Nitrogen Removal from Landfill Leachate by Microalgae

• Published in: International journal of molecular sciences 2016-11, Vol.17 (11), p.1926-1926
• Main Authors: Pereira, Sérgio F L, Gonçalves, Ana L, Moreira, Francisca C, Silva, Tânia F C V, Vilar, Vítor J P, Pires, José C M
• Format: Article
• Language: English
• Subjects: Algae; Ammonia - isolation & purification; Biodegradation, Environmental; Biomass; Chlorella vulgaris; Chlorella vulgaris - growth & development; Chlorella vulgaris - metabolism; Kinetics; Leachates; Microalgae - growth & development; Microalgae - metabolism; Nitrates - isolation & purification; Nutrient removal; Waste Disposal Facilities; Water Pollutants, Chemical - isolation & purification; Water treatment
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms17111926

Landfill leachates result from the degradation of solid residues in sanitary landfills, thus presenting a high variability in terms of composition. Normally, these effluents are characterized by high ammoniacal-nitrogen (N-NH₄⁺) concentrations, high chemical oxygen demands and low phosphorus concentrations. The development of effective treatment strategies becomes difficult, posing a serious problem to the environment. Phycoremediation appears to be a suitable alternative for the treatment of landfill leachates. In this study, the potential of for biomass production and nutrients (mainly nitrogen and phosphorus) removal from different compositions of a landfill leachate was evaluated. Since microalgae also require phosphorus for their growth, different loads of this nutrient were evaluated, giving the following N:P ratios: 12:1, 23:1 and 35:1. The results have shown that was able to grow in the different leachate compositions assessed. However, microalgal growth was higher in the cultures presenting the lowest N-NH₄⁺ concentration. In terms of nutrients uptake, an effective removal of N-NH₄⁺ and phosphorus was observed in all the experiments, especially in those supplied with phosphorus. Nevertheless, N-NO₃ removal was considered almost negligible. These promising results constitute important findings in the development of a bioremediation technology for the treatment of landfill leachates.