Browsing by Author "Özcan, Özlem"

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Development of hybrid membrane processes for energy and water recovery from municipal wastewaters
(Abdullah Gül Üniversitesi, Fen Bilimleri Enstitüsü, 2024) Özcan, Özlem; AGÜ, Fen Bilimleri Enstitüsü, Malzeme Bilimi ve Makine Mühendisliği Ana Bilim Dalı
This thesis study aims to develop a hybrid innovative membrane-based process that maximizes circular benefit with the recovery of energy, nutrients, and water from municipal wastewater (MWW). This process was designed to be a sustainable alternative to the widely used advanced biological wastewater treatment plants (WWTP). For this purpose, the wastewater samples from the pre-sedimentation tank effluent of the Kayseri WWTP were used in laboratory-scale membrane-based process applications. In the first stage of the study, pre-concentration studies were performed to concentrate the organic matter and nutrients in the wastewater using the chemically enhanced primary sedimentation+direct ceramic microfiltration (CEPS+DCMF) process. Wastewater concentrated up to 8 times in the CEPS+DCMF process was fed to the anaerobic fluidized bed ceramic membrane bioreactor (AnFCMBR), which is the second stage of the study. The performance of the reverse osmosis (RO) process was evaluated for nutrient recovery performance in permeates of AnFCMBR and CEPS+DCMF processes. Chemical precipitation was performed on RO concentrate samples to recover struvite. With the innovative membrane-based hybrid wastewater treatment process, a net energy recovery potential of 0.126 kWh/m3 was attained by operating the AnFCMBR process at 6 hours hydraulic retention time, while an energy requirement of 0.08 kWh/m3 was attained and thus, an energy-positive process for treating MWW has been developed.
Pre-concentration of Municipal Wastewater Using Flocculation-Assisted Direct Ceramic Microfiltration Process: Optimization of Operational Conditions
(SPRINGER INT PUBL AG, 2022) Ozcan, Ozlem; Sahinkaya, Erkan; Uzal, Nigmet; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Uzal, Niğmet; Özcan, Özlem
Direct ceramic microfiltration (DCMF) is an effective technology to pre-concentrate organic matter (OM) for the subsequent anaerobic energy-recovering processes and a fast, cost-effective, easy treatment process for municipal wastewater. The major problem in DCMF is the rapid fouling of the membrane. In this study, to maximize OM recovery rates and prevent membrane fouling, the DCMF process was alternately paired with dosing of a cationic polyacrylamide (PAM) flocculant and chemically enhanced primary sedimentation (CEPS). The DCMF process tested in three stages: (i) optimization of flocculant concentration (0.5, 1, 1.5, and 2 mg/L PAM) and dosing point, (ii) optimization of operational conditions (pH, filtration/backwash duration, flux, and recovery rate) to control membrane fouling, and (iii) long-term operation of the DCMF process. The influence of PAM dosage points on DCMF fouling behavior was explored, and system operating parameters in terms of OM recovery and TMP change were optimized. The CEPS + DCMF setup was discovered to be a potential option for overcoming fouling. The highest chemical oxygen demand (COD) was 520 +/- 20 mg/L in the concentrated wastewater using CEPS + DCMF experiments for 0.5 mg/L PAM. The highest OM pre-concentration was achieved at 90% recovery rate. After the optimization, COD concentration in the concentrate of the DCMF process reached 822 mg/L for the long-term (20 days) operation. The net potential energy production was calculated as 0.28 kWh/m(3) considering the theoretical COD of 1432 mg/L in the concentrate stream. As a novel approach, the CEPS + DCMF process can be used in place of conventional municipal wastewater treatment processes due to its acceptable OM removal performance, simple operation, small footprint, and potential energy generation.