title: Heavy metal removal by combining anaerobic upflow packed bed reactors with water hyacinth ponds.
abstract: The removal of four selected heavy metals (Cu, Cd, Pb and Zn) has been assessed in an upflow anaerobic packed bed reactor filled with porous volcanic rock as an adsorbent and an attachment surface for bacterial growth. Two different feeding regimes were applied using low (5 mg L(-1) of heavy metal each) and high (10 mg L(-1) of heavy metal each) strength wastewater. After a start-up and acclimatization period of 44 days, each regime was operated for a period of 10 days with a hydraulic retention time of one day. Good removal efficiencies of at least 86% were achieved for both the low and high strength wastewater. A subsequent water hyacinth pond with a hydraulic retention time of one day removed an additional 61% Cd, 59% Cu, 49% Pb and 42% Zn, showing its importance as a polishing step. The water hyacinth plant in the post-treatment step accumulated heavy metals mainly in the root system. Overall metal removal efficiencies at the outlet of the integrated system were 98% for Cd, 99% for Cu, 98% for Pb and 84% for Zn. Therefore, the integrated system can be used as an alternative treatment system for metal-polluted wastewater, especially in developing countries.
authors.affiliation: Department of Chemistry, National University of Rwanda, P.O. Box 117, Butare, Rwanda.
authors.forename: Christian Birame
authors.initials: CB
authors.lastname: Sekomo
authors.forename: Vedaste
authors.initials: V
authors.lastname: Kagisha
authors.forename: Diederik
authors.initials: D
authors.lastname: Rousseau
authors.forename: Piet
authors.initials: P
authors.lastname: Lens
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D011232:Chemical Precipitation; D031806:Eichhornia / Q000378:metabolism*; D004553:Electric Conductivity; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D019216:Metals, Heavy / Q000302:isolation & purification*; D061005:Ponds; D013431:Sulfates / Q000737:chemistry*; D013783:Textile Industry; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D007220:Industrial Waste; D019216:Metals, Heavy; D013431:Sulfates