Browsing by Author "Beyenal, Haluk"

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Combinatıon Of Electrochemical Oxidatıon And Bioelectrochemical Process To Treat Wastewater
(İksad Global, 2020) Öksüz, Seçil Tutar; Beyenal, Haluk
The electrochemical oxidation process is an environmentally friendly promising treatment option with different advantages to treat wastewater. The application of electrochemical oxidation processes to pollutants has attracted attention because it offers various advantages over other conventional treatment systems. For example, electrochemical oxidation processes don’t require high temperature and pressure as well as limited land requirements and no need for chemical addition, which can reduce carbon footprint. Electrochemical oxidation, however, requires a high operating cost due to the high-energy consumption for the wastewater treatment, limiting field application thus far. One of the potential solutions to reduce high costs is combining of electrochemical oxidation process with biological treatment, reducing operating cost and treatment time. Hybrid processes, such as the case of the electrochemical oxidation process and biological processing, can be combined through sequencing the electrochemical oxidation process as pre-treatment or as post-treatment depending on the characteristic of the used wastewater. In this study, we combined two promising technologies and aimed to treat wastewater with a bioelectrochemical system (partial), then treat it electrochemically with an electrochemical oxidation process (as a posttreatment) to efficiently remove chemical oxygen demand and nitrogen simultaneously, and so the treatment time and cost can be less than other systems. Hence, the goal was to treat wastewater faster in a smaller space with a coupled electrochemical oxidation process and bioelectrochemical system. First, the anodic biofilms were enriched on electrodes with a projected surface area of 0.95 cm2 . In the bioelectrochemical reactor, we treated wastewater by a polarizing working electrode at 0 VAg/AgCl in 3-electrode electrochemical cell. Then, we treated partially treated wastewater electrochemically by applying 10 VAg/AgCl. We compared the wastewater treatment efficiency in only bioelectrochemical system, only the electrochemical oxidation process, and electrochemical oxidation process as post-treatment after the bioelectrochemical system. Our results demonstrated that the coupled treatment increased ammonia and chemical oxygen demand removal rates compared to using only a single treatment method.
Citation - WoS: 9
Enhanced Bioelectrochemical Nitrogen Removal in Flow Through Electrodes
(ELSEVIER, 2021) Tutar Öksüz, Seçil; Beyenal, Haluk
In the past decade, bioelectrochemical systems (BESs) have been studied extensively for the generation of power and maximizing power densities. In recent years, it was noticed that BESs applications can critically improve wastewater treatment. Most of the previous BESs work has used varied reactor geometry and configuration, wastewater composition, electrolyte solution, and constant electrode size to maximize power generation. However, there is limited research investigating the influence of increased electrode size on the wastewater treatment process. We investigated the effect of increased electrode surface area on wastewater treatment effi-ciency and studied the mechanism of nitrogen removal. In this study, we developed a flow-through electrode in a 3-electrode bioelectrochemical reactor. The anodic biofilms were enriched on electrodes for one week. Following the anodic enrichment period, the reactor was operated in a semi-continuous mode with raw domestic waste-water. To investigate the wastewater treatment efficiency, the chemical oxygen demand (COD), total nitrogen (TN), ammonia (NH3-N), nitrite (NO2-N), and nitrate (NO3-N) concentrations were measured. We found that increased surface area of anode did not significantly contribute to COD removal rate, most likely indicating the limits of BES. On the other hand, the TN removal rate increased proportionally to the surface area of the anode in the BES. We also found that outlet NO3-N and NO2-N concentrations were 1.2 +/- 0.2 and 3.2 +/- 0.9 mg/L, respectively. Our results indicated that it is possible to remove COD and TN simultaneously. Analysis of the microbial community structure showed that nitrogen removal was dominated by sulfidogenesis, anodic ammonia oxidation, autotrophic and heterotrophic denitrification as well as reducing NO3-N to NO2-N using Geo-bacter species in our system.