Nitrogen Removal from Landfill Leachate by Microalgae

Abstract

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 Chlorella vulgaris 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 C. vulgaris 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.

A Review of Landfill Leachate Treatment by Microalgae: Current Status and Future Directions

“…SW15aRL showed significant TAN removal of~90% by day 30. Pereira et al (2016) [29] studied the growth of C. vulgaris in three different assays of pre-treated landfill leachate samples collected at the exit of an aerated stabilization pond. The microalgal growth was compared to three different N:P ratio (12:1, 23:1, and 35:1) obtained by externally adding KH 2 PO 4 ; also, a comparison was made for the case when no external P was added.…”

Optimization conditions for native microalgal strains grown on high ammonia-containing wastewater and their biomass utilization

“…In the attempt to find a successful algal strain for high ammonia tolerance there are currently several species under consideration around the world (Grzebyk et al 1998;Indarti et al 2015;Udom et al 2013;Zhang et al 2013;Abdelaziz et al 2014;Drira et al 2016;Passos et al 2016;Ruiz-Martinez et al 2012;Canedo-López et al 2016;Dahmani et al 2016;Franchino et al 2016;Kumari et al 2016;Montemezzani et al 2016;Pereira et al 2016).The selected strains are inoculated onto a polystyrene sterile nonpyrogenic 24-well flat bottom culture cluster containing synthetic wastewater. The synthetic wastewater may be a modification of BG11 media obtained by adding a different concentration of NH 4 Cl.…”

Outdoor Cultivation of the Microalga Chlorella vulgaris in a New Photobioreactor Configuration: The Effect of Ultraviolet and Visible Radiation

“…Microalgal cultures have been recently studied for environmental applications, such as CO 2 capture, wastewater treatment, among others [1][2][3]. Their use at the industrial level is still not economically viable due to high operational costs.…”

“…Besides carbon, nitrogen, and phosphorus are essential macronutrients for microalgal growth. These nutrients can be found in wastewaters of different sources [1,[7][8][9]. Using these effluents as microalgal cultures, the addition of fertilizers may be significantly reduced, and no freshwater is needed.…”