Using Microalgae for Nitrate-nitrogen and Orthophosphate Removal from Municipal Wastewater

To avoid water and environmental pollution, the wastewater should be treated and reused. Novel methods of water and wastewater treatment are offered in environmental biotechnology using single cell organisms like micro algae. Since the removal of any contaminant is harmonized to its sanitary and environmental significance, nutrients removal has a specific concern due to emerge of eutriphication in water resources. The aim of this research is to study the behavior of micro algae in removal of nitrate- nitrogen and orthophosphate from municipal waste water. To find a strain which has a higher removal rate of NO3- -N and PO43- -P, 10 strain of micro algae were immobilized in sodium alginate gel and then inoculate in wastewater samples of Shiraz wastewater treatment plant for 12 days. The results show that Chlamydomonas sp. had removed 82.4% of nitrate- nitrogen and 71.9% of orthophosphate from wastewater and had the higher removal rate amongst other species. Likewise, Chlorella vulgaris had the highest oxygenation capacity. According to high growth rate and protein contents of micro algae, the biomass can be used in industries, agriculture, pharmaceutical and food industry.