نوع مقاله : مقاله پژوهشی
1 دانشجوی کارشناسی ارشد علوم محیط زیست، دانشکده محیط زیست و انرژی، واحد علوم و تحقیقات دانشگاه آزاد اسلامی
2 استادیار دانشکده منابع طبیعی، دانشگاه تهران
3 استادیار دانشکده محیط زیست و انرژی، واحد علوم و تحقیقات دانشگاه آزاد اسلامی
عنوان مقاله [English]
Zebra mussel (Dreissenidae polymorpha) is capable of filtering great volumes of water due to its high population density. In this study, Nitrate and Phosphate removal capability of 3 shell masses (20, 40, and 60 gr) in urban wastewater was investigated based on filtering rate measurements (using simultaneous phytoplankton, chlorella, and Scenedesmus cultures) and indirect absorption of nitrate and phosphate in open and closed systems with 3 to 10 replications. Open and closed systems showed a positive correlation between shell weights and Nitrate and Phosphate filtration rates (R2 =0.99) but a negative correlation between influent Nitrate and Phosphate concentrations and their filtration rates (R2=0.97). Increasing of shell weights in the open system resulted in absorption rates of 0.08-0.2mg.l-1 of the shell dry weight for Nitrate and 0.02-0.04 mg.l-1 for Phosphate. In the closed system, these rates were 0.03-0.11 mg.l-1 of the shell dry weight for Nitrate absorption and 0.01-0.02 mg.l-1 for Phosphate. These results show that shell masses have a low nitrate and phosphate removal efficiency, especially in the case of phosphate, and they can not be, therefore, recommended for urban wastewater treatment.