Environmental Engineering,
A. Es,Hagi; H. Hazrati
Abstract
The membrane bioreactor (MBR) is a combination of biological and membrane systems. It utilizes advanced technologies in the treatment of various types of wastewater, having unique advantages such as the high-quality effluent and improved efficiency. The primary limiting factor for the utilization of ...
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The membrane bioreactor (MBR) is a combination of biological and membrane systems. It utilizes advanced technologies in the treatment of various types of wastewater, having unique advantages such as the high-quality effluent and improved efficiency. The primary limiting factor for the utilization of this bioreactor is the membrane fouling phenomenon, which increases operational costs. In this study, four membrane bioreactors were used, with the first MBR (R1) serving as the control bioreactor. In the second MBR (R2), an adsorption process was employed, while in the third (R3) and fourth MBR (R4), in addition to the adsorption process, the electrochemical process was applied with voltages of two and one volts respectively. For the four bioreactors, the percentages of the Chemical Oxygen Demand (COD) were recorded as 86%, 91.2%, 90.7%, and 95.3% respectively. The levels of the total Extracellular Polymeric Substances (EPS) in R1, R2, R3, and R4 were about 260, 155, 177, and 98 mg/gVSS respectively. The R4 exhibited significantly lower EPS (98 mg/gVSS) compared to R1 (260 mg/gVSS), possibly due to the adsorption of EPS by nanoparticles and its subsequent removal during the electrochemical process. The role of voltage was evident in R3, where the higher voltage (2V) resulted in the less removal of EPS (155 mg/gVSS) compared to the same in R4 (98 mg/gVSS). The study found that the values of the Soluble Microbial Products (SMP) for R4, R3, R2, and R1 were about 15, 65, 55 and 139 mg/L respectively. Particularly in the most effective MBR, R4, where the addition of the zeolite adsorbent alongside metal ions demonstrated the best performance in the removal of SMP.
M. Zangouie; A. Hemmati; M. Kian; J. Shayegan
Abstract
The membrane bioreactor (MBR) is a treatment bioreactor of urban and industrial wastewaters. The advantages of the MBR technology encompass high-quality effluents, less space requirements, and high-speed startups. This study aims to investigate the fouling phenomenon in the flour industry sewage ...
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The membrane bioreactor (MBR) is a treatment bioreactor of urban and industrial wastewaters. The advantages of the MBR technology encompass high-quality effluents, less space requirements, and high-speed startups. This study aims to investigate the fouling phenomenon in the flour industry sewage treatment. The pilot has been designed and constructed in line with the research concerning the industrial wastewater treatment. After the adaptation of microorganisms, physical and chemical tests such as chemical oxygen demands (COD), turbidity and total suspended solids (TSS), extracellular polymeric substances (EPS), and soluble microbial products (SMP) were conducted during the process. The concentration of mixed liquor suspended solids (MLSS) in the membrane bioreactor ranged between 5000 and 8500 mg/L. Hydraulic retention times (HRTs) were fixed at 4, 8, and 16 h. Three types of resistance were considered via measuring the leakage current and transmembrane pressure (TMP). Accordingly, the total resistance rates for HRTs of 4, 8, and 16h were 22.5×1010, 21.3×1010, and 20.4×1010 m-1 respectively. Considering the average organic loading rate (OLR) in three HRTs of 4, 8, and 16 h (8.84, 5.13, and 2.84 kg the COD/m3×day respectively), the daily feed was provided to the bioreactor, and the removal efficiency of COD was assessed. An average removal of 95 % was achieved in the whole process. In this method, the input turbidity of the effluent has been increased to 187 NTU and, then, reduced to less than 3 NTU. It was also observed that EPS, SMP, and the extracted carbohydrates played more vital roles in the membrane biofouling than the extracted proteins.