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Treatment of Landfill Leachate by Integrated Horizontal-Flow Constructed Wetlands

Due to various components within the landfill sites, the water qualityof landfill leachate, which has high consistency of COD, BOD and nutrients, is unsteady. Using traditional sewage treatment plant to treat leachate should be designed and built to fit the unsteady water quality, which is usually time consuming and high expenditured. Therefore, application of constructed wetland treatment systems as altanatives may solve such kinds of problems
According to the experimental results of this study, referring to the effect of cleaning the controlling substances, the SSF (sub-surface flow system) constructed wetland system performed better than the FWS (free-water surface system) one, which was because FWS was usually operated in an opening water areas, which exposured to the air causing stink in the inflow site of influent, and meanwhile caused problems of virus-transmitting mosquitoes. . Thus, it was suggested to use SSF system in treating landfill leachate.
In this study, we found that the average removal efficiencies of pollutants in the leachate were high in the constructed wetland systmes (phosphate 73%, total phosphorous 70¢H, total nitrogen 57%, NH3-N 77¢H, COD 43% ). In addition, the BOD in the effluent from the systems could reach the outflow standard guideline in Taiwan (30 mg/L). Hence, using constructed wetland systems to solve those problems arisen from landfill leachate is expandable.
We also found that the aquatic plant species of reed (Phragmites australis) that we used in this study could not grow well and was invaded by aphid due to the limitary environment in the landfill site and lack of biodiversity, which could not generate a good natural food chain. On the other hand, it was found that the plant species of evergreen (Dracaena sanderiana) could grow healthily and present high removal efficiencies for pollutants. Since the leachate was lack of biodegradable organic carbon sources used for denitrification, in the final test run of this study, we run an experiment of adding organic carbon sourcecs (fructose and molasses) into the constructed wetland systemis to test its effect on denitrification. The experimental results showed that the addition of organic carbon sources could significantly increase the efficiencies of denitrification to let more nitrate removed from the leachate, especially for molasses, which could increase the denitrification efficiency above 90%.
Date13 October 2006
CreatorsChen, Yi-ling
ContributorsWen-Chien Kuo, Lei Yang, Jimmy C. M. Kao, Bang-Fuh Chen
Source SetsNSYSU Electronic Thesis and Dissertation Archive
Detected LanguageEnglish
Rightsoff_campus_withheld, Copyright information available at source archive

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