agricultural University | Liu G.,Chinese Research Academy of Environmental Sciences | Bi R.-T.,Shanxi Agricultural University | Wang S.-J.,Chinese Research Academy of Environmental Sciences | And 3 more authors.
Chinese Journal of Applied Ecology

Statistical characteristic analysis of pollutants in contaminated sites can help identify the origin, generation, and spatial variation of different pollutants, and can reduce the uncertainty of site survey data. Taking a large and abandoned contaminated coking site of China as the object, 114 surface (0-50 cm) soil samples were collected, with the statistical and spatial characteristics of 16 priority PAHs (ΣPAHs) analyzed. The descriptive statistical analysis indicated that the ΣPAH levels varied significantly, and the data were severely skewed. The correlation matrix (CM) and principal component analysis (PCA) showed that the extracted first two principal components (PCs) could effectively represent the whole site pollution data. Four pollutants, i. e., Baa, Bbf&Bkf, Bap, and Inp, were selected for trend analysis and spatial local variance analysis. In the east-west and north-south directions of the site, the pollution showed a low-high-low trend. The variation coefficient of pollution for the site was higher in the central, northwest, and southwest regions, while lower in the other regions. Source

Wei W.X.,Environmental Protection Institute of Light Industry | Quan T.,Environmental Protection Institute of Light Industry | Quan T.,Shanxi Agricultural University | Wang Y.,Environmental Protection Institute of Light Industry | And 3 more authors.
Advanced Materials Research

Contaminated sites remediation is one of the hot points in environmental protection fields. Therefore, an important research project is how to expediently determine the bound and level of pollution of contaminated sites. This may help to decide on a timely and accurate rescue plan so as to minimize the costs and to improve the effect of restoration. This is also the basis of contaminated sites remediation acceptance. There are many influencing factors to confirm the remediation areas on contaminated sites. Studies show that three-dimensional interpolation method is effective tool to delimit the pollution scope. Different three-dimensional interpolation methods have different results in contaminate distribution prediction and directly affect the boundary of contamination. This paper selects one specific case with heavy metal lead contamination to study three-dimensional interpolation methods. The three-dimensional stratigraphic model is established for uncertainty analysis and error analysis in the grid through Kriging, IDW (Shepard) and nearest neighbor interpolation method. Results show that 40m*40m grids have the highest accuracy of stratigraphic simulation. Nearest neighbor interpolation method is most suitable for stratigraphic model building. Kriging interpolation method is more suitable for constructing three-dimensional pollutant prediction model. On the basis of above, this text established one distribution prediction model of soil lead contamination, and calculated the contaminated earthwork quantity under different remediation goals. Finally, the paper achieved three-dimensional visualization of the site soil contamination. This study can be directly applied to the actual site remediation decision process, and is helpful for the contaminated sites evaluation and restoration in the future. © (2014) Trans Tech Publications, Switzerland. Source

Ren X.,Environmental Protection Institute of Light Industry | Liu D.,Environmental Protection Institute of Light Industry | Wu Y.,Environmental Protection Institute of Light Industry | Zhang Z.,Environmental Protection Institute of Light Industry | And 3 more authors.
Chinese Journal of Environmental Engineering

A process combined coagulation-nanofiltration was used for advanced treatment of deinking secondary effluent. The experimental results showed that when the amount of PACl was 100 mg/L, the optimal pollutant removal efficiency could be obtained with turbidity and colourity removal rate of 91% and 74%, respectively. After coagulation, the deinking wastewater was further treated by four nanofiltration membranes with same material but different molecular weight cut-off. The final effluent quality met the industrial boilers criteria specified in the Standards of Reclaimed Water Quality (SL368-2006). Source

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