Combining Anerobic Degradation and Chemical Precipitation for the Treatment of High Strength, Strong Nitrogenous Landfill Leachate

Treatment of organics and ammonium from sanitary landfill leachate was investigated using a combination of anaerobic treatment and magnesium ammonium phosphate precipitation (MAP) processes. The effect of organic loading rate (OLR) was evaluated for the removal of COD and BOD 5 in an anaerobic treatment by anaerobic sludge blanket (UASB) reactor. The UASB reactor removed organics successfully. OLR has a significant effect on the reactor performance and the maximum COD removal was 90% at an OLR of 9 kg COD/(m 3 d). On average, 86.3% of COD and 95.3% of BOD 5 were removed at a steady state of anaerobic treatment. MAP precipitation was performed in order to decrease the ammonium concentration of anaerobically-treated leachate. Furthermore, the effect of pH and the molar ratio of MAP constituents on the removal of ammonium were evaluated. The maximum ammonium removal was observed as 98% at a pH of 8.5 and a stoichometric ratio of NH 4 /PO 4 /Mg = 1/1/1. The results obtained indicate that a combination of UASB and MAP can be successfully used for the removal of organics and ammonium from sanitary landfill leachate.