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Article Citation - WoS: 31Citation - Scopus: 35Comparison Between Alternating Aerobic-Anoxic and Conventional Activated Sludge Systems(Pergamon-elsevier Science Ltd, 2007) Balku, SaziyeConventional activated sludge systems ensure removal of colloidal and dissolved carbonaceous organic 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 a comparison 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. (C) 2007 Elsevier Ltd. All rights reserved.Article Citation - WoS: 4Citation - Scopus: 4Heavy Metal Inhibition on an Alternating Activated Sludge System and Its Comparison To Conventional Methods: Case Study of Cu2+(Iwa Publishing, 2021) Buaisha, Magdi; Balku, Saziye; Ozalp-Yaman, SenizIn order to understand the behaviour of wastewater treatment plants (WWTPs) with heavy metal presence, the present study evaluates the treatment process in the presence of heavy metals (Cu2+ as a case study) and compares it with the absence of heavy metals. An activated sludge model is improved by means of incorporating other novel inhibitory kinetic and settler models for this evaluation. To achieve this goal, a simulation algorithm is developed using the MATLAB code to detect any heavy metal influence on the aerobic and anoxic growth of heterotrophic and autotrophic biomass. The code also allows for a comparison of treatment plant performance with and without Cu2+ in both conventional and alternating systems. The results reveal that the presence of heavy metals, in case of the present study for Cu2+ at 0.5 mg/L, in a biological treatment system, has an inhibitory effect on the heterotrophic bacteria but more so on the autotrophic bacteria growth and it prevents nitrification and denitrification, thus negatively effecting on the nitrogen removal in the alternating systems.Article Citation - WoS: 15Citation - Scopus: 18Control Vector Parameterization Approach in Optimization of Alternating Aerobic-Anoxic Systems(Wiley, 2009) Balku, Saziye; Yuceer, Mehmet; Berber, RidvanDetermination of the optimal aeration profile for an activated sludge system in which nitrification and denitrification take place sequentially in a single reactor (alternating aerobic-anoxic) is an attractive optimization problem because of complexities involved in, and high computational times required for solution. The rigorous dynamic modeling and start-up simulation of such a system, together with aeration profile optimization by an evolutionary algorithm (EA), were tackled in a previous study. In this paper an easy-to-implement dynamic optimization technique based on sequential quadratic programming method and control vector parameterization approach is provided. In comparison with EA, the proposed algorithm gives better results in shorter computation times. Copyright (C) 2009 John Wiley & Sons, Ltd.Article Citation - WoS: 168Citation - Scopus: 186Heavy Metal Removal Investigation in Conventional Activated Sludge Systems(C Ej Publishing Group, 2020) Buaisha, Magdi; Balku, Saziye; Ozalp-Yaman, SenizThe combination of industrial and domestic wastewater in municipal WWTPs (waste water treatment plants) may be economically profitable, but it increases the difficulty of treatment, and also has some detrimental effects on the biomass and causes a low-quality final effluent. The present study evaluates the treatment process both in the presence and absence of heavy metals using ASM3 (activated sludge model no.3) so as to improve the model by means of incorporating other novel inhibitory kinetic and settler models. The results reveal that the presence of heavy metal, a case study for copper and cadmium at a concentration of 0.7 mgL(-1) in a biological treatment system has a negative effect on heterotrophic bacteria concentration by 25.00 %, and 8.76 % respectively. Meanwhile, there are no important changes in COD (chemical oxygen demand), SS (total suspended solids) and TN (total nitrogen) in the final effluent in the conventional system. However, all these parameters are acceptable and consistent with EU Commission Directives. The results indicate that ASM3 can predict and provide an opportunity of the operation for an activated sludge wastewater treatment plant that receives the effluent from an industrial plant.
