Removal of Organic and Nitrogen Compounds from Domestic Landfill Leachate by Microalgae

Water pollution by leachate has been widely reported in many regions in Indonesia. Landfill leachate contains high concentrations of organic and nitrogen, suitable for microalgae growth. Microalgae utilization for leachate treatment can be a promising alternative because it can simultaneously reduce pollutants and produce biomass. This study was conducted to identify microalgae that can grow well in leachate and examine mixed microalgae cultures' ability to reduce leachate pollutants. Microalgae obtained from a leachate treatment plant in Blang Bintang, Aceh Besar, were grown in a laboratory-scale photobioreactor. Microalgae identification was carried out morphologically using a microscope, while its performance in reducing pollutants was observed by COD, BOD, nitrate, and nitrite. The results showed that six microalgae species reduced leachate pollutants, namely Synedra acus, Spirulina sp., Euglena sp., Trichocerca sp., Paramecium sp., and Closteriopsis longissima, with Euglena sp. (40.63%) as the most abundant. The performance of mixed culture microalgae in this study showed promising results. COD, BOD, nitrate, and nitrite removal of 76.26%, 75.48%, 74.86%, and 73.52%, respectively, was observed during the experiment. As microalgae can grow well in leachate, in addition to reducing pollutants, such a treatment system can be integrated to produce biofuels and other bioproducts from microalgae biomass.