Effect of biyogas sparging and module geometric shapes on membrane fouling in anaerobic submerged membrane biyoreactors

The main problem in anaerobic membrane biyoreactors (AnMBRs) is membrane fouling, is a result of organic substances, settling of inorganic substances and adhesion of microbial cells on membrane surface. Researches are made on several factors such as sludge property, flux, cross-over flow velocity, back washing, module development and membrane material on control of membrane fouling. However, studies on membrane surface recirculation of biyogas that occurs in anaerobic systems and related to effects on membrane fouling are very limited. In anaerobic submerged membrane process, a study is not found that is related to monitoring of membrane fouling by membrane modules which formed different geometrical shapes that made of the same material.Modules which are made in different forms into a reactor that maintains stabile state of several parameters, settling two different group states, had be operated with gas recircu-lation in a part of system and in other part without gas recirculation. The cake layer for-mation, deposition of organic and inorganic substances formed on membrane surface were researched, making membrane autopsy by Scaning Electron Microscopy (SEM), chemical component on membrane surface by Energy Diffuse X-Ray(EDX), particulate Size Distri-bution (PSD), extraction of Hücre dışı Polimeric Subtances (EPS) and chemical analysis and analysis of Soluable Microbial Products (SMP).By monitoring fouling, a module form that provides the best membrane surface and gases contact was founded. This study is pro-cessed by using synthetic wastewater in laboratory and mesoflic (37oC) conductions.In this thesis, Specific objectives were to study the feasibility of using submerged AnMBRs for syentetic treatment, to quantify the chemical oxygen demand (COD) removal efficiency and biyogas production and composition to characterize sludge properties, in-cluding particle size, hücre dışı polymeric substances (EPS), soluable microbial products (SMP) and relations between membran module geometric forms and biyogas sparging on membrane fouling.During reactors operation, %95-98 of COD removed efficient, %38-65 of SO4=removed efficient, %96-98 of TOC removed efficient were founded. Also, efficienty of TVSS removed were founded over %97-98. Results show that the application of anaerobic membrane biyoreactors is an efficient way to retain specific bacteria that can be key for the treatment of wastewaters under extreme conditions. Applied biyokütle concentrations during AnMBRs operation were in the range 0,9-8 g/L. A great rate of TSS were founded to formation disolved solid. Under all conditions tested, cake formation showed to be the limiting factor determining the applicable flux. Low levels of irreversible fouling were observed, The latter is of great importance for the long term operation of the AnMBRs.A high COD removal efficiency was achieved, and the resulting biyogas was, again, of high fuel quality and a higher membrane fouling rate was present, and was related to the presence of a larger portion of fine colloidal particles. The experimental results from this study indicate that anaerobic treatment of wastewater under mesophilic conditions for energy recovery and for subsequent reuse of high quality permeates is feasible in terms of COD removal and biyogas production. However, membrane fouling caused by the large portion of fine particles may be a challenge.The permeate was of high quality, and the resulting biyogas, composed of %75-80 methane, was of excellent fuel quality. It was found that the bubbling of recycled biyogas was effective for in-situ membrane cleaning, depending on the recycle flow rate of produced biyogas. resulted in deflocculation, which led to an increase in membrane filtration resistance caused by fine flocs.Sludge properties, including SMP, bound EPS, and floc size, are the important parameters in governing sludge cake formation and membrane fouling in SAnMBR systems. Howover, membran fouling become to great rate causes of fine particulates can be a important issue. The development of a fraction of small particles, most likely originated from cells decay, produced an important influence on the filtration performance. Deflocculation which led to an increase in membrane filtration resistance caused by Fine floc or small particles. Eexposure of the sludge to a high shear stress affected sludge properties, reducing the attainable flux, most likely due to a reduction in particle size.Information that can be obtained from this thesis may be cause a lot of unclear point about AnMBRs will be revealed and also support to international science. Also the result of the assessment of applicable of gases sparging process will provide significantly information about using this process practically.The challenge for future research is finding the optimum operational conditions to control the cake layer formation, enhancing membrane performance and reducing the membrane area requirements. This will increase the economic feasibility of AnMBRs, enabling its full scale application.Keywords: Anaerobic Submerged Membrane Biyoreactor, Membrane Fouling, Biyogas Sparging, Membrane Moduls, SMP, EPS, PSD, Membrane Otopsisy, Fouling Resistances