Biological treatment for removal of organic material and ammonium from leachate at low temperatures

• Published in: Waste management & research Vol. 17; no. 6; pp. 487 - 492
• Main Authors: Kettunen, Riitta H, Keskitalo, Pertti, Hoilijoki, Taina H, Rintala, Jukka A
• Format: Journal Article
• Language: English
• Published: 01.12.1999
• Subjects: Activated sludge process; Ammonium compounds; Anaerobic digestion; Biochemical oxygen demand; Biological sewage treatment; Bioreactors; Chemical oxygen demand; Cost effectiveness; Nitrification
• ISSN: 0734-242X; 1399-3070
• DOI: 10.1034/j.1399-3070.1999.00074.x

The biological anaerobic-aerobic treatment of medium-strength municipal landfill leachate (COD (chemical oxygen demand) 1500 to 3200 mg l super(-1); BOD sub(7) (biological oxygen demand) 1200 to 1900 mg l super(-1); NH sub(4)-N 80 to 270 mg l super(-1)) was studied by using a pilot-scale Upflow Anaerobic Sludge Blanket (UASB) reactor (13 to 28 degree C) and laboratory-scale activated sludge reactors (5 to 11 degree C). In the sequential process, 80 to 90% COD removal was achieved with an effluent COD of 250 to 350 mg l super(-1) and a BOD sub(7) of <10 mg l super(-1). Most of the organic material was removed during anaerobic pretreatment, and more than 50% COD removal was obtained at 13 degree C. The aerobic stage served as an ammonium removal and a polishing step. More than 90% of ammonium was efficiently removed by nitrification even at 5 degree C. The anaerobic-aerobic treatment produced effluent fulfilling the official requirements. Furthermore, the sequential process seems sustainable and cost effective for leachate treatment at low temperatures. Based on a preliminary design, leachate treatment costs were estimated at 3.1 to 3.3 EUR m super(-3) in the sequential process. This compares with the option of discharging leachates into a sewer system. Both the discharge fee and the construction and operational costs of a transfer sewer are considered.