Biomass Separation in Moving Bed Biofilm Reactors with Innovative Filters

Document Type : Research Article

Authors

1 Chemical and Petroleum Engineering Department, Sharif University of Technology, Tehran, I.R. IRAN

2 Chemical and Petroleum Engineering Department, Biochemical and Bioenvironmental Engineering Research Center (B.B.R.C), Sharif University of Technology, Tehran, I.R. IRAN

Abstract

Membrane bioreactors (MBR Process) are now considered as one of the main new processes in wastewater treatment. Membranes used for wastewater purification are fabricated from different oil based polymers includingPVC, polysulphonates, polyamides and many other synthetic polymers. Fabrication technology is advanced and only in possession of very few multinational companies. For these reasons, membranes are expensive and not easily available. This study was carried out to test an innovative, locally made filter element for separation of flocks in an MBBR reactor. This innovative filter is seen as a viable replacement to a conventional settling tank that may be even as effective as synthetic polymer membranes. The filter’s element was made very cheaply and had important advantages in installing and operation. Experiments were carried out using a laboratory scale MBBR unit as the biological aerated reactor, fixed with filter elements inside aeration chamber, similar to a MBR installation. The filter elements consisted of 3 plastic filter tubes with perforations and covered with dense cotton-polyester yarns and were placed inside the aeration chamber. The bioreactor was run over a period of 10 months with usual conditions resembling a real biological wastewater treatment unit.  Reactor performance was measured regularly and the results indicated that 99% of suspended solids are separated under normal conditions. Filter clogging, a very familiar problem with membrane bioreactors, was not seen as an obstacle in bioreactor operation. Outflow TSS was lower than 12 mg/L, while overall organic removal was over 95 percent. Next set of experiments were carried with fewer filter elements and higher value of TSS in the effluent was observed, indicating that filters surface area (or number of filter elements) have a profound effect on treatment efficiency as could be well expected. Overall the experiments indicated that locally made MBR can easily be applied in existing plants, saving money and operational difficulties.  

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[1] Metcalf, Eddy, Inc., "Wastewater Engineering Treatment, Disposal, Reuse", 3rd ed, McGraw-Hill (1991).
[2] Bernard J.Dutka., "Membrane Filtration, Applications, Techniques, and Problems", ISBN: 0-8247-1164-5, (1981).
[3] آیتی ، ب ، دلنواز ، م ، گنجی دوست، ح .، سینتیک واکنش تصفیه فاضلاب حاوی آنیلین در راکتور بیو فیلمی با بستر متحرک" مجله سلامت و محیط ، فصلنامه علمی پژوهشی انجمن علمی بهداشت محیط ایران، (1)2، ص. 76 (1388).
[4] Satywali Y., Balakrishnan M., Treatment of Distillery Effluent in a Membrane Bioreactor (MBR) Equipped with Mesh Filter, Separation and purification Technology, 63, p. 278 (2008).
[5] Chang I.S., Lee C.H., Membrane Filtration Characteristics in Membrane Coupled Activated Sludge System - The Effects of Physiological States of Activated Sludge on Membrane Fouling, Desalination, 120, p. 221 (1998).
[6] In - Soung Chang., Su - Na Kim., Wastewater Treatment Using Membrane Filtration - Effect of Bio solids Concentration on Cake Resistance, Process Biochemistry, 40, p. 1307 (2005).
[7] Kuo-Jen Hwang., Chih-Sheng Chan., Kuo-Lun Tung., Effect of Backwash on the Performance of Submerged Membrane Filtration, Journal of Membrane Science, 330, p. 349 (2009).
[8] Le-Clech P., Chen V., Tnony A.G.Fane., Fouling in Membrane Bioreactors Used in Wastewater Treatment, Journal of Membrane Science, 284, p. 17 (2006). 
[9] Borghei, S.M., Hosseini, S.H., The Treatment of Phenolic Wastewater a Moving Bed Reactor, process Biochemistry, 39, p. 1171 (2004).
[10] حسنیه فولادی قلعه ، بررسی کارایی بیوراکتور غشایی غوطه ور در حذف مقادیر کم ترکیبات آلوده کننده مقاوم (سموم و آفت کش) ، پایان نامه کارشناسی ارشد ، گروه محیط زیست ، دانشکده مهندسی شیمی و نفت ، دانشگاه صنعتی شریف ، سال 1388
[11] APHA, AWWA and WPCF ., "Standard Method for the Examination Water and Waste water", 19th Edition, Washington, USA. (1995).