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Li H.,Sun Yat Sen University | Lei H.,Sun Yat Sen University | Yu Q.,Sun Yat Sen University | Li Z.,China Water Resources Pearl River Planning Surveying and Designing Co. | And 2 more authors.
Chemical Engineering Journal | Year: 2010

This work evaluates the effect of low frequency ultrasonic irradiation on the sonoelectro-Fenton (SEF) oxidation process in an acid aqueous medium. Ultrasonic irradiation significantly increases the H2O2 production rate and reduces the time needed to reach the maximum H2O2 concentration. In addition, ultrasonic irradiation has a considerable effect on the degradation of the cationic red X-GRL in the SEF process. A pseudo-first-order model was used to simulate the experimental results, and this revealed that the decolorization rate increased with the ultrasonic power in the SEF process. Furthermore, both TOC removal efficiency and mineralization current efficiency were greatly promoted in the SEF process compared with the electro-Fenton (EF) process. These results prove that the SEF process is a promising technology in terms of colored wastewater treatment. © 2010 Elsevier B.V. Source

Li L.,Jinan University | Yang Y.,Jinan University | Tam N.F.Y.,City University of Hong Kong | Yang L.,National Sun Yat - sen University | And 2 more authors.
Ecological Engineering | Year: 2013

Plants are an indispensable component of a constructed wetland; however, the eco-physiological characteristics of wetland plants and their influences on wastewater treatment efficiency are still unclear. In this study, we investigated the growth features of six commonly used wetland plants, namely, Canna indica (Ci), Iris pseudacorus (Ip), Pontederia cordata (Pc), Cyperus alternifolius (Ca), Vetiveria zizanioides (Vz), and Pennisetum purpureum (Pp) that were treated with sewage. After 50 days of treatment, plants treated with diluted sewage, especially Ci and Ip, had a better growth rate than those receiving undiluted sewage. The abilities of different wetland plants to directly take up nitrogen (9.28-17.26mgg-1 DW) and phosphorus (0.89-2.18mgg-1 DW) were species-specific, but within each species, uptake was similar between diluted and undiluted sewage. Total biomass determined the total accumulation of N and P in plant tissues. The removal of pollutants, except nitrate and organic matter, was dependent on both plant species and sewage dilution. The first-order rate constants (K) for nitrate and organic matter were similar between diluted and undiluted sewage. Differences in the removal of nitrate and biochemical oxygen demand among plant species were due to differences in chlorophyll fluorescence, a photosynthetic characteristic, leading to different root lengths. The amounts of oxygen release to the rhizosphere (radial oxygen loss [ROL]) by wetland plant was directly governed by total root biomass and significantly influenced the removal of ammonia and total dissolved phosphorus via processes such as plant uptake and nitrification. The removal of total phosphorus and chemical oxygen demand resulted from the filtration by root systems. A non-species-specific significant positive correlation was found between ROL (12.50-205.25μmolO2d-1g-1 DWroot) and root porosity (9.95-32.49%). These results suggest that the root features and photosynthetic characteristic of wetland plants are important determinants of sewage treatment efficiency and could be used to select appropriate plants for constructed wetland systems. © 2013 Elsevier B.V. Source

Chen X.,CAS Qingdao Institute of Bioenergy and Bioprocess Technology | Huang C.,China Water Resources Pearl River Planning Surveying and Designing Co. | Liu T.,CAS Qingdao Institute of Bioenergy and Bioprocess Technology
Desalination and Water Treatment | Year: 2012

In this paper, polyvinylidene fluoride (PVDF) microfiltration membrane was used for harvesting microalgae Scenedesmus sp. The changes of permeation flux and OD750 of the algae medium during membrane filtration process were investigated. In order to reduce membrane fouling, both ventilation into algae medium and backwashing were adopted. The results showed that backwashing was better than ventilation to control membrane fouling. The optimized procedure was backwashing for 1 min every 20 min of continuing filtration. When the volume reduction factor (VRF) was up to 10, the recovery rate of the algae cells could reach above 90%. In addition, this paper showed that VRF and the initial concentrations of algae broth significantly affected the recovery rate. Higher VRF and higher initial concentrations of algae could make the recovery rate lower. Therefore, in order to obtain the needed recovery rate, these above factors needed to be considered. Generally, these results provided the feasible way to harvest microaglae efficiently and safely. © 2012 Desalination Publications. All rights reserved. Source

Lv J.,Key Laboratory of Northwest Water Resources and Environmental Ecology of MOE at XAUT | Zhang X.,Key Laboratory of Northwest Water Resources and Environmental Ecology of MOE at XAUT | Zhang X.,China Water Resources Pearl River Planning Surveying and Designing Co. | Shen B.,Key Laboratory of Northwest Water Resources and Environmental Ecology of MOE at XAUT | Huang L.,Key Laboratory of Northwest Water Resources and Environmental Ecology of MOE at XAUT
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2010

This paper analyzes the variation trend and primary driving factors of the annual runoffs in the Hotan oasis by adopting the moving average method, progressive average method, Spearman rank correlation coefficient method, de-trended fluctuation analysis (DFA), rescaled range (R/S) analysis and Husdorsff fractal dimension method. Results indicate a fractal dimension and a trend of no significant increasing in the Hotan oasis runoff sequence. During the period of 2000-2007, the runoff showed a short-term increase that is primarily resulted from temperature rising. © Tsinghua University Press. Source

Jing Y.,China Water Resources Pearl River Planning Surveying and Designing Co. | Wu B.,South China University of Technology
Advanced Materials Research | Year: 2011

The paper extracts two types of investigated models from frames in fire according to their horizontal deformation characteristics, and provides a simplified method to calculate horizontal deformation of frames, which can be applied to single- and multi-layers frames. Compared with the results by finite element analysis, it shows that the simplified method is a feasible method for the horizontal displacement estimation of frames in fire, and the treatment of the column restraint rigidity for multi-layers frame is appropriate. © (2011) Trans Tech Publications. Source

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