文档介绍：ARTICLE IN PRESS
WAT E R R E S E A R C H
41 (2007) 2220 - 2228
Available at
journal homepage: ate/watres
Comparison between alternating aerobic-anoxic and
conventional activated sludge systems
Saziye BalkuÃ
Atilim University Industrial Liaison Office, Ostim, 06370 Ankara, Turkey
a r t i c l e i n f o
Article history:
Received 25 September 2006
Received in revised form
17 January 2007
Accepted 28 January 2007
Available online 13 March 2007
Keywords:
Alternating aerobic-anoxic
Activated sludge
ASM3
Optimization
a b s t r a c t
Conventional activated sludge systems ensure removal of colloidal and dissolved anic matter whereas alternating aerobic-anoxic systems, in addition, satisfy a further reduction in nitrogen content of wastewater. Main difference between them is that the alternating system should also include an anoxic operation mode which satisfies denitrification. In other words conventional systems are operated under aerobic
conditions whereas alternating systems require a periodical change from aerobic conditions to anoxic conditions. So the most important problem in alternating systems is to find the appropriate durations for both sequences. In this study parison between conventional and alternating systems is considered in terms of nitrogen removal and aeration time by simulation under the same conditions together with an optimization algorithm. The results show that an activated sludge system can be operated as an alternating aerobic-anoxic system so that nitrogen removal is also possible during treatment without any additional investment or operational cost.
& 2007 Elsevier Ltd. All rights reserved.
1.
Introduction
Activated sludge process, one of the ways of biological
treatment, monly used in domestic wastewater treat-
ment, or in the secondary treatment of the industrial waste-
water. In conventional biological treatment systems colloidal
and dissolved anic matter removal are
aimed. If ni