Treating Urban Wastewater: Nutrient Removal by Using Immobilized Green Algae in Batch Cultures

Abstract

Essential roles of microalgae during the tertiary treatment of municipal wastewater have been proven. In order to avoid wash out of the biomass and also modify the quality of the treated wastewater; some techniques such as cell immobilization have been developed. To do so, in this study four samples from two species of microalgae (Chlorella vulgaris and Chlamydomonas sp.) were determined and confirmed by taxonomic identification. The samples were immobilized in calcium alginate beads. Within 10 days the amounts of nitrate (No3(-)-N) and orthophosphate (Po4(3-)-P) were measured to calculate the removal efficacy for each individual sample. Based on the standard methods, the amount of nitrate and orthophosphate were determined every 3 days within 10 days. The results indicate that immobilized microalgae are able to remove the nutrients and reduce the amount of nitrate and orthophosphate, significantly. Furthermore, the C. vulgaris (YG02) was the best species in this experience with 72% and 99% of reduction in the amount of nitrate and orthophosphate, respectively.

The impact of wastewater characteristics, algal species selection and immobilisation on simultaneous nitrogen and phosphorus removal

“…Comparing monocultures, some algal species are equally capable of removing N and P and of adapting to different wastewaters [27][28][29][30]. In other cases the proportion of N to P removed differs significantly between algal species treating a single wastewater [31][32][33], indicating appropriate species selection can promote nutrient removal. There are species dependent responses to environmental conditions [34; 35] which mean in an open system seasonal variations can cause fluctuations in the species present and remediation rates [36].…”

Nutrient Removal Efficiencies of <i>Chlorella vulgaris</i> from Urban Wastewater for Reduced Eutrophication

“…The presence of various forms of nitrogen and phosphorous in wastewater leads to eutrophication [38]. C. vulgaris has a high potential to reduce nutrients in secondary waste water treatment plants effluents [39] [40] [41] while simultaneously producing algal biomass with sufficient lipids content and an acceptable fatty acids profile for use as a biodiesel feedstock [42].…”

Optimization of Culture Conditions for Growth of Marine Phytoplankton

“…Many recent studies have reported the advantages of plankton culture under controlled conditions for attaining greater quality and quantity of biomass at lesser duration. Phytoplankton are potentially important for environmental impact assessment studies, synthesis of bioactive compounds, pigments, biofuels and applications in phytoremediation of contaminated wa-ter [3][4][5][6][7][8]. Most of the phytoplankton are sensitive to the ambient environmental conditions hence their community structure and biodiversity depends on ambient levels of nutrients, temperature, salinity, pH and light [9].…”