Treatment of sewage and industrial wastewater effluents by the cyanobacteria Nostoc muscorum and Anabaena subcylinderica

Abstract

The potential of two cyanobacteria, Nostoc muscorum and Anabaena subcylindrica to treat sewage and industrial wastewater effluents was investigated. Two different sites were selected for this study which are located at the drains of sewage plant, a salt and soda production company at Kafr El-Zayat city. All samples were taken from the sewage and/or industrial effluents before treatment. Treatment of the sewage and industrial wastewater effluents by using cyanobacteria (N. muscorum, A. subcylindrica and mixed culture of both) revealed that the pH value of the biologically treated wastewater increased, the electrical conductivity was recovered in a range between (4.7–23.9%) and the total dissolved solids were reduced by (4.4–23.3%). The reduction of turbidity level was in a range between (40–96.4%). The removal efficiency of organic matter (COD, PV) was in a range between (20–57.1%) and (25.7–66.7%), respectively. Phosphorus reduction, nitrate treatment and ammonia elimination efficiencies by cyanobacterial system were (20.8–95%), (19.6–80%) and (20.9–96%), respectively. With respect to the treatment efficiency of wastewater by using single or mixed cultures of cyanobacteria, it was observed that the single cultures in most cases was better than the mixed cultures and this may be due to the competition between mixed cultures for nutrients. However, it could be concluded from the presented data that the treatment of wastewater by cyanobacteria is a fruitful method to produce an effluent of high quality to be used for irrigation.