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Ling H.,Peking University | Lu A.,Peking University | Wang C.,Peking University | Li Y.,Peking University | And 3 more authors.
Clays and Clay Minerals | Year: 2011

Landfill leachate is one of the most difficult effluents with which to deal from an environmental perspective because of its concentration and complex composition, including refractory and toxic components such as heavy metals or xenobiotic organic compounds. The objective of the present study was to use organically modified bentonite (OMB) to dispose of landfill leachate >10 y old. The OMB was synthesized using a new method, which removed four steps (filtering, washing, drying, and grinding) from the traditional process. After treatment using OMB, the chemical oxygen demand concentration (COD concentration, an index of the organic pollutants in the landfill leachate, was determined using the potassium dichromate method) of the landfill leachate sample decreased from 2400 to 245 mg/L in 5 h, i.e. the organic pollutants reduction efficiency was as high as 90%. Gas chromatography-mass spectrometry results indicated that most of the organic compounds were removed during the process. The modified and unmodified bentonite contained in the OMB deal with the hydrophobic and hydrophilic organic pollutants, respectively, resulting in significant degradation of the leachate. The study results have provided a new cost-effective method for treatment of landfill leachate. Source

Zhang Y.,Tsinghua University | Yue D.,Tsinghua University | Lu X.,Beijing Environment Sanitation Engineering Group Co. | Zhao K.,Tsinghua University | Ma H.,Tsinghua University
Journal of Material Cycles and Waste Management | Year: 2015

The significance of humification pathway as promoted by metallic oxides has previously been well investigated using a model system containing humus precursors. Metallic oxides, co-existing with organic matter in nature, are capable of promoting humification of organic matter to different degrees. This study is an investigation into the role of ferric oxide in the process of humification, based on the degree of darkening for humus precursors. Glucose (Glu), glycine (Gly) and catechol (Cat) were introduced as humification model precursors, and the role of ferric oxide in different periods of humification was discussed by characterizing humification degree in terms of dissolved organic carbon, ratio of Fulvic acids (FA) to Humic acids (HA), and E600. Valence changes of Fe were analyzed using X-ray photoelectron spectroscopy. The results showed that ferric oxide was effective on the conversion from FA to HA, and the effectiveness grew as the ferric oxide concentration increased. A higher pH value was more conducive to form dark substances. Amounts of Fe with various valences changed remarkably after humification, suggesting that ferric oxide was involved in the humification reaction. © 2015 Springer Japan Source

Wu S.-X.,Beijing Environmental Sanitation Engineering Research Institute | Dai Z.-F.,Beijing Environmental Sanitation Engineering Research Institute | Su Z.-H.,Beijing Environmental Sanitation Engineering Research Institute | Zhou X.-F.,Beijing Environment Sanitation Engineering Group Co. | And 5 more authors.
Huanjing Kexue/Environmental Science | Year: 2013

Odor pollution of landfill site is a serious problem accompanied with the urbanization process that influences city life. Generally, odor emission points in landfill boundary are detected by experience, but the pollution intensity, distribution and variation in the scope of landfill boundary are difficulty to describe. In this research, odor emission points were disclosed with equal odor concentration curves that were delineated using electric nose and GPS instrument. The leakage of landfill gas and exhaust emission from biogas incineration torch was the main cause of the odor pollution in landfill area. Gas production evaluation suggested that the improvement of landfill gas consumption is the key point to control the odor pollution at the landfill site. Source

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