Nitrogen Removal from Landfill Leachate via ex-situ Nitrification and in-situ Denitrification in Laboratory Scale Bioreactor

Indonesia is a one of the emerging market economies of the world, the country not only faces increasing GDP, but also generation of solid waste. Around 16.7 tons per year of solid waste are generated which consists of around 65% organic and 35% inorganic materials, and most of the waste is disposed of in 500 landfills. Almost all of these landfills are open dumps and have no wastewater treatment for their leachate. Over the period, nitrogen from leachate is treated mostly by ex-situ nitrification-denitrification which is expensive and requires a large area. This study aims to develop landfill as a bioreactor in in-situ denitrification after ex-situ nitrification. Two columns of bioreactor landfill in a laboratory scale were used: R2 reactor with 2 year-old waste and R4 reactor filled with a 4 year-old waste. Results showed that both bioreactors are able to achieve nitrate removal through in-situ denitrification, Based on the first order reaction, R2 has higher nitrate removal rate of 0.0302 mg/L/hour compared to 0.0226 mg/L/hour of R4. No significant difference in nitrate removal ability on each samplings ports with different heights on both reactors. This may be caused by the even distribution composition of waste and leachate on both bioreactors.