Treatment of landfill leachate using membrane bioreactors: A review

• Published in: Desalination Vol. 287; pp. 41 - 54
• Main Authors: Ahmed, Farah Naz, Lan, Christopher Q.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.02.2012; Elsevier
• Subjects: activated carbon; adverse effects; Ammonia; Applied sciences; biochemical oxygen demand; Biological and medical sciences; biomass; bioreactors; Biotechnology; BOD; Chemical engineering; chemical oxygen demand; COD; desalination; digestion; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General treatment and storage processes; Landfill leachate; landfill leachates; Membrane bioreactor; Membrane separation (reverse osmosis, dialysis...); Methods. Procedures. Technologies; Others; Pollution; Post-treatment; Reactors; Various methods and equipments; Wastes; Membrane bioreactor; Ammonia; COD; Post-treatment; Landfill leachate; BOD; Waste dumping; Biomass; Retention; Powder; Membrane separation; Membrane reactor; Bioreactor; Landfill Ieachate; Anaerobe; Organic loading; Chemical oxygen demand; Activated carbon; Biological oxygen demand; Micropollutant; Leachate
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2011.12.012

Landfill leachate (LFL), especially old LFL, is very difficult to treat using conventional biological processes. To this end, membrane bioreactor (MBR) has proven to be a promising alternative. The membrane separation capacity of a MBR allows the retention of most microbial cells in the reactor to maintain a high biomass concentration, resulting in an efficient biological digestion system. As a result, excellent biological oxygen demand (BOD) and ammonia removals of 90% or higher are achievable with a much shorter hydraulic residence time (HRT) and much larger organic loading rate (OLR) in comparison to conventional biological systems. MBR also allows excellent chemical oxygen demand (COD) removal (75% or higher), even with old LFL under optimized conditions. MBRs have also been demonstrated to be effective in the removal of micropollutants. Furthermore, recent developments such as anaerobic MBR and PAC (powdered activated carbon)-amended MBR have shown great potentials in LFL treatment. MBRs can provide stable performance while accommodating large variations in composition of influents and other operation conditions. However, short HRT and high ammonia concentration were found to have adverse effects. Extremely long solids residence time was also found to lower MBR performance. ► MBRs are efficient, reliable and versatile means for treating LFL, especially for old LFL. ► MBRs are efficient in ammonia, BOD/COD, and micropollutant removal. ► Effluent from MBRs are stable and of high quality, requiring only simple post-treatment. ► MBRs offer large throughput In comparison to conventional biological treatments. ► High ammonia concentration, short HRT and long SRT have adverse effects.