Microalgae cultivation in stabilized landfill leachate for simultaneous treatment and biomass production

Background

The high toxicity of landfill leachate has motivated to an investigation of economical and ecological treatment prior releasing into environment. Recently, microalgae have emerged as an alternative method due to its ability to recover nutrient and potential for bio-fuel production. However, the high concentrations of inhibitory compounds and ammoniacal nitrogen in young landfill leachates require high dilutions for microalgae to thrive. Hence, this study aims to evaluate the performance of microalgae by using stabilized landfill leachate with lower to no dilutions in nutrient removal, biomass and lipid production.

Methods

Leachate concentrations of 33, 44, 66, 89 and 100 v/v% were initially treated with the microalgae C. vulgaris. Parameters of chemical oxygen demand (COD), ammoniacal nitrogen (NH₃–N), orthophosphate (PO₄³⁻), total phosphorus (TP) and colour removal were evaluated. Cost analysis was conducted to evaluate the economical appropriateness.

Significant findings

The highest removals were achieved at 43.67% of COD, >97% of NH₃–N, 79.26% of PO₄³⁻, 77.64% of TP and 44.04% of colour. Highest biomass yield obtained was 220 mg/L by 89 v/v% of leachate concentration with 8.14% of lipid yield. Cost of treatment was calculated to be ∼$0.02 per m³ leachate. The feasibility of stabilized landfill leachate treatment without any dilutions using microalgae was attained as they can survive amidst this condition, perform nutrient removals, and produce biomass simultaneously.