بررسی کارایی سیستم لجن فعال هوادهی گسترده با سیکل متناوب (ICEAS) در حذف همزمان نیتروژن و فسفر از فاضلاب بیمارستانی

Abstract Introduction: Hospital wastewater including nutrients, nitrogen and phosphorous especially, that with discharge in environment result in problems in water ecosystem, animals and human health. Therefore, the aim of this study is determination of Nitrogen and phosphorous simultaneous removal from hospital wastewater by intermittent cycle extended aeration system (ICEAS). Methods: In this descriptive – sectional study, at the first was designed a Plexiglas column. Then, after microorganism's adaption period and start of loading principle stages, 180 samples collected from wastewater of mixing without aeration stage, influent and effluent from system. TN, TKN, NH4-N, organic-N, NO2-, NO3-, TP parameters were measurement according to standard methods. Finally, data analyzed by Design Expert software. Results: According to experiments, removal efficiency of TP, organic-N, NH4-N, TKN and TN was obtained %26-%90, %16-%95.3, %27-%94.6, %30-%95 and %17.5- %90, respectively. Effluent nitrite and nitrate concentration were 0.36-3.16 mg/l and 1.24-6.3 mg/l, respectively. Maximum of removal efficiency noted parameters achieved in maximum HRT (6hr) and MLSS (6000 mg/l). Conclusion: ICEAS system isn’t special process for nitrogen and phosphorous removal but in suitable condition of operation can remove above parameters with high efficiency. This system can be used in real scale.