Combined chemical, physical and biological treatment using Chlorella vulgaris sp. on landfill leachate

Abstract

Nowadays, the high amount of waste generated by the world population represents a major environmental problem. Landfills still represent one of the main endpoints of the solid wastes disposal in most of the countries. The major problem associated with this is the landfill leachate production. Leachate treatment using microalgae has been reported in numerous studies and it is a very promising method. A key challenge is the sensitivity of microalgae to high contaminants in landfill leachate. This paper underlines the landfill leachate treatment using Chlorella vulgaris sp. with pre-treated landfill leachate by physico-chemical treatment. Current research is to explore a dual purpose method to treat the leachate by incorporating Chlorella vulgaris sp. culturing in 100% pre-treated landfill leachate. During pre-treatment, the leachate samples were undergone coagulation process by using aluminium ammonium sulphate 12-hydrate followed by modified filtration system. The chemical analysis such as Total Solids (TS), turbidity, pH, Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total Organic Carbon (TOC), and heavy metal contents were analysed for landfill leachate samples before the treatment, after physico-chemical treatment, and after the combined physico-chemical-biological treatment using Chlorella vulgaris. The combined coagulation, filtration and microalgae treatments achieved removal efficiencies of more than 94% on turbidity, COD, BOD, TOC, and heavy metals. Effective contaminants removal efficiencies have been attained through the pre-treatment by coagulation and filtration. Microalgae managed to polish the pre-treated leachate to achieve the standard discharge limit according to DOE of Malaysia government. The lipids with broad carbon range of (C-21 to C-36) were identified in Chlorella vulgaris. The paper proves that the deteriorative impact of landfill leachate can be reduced successfully with combined treatment approaches.