PILOT PLANT ANALYSIS OF AN INTEGRATED PROCESS FOR THE TREATMENT OF LANDFILL LEACHATES
Special Symposium - EPIC-1: European Process Intensification Conference - 1
EPIC-1: Poster Session (EPIC - Poster) - P1
Keywords: Advanced oxidation processes, Fenton´s reagent, Landfill leachate, Membrane ultrafiltration
Abstract
Landfill is one of the most widely employed methods of disposing of municipal solid wastes (MSW). About 57 % of the total MSW generated in the USA in 2000 was disposed of in landfills (Kurniawan et al., 2006). One of the most serious environmental problems related to landfill is the generation of leachates. These aqueous effluents contain large amounts of organic compounds, heavy metals, ammonium and inorganic salts. Their characteristics vary depending on the kind of solid wastes, the age of the landfill and climatic conditions. Consequently, landfill leachates need to be treated to meet the quality standards before discharge.
The use of Advanced Oxidation Processes (AOPs) is a promising alternative for wastewater remediation, mainly due to the capacity to improve the removal of recalcitrant organic compounds or to transform them into more easily biodegradable substances (Wang et al., 2003). Fenton´s reagent (Fe2+/H2O2) is one of the most common AOPs. It has been successfully applied to the treatment of different industrial wastewaters and landfill leachates. To complete the treatment, neutralization and sludge separation are required. However, when compared with bench scale research, the reported applications on pilot plant scale are scarce (Zhang et al., 2006).
The aim of this work is to analyse and operate a pilot plant of an integrated process for the treatment of landfill leachates that combines Fenton oxidation and ultrafiltration with submerged membranes evaluating the efficiency in the reduction of organic matter expressed as COD.
The leachate came from a municipal landfill site located in northern Spain (Cantabria). It generated 800 m3 app. leachate/day with an average initial COD concentration of 1500 mg/L. The plant consisted of a 100 L Fenton reactor, a 200 L neutralization tank and a ZeeWeed 10 ultrafiltration unit equipped with an immersed hollow-fiber membrane module of 0.93 m2 surface area.
Fenton oxidation was carried out during 60 minutes of reaction time and different reagents dosages were studied. Neutralization was performed either with NaOH or Ca(OH)2. Submerged membranes worked with a permeate flow up to 50 L/h without fouling problems with an amount of total solids in the tank higher than 3.5 g/L. Reductions up to 75% COD and complete colour removal were achieved. Characterization of the residual COD showed organic acids as main refractory compounds after the treatment.
The results obtained in the operation of the pilot plant show the efficiency of the integrated process that uses Fenton´s oxidation in combination with submerged ultrafiltration membranes in the remediation of recalcitrant waste effluents, landfill leachates.
Acknowledgments: Finantial support from the Spanish Ministry of Environment (project 2.5-216/2005/3-B and 546/2006/2.2-5) is gratefully acknowledged.
References
Kurniawan, T.A., Lo, W.H., Chan, G.YS. (2006). Radicals-catalyzed oxidation reactions for degradation of recalcitrant compounds from landfill leachate. Chemical Engineering Journal 125, 35-57.
Wang F., Smith D.W. and Gamal M. (2003). Application of advanced oxidation methods for landfill leachate treatment – A review. Journal of Environmental Engineering Science 2, 413-427.
Zhang H., Choi H.J., Huang C.P. (2006). Treatment of landfill leachate by Fenton´s reagent in a continuous stirred tank reactor. Journal of Hazardous Materials 136, 618-623.
Presented Wednesday 19, 13:30 to 14:40, in session EPIC-1 Poster Session (EPIC - Poster) - P1.
