The effect of landfill leachate composition on organics and nitrogen removal in an activated sludge system with bentonite additive
- 31 October 2007
- journal article
- Published by Elsevier BV in Journal of Environmental Management
- Vol. 85 (1), 59-68
- https://doi.org/10.1016/j.jenvman.2006.08.001
Abstract
A pre-denitrification activated sludge system (AS) without internal recycle was used in lab-scale studies of landfill leachate treatment. A bentonite supplement at a ratio of 1:4 (mineral : biomass) was used to ensure high sludge settling levels and to serve as a micro-organisms carrier. The system was operated within different parameters such as hydraulic retention time (HRT), ammonia loading rate (ALR) or external recycle ratio, which was adapted to treat varying leachate concentrations of COD and ammonia, ranging from 1020 to 2680 mgO(2)l(-1) and 400-890 mgNH(4)-Nl(-1) respectively. The nitrification was complete and ammonia oxidation reached 99%; this was obtained while the ALR did not exceed 0.09 g NH(4)(+)-Ng(-1)MLVSS d(-1) and HRT was not lower than 1 day (in the aeration reactor). The performance of denitrification was successfully improved by controlling the external recycle rate, when the BOD(5)/N ratio in the raw leachate was 4.1. Consequently, N-removal of up to 80% was achieved. A 10-fold decrease in the denitrification rate was obtained at a BOD(5)/N ratio of 0.5. The efficiency of COD removal varied significantly from 36% to 84%. The positive effect of bentonite addition was determined and is discussed based on preliminary studies. The experiments were carried out in fill-and-draw activated sludge with bentonite; the biomass ratio was 1:2. The activated sludge with bentonite was fed with a synthetic high ammonia and organic-free medium.Keywords
This publication has 32 references indexed in Scilit:
- Enhanced ammonia nitrogen removal using consistent biological regeneration and ammonium exchange of zeolite in modified SBR processWater Research, 2003
- Simultaneous adsorption and biological treatment of pre-treated landfill leachate by fed-batch operationProcess Biochemistry, 2003
- Comment on “The effect of kaolin particles on the behavior of nitrifying activated sludge units”Bioresource Technology, 2003
- Wastewater treatment in a hybrid biological reactor using powdered minerals: effects of organic loading rates on COD removal and nitrificationProcess Biochemistry, 2002
- Biogeochemistry of landfill leachate plumesApplied Geochemistry, 2001
- Application of pressure-driven membrane techniques to biological treatment of landfill leachateProcess Biochemistry, 2001
- Ammoniacal nitrogen removal from water by treatment with clays and zeolitesWater Research, 2000
- Floc agglomeration and structuration by a specific talc mineral compositionWater Science & Technology, 1997
- Improving settling dynamics of activated sludge by adding fine talc powderWater Science & Technology, 1996
- Maintaining nitrite build-up in a system acclimated to free ammoniaWater Research, 1989