Performance of areation systems (activated sludge) with fixed bed for the treatment of wastewater with high organic load

Subject Areas : environmental management

Amir Hesam Hassani ¹ , Amir Hossein Javid ² , Ali Torabian ³ , Seyed Morteza Hosseinian ⁴ , Amir Hayatbakhsh ^{5 *}

1 - Faculty of Environment and Energy, Science and Research Branch, Islamic Azad University
2 - Faculty of Environment and Energy, Science and Research Branch, Islamic Azad University
3 - Faculty of Environment, University of Tehran
4 - کارشناس ارشد مهندسی شیمی، مهندسین مشاور فرپاک.
5 - Faculty of Environment and Energy, Science and Research Branch, Islamic Azad University

Received: 2006-02-01 Accepted : 2006-05-24 Published : 2009-12-22

Keywords: activated sludge, Fixed bed, wastewater with high organic l,

Abstract :

This study was conducted to review the performance of aeration systems (activated sludge) with fixed bed for the treatment of wastewater with high organic load through the use of down flow and up flow aerated reactors. To this end, a plaxy tank with three sections was used; the sections include the down flow aerated reactor, the up flow aerated reactor, and the gravity sedimentation unit. These aerated reactors are equipped with media made of PVC, CROSS FLOW, with a specific surface equal to 81.34 m2/m3. The performance of the system was reviewed through COD concentrations of 500, 1000 and 1500 mg/l and with organic loadings equal to 16.32, 33.36, 50.40, 34.56, 44.64, 101.52, 63.12, 125.28 and 188.40 gr COD/m2.d. At the end of the performance steps of this study, it is shown that (1) with organic loadings equal to 16.32, 33.36 and 50.40 gr COD/m2.d and COD concentrations equal to 500, 1000 and 1500 mg/l, the average quantity percentages of COD removal were equal to 96.11, 87.93 and 69.67 percent, (2) with organic loadings equal to 34.56, 44.64 and 101.52 gr COD/m2.d and COD concentrations equal to 500, 1000 and 1500 mg/l, the average quantity percentages of COD removal were equal to 93.67, 83.67 and 61.67 percent, and (3) with organic loadings equal to 63.12, 125.28 and 188.40 gr COD/m2.d and COD concentrations equal to 500, 1000 and 1500 mg/l, the average quantity percentages of COD removal were equal to 89.17, 77.33 and 52.83 percent. The results show that with organic loadings equal to 34.56, 44.64 and 101.52 gr COD/m2.d, the optimum quantities of COD are removed. With a concentration equal to 1500 mg/l and the COD removal equal to 52.83%, the system can be used effectively for the pretreatment of wastewater with a high organic load. Also the maximum organic loading for the system is determined with organic loading equal to 188.40 gr COD/m2.d and COD concentration equal to 1500 mg/l.