Ammonia-nitrogen and phosphate removal in leachate using algae and bacteria mixture

Abstract

Leachate is a liquid that has been produced by the waste especially organic waste. In an engineered sanitary landfill, biological treatment is a common practice to reduce the leachate contaminants. The effluent from treated leachate needs to comply with the standard set by the Department of Environment (DOE), Malaysia before it is being released into the river. The leachate contains a high number of contaminants such as ammonia-nitrogen, phosphorus, heavy metal, biochemical oxygen demand (BOD), chemical oxygen demand (COD) and suspended solids. This study focused on the possibility of treating leachate by using algae and bacteria in biological treatment in removing ammonia-nitrogen and phosphate in leachate obtained from Air Hitam Sanitary Landfill, Puchong. Initially, the characteristics of the leachate sample with in-situ and laboratory tests were analyzed to quantify the contaminants in the leachate. In this research, the concentration of leachate samples together with algae and bacteria was diluted in one (1) liter of distilled water varied between 10%, 30%, 50%, 80% and 100% (v/v) in each flask. Then, all the samples were aerated to ensure that the algae and bacteria were at the optimum condition to treat the contaminants in the leachate for all the respective flasks. The results of ammonia-nitrogen, phosphate, nitrite-nitrogen, and nitrate-nitrogen were taken for every 3 days for 15 days to determine the percentage of the removal due to the algae and bacteria uptake in the leachate for all the samples. After 15 days, the percentage of removal of the contaminants were analyzed using factorial design. It showed that 50% (v/v) of leachate concentration in the diluted flask exhibits the highest removal percentage of ammonia-nitrogen with 96.95% ammonia-nitrogen being removed from the leachate. For phosphorus, 10% (v/v) diluted leachate concentration marked highest which is 94.92% has been removed from the leachate. Finally, the regression equation was established to predict the rate of ammonia-nitrogen removal.