English

Abstract

 Abstract— Our nature and natural resources are the real teachers of our engineers. In wastewater engineering, one of the most sophisticated methods of wastewater treatment is the tertiary treatment or biological treatment. Methods such as biodisc, biofiltration and activated sludge use tiny organisms to remove organic and inorganic pollutants from wastewater. Other higher levels of organisms, such as plants, have been also used for polluted water purification. In phytoremediation, with its different methods of purification, plants are used to remove pollutants from wastewater. Other organisms such as algae, shellfish and fish can be also applied for wastewater treatment. In this paper, the results of the research on using organisms to remove pollutants such as heavy metals from different kinds of wastewaters are presented. The researches were either based on the measurements on nature, or pilot studies in the laboratory. We used water hyacinth to remove nitrate, phosphate, BOD5 and COD from municipal wastewater. The common reed and some other aquatic plants were used for the purification of wastewaters discharged from oil industries and gas purification factories. The concentrations of metals were measured in tissues of organisms exposed to polluted waters in nature; organisms such as algae, fish, shellfish, plants and worms. High concentrations of metals were observed in the organism tissues, suggesting they are favorable for wastewater treatment. The results suggest that a combination of methods would be the most appropriate and in most cases economic method for the treatment of different types of wastewater.