000			05065nas a2200421 i 4500
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008			170699s1991 th u m rtt 0| a1eng d
035			_a.b10183322
099		9	_aAIT Diss. no. EV-91-1
100	0		_aSompol Boonthanon
245	1	0	_aDe-clogging of CFMF membranes : _bapplication in water and wastewater treatment
260			_aBangkok : _bAsian Institute of Technology, _c1991
300			_a171 p.
490	1		_aDissertation ; _vno. EV-91-1
500			_aA dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Technical Science, School of Environment, Resources and Development
502			_aThesis (Ph.D.) - Asian Institute of Technology, 1991
520			_aCrossflow microfiltration (CFMF), technically being a very effective filtration process for separation of both colloidal and suspended particles from liquid, however, at this stage is found to be commercially viable mainly for obtaining high value products but not yet in water and wastewater application due to the high installation and operation costs. And further, the problems of f lux decline resulting from fouling, deposition and internal clogging of membrane etc., demand more research in an attempt to improve t he effectiveness of the process, especially in terms of flu x improvement techniques. In this present study, different sets of CFMF experiments were carried out to stud y the use of backflush as a de-clogging technique in enhancing the process performance. The membranes used in this study were bought from SCT1, France, but the membrane housing and t he whole experimental set up was designed and fabricated locally. Synthetic and natural suspensions were tried out. Backflush technique was found to improve the efficiency of the filtration process when synthetic suspensions of clay alone and clay together with colloids were used. The effect of backflush frequency, Tf, and backflush duration, Tb , were studied and it was observed that for CFMF with clay suspension Tf = 1 min., Tb= 1 sand with clay and colloids as suspension , Tf = 2 min. , Tb = 1 s were found to be the best operating conditions. The improvement in productivity, Ipv, of the stabilized productivity of the two experiments were 290% and 210%, respectively, compared to CFMF without backflush. In order to study the application of CFMF with backflush technique, natural water and filter backwash wastewater from water treatment plant were used. The best operating condition for these two suspensions were Tf = 5 min ., Tb= 5 sand Tf = 1 min., and Tb= 1 s respectively. The Ipy of the stabilized productivity were 220% and 1,300% respectively, compared to CFMF without backflush. Thus backflush technique can be effectively used as a de-clogging technique in CFMF for treating filter backwash wastewater. Both t he new and used membranes were chemically cleaned and further subjected to filterability test before using in the experiments. These two techniques, i .e ., chemical cleaning and filterability test were developed by the researcher. Other de-c logging technique, i.e., pulsation cleaning technique was also tried; but it was found to be less effective compared to backflush technique. Further, when other f lux improvement techniques like flocculation of suspension was investigated, it was observed that though this technique has promising effect in increasing t he performance , the effect of using flocculation coup led with backflush technique is even more significant, evidenced by t he I of t he stabilized productivity which is 1,010% compared to that with CFM~ without backflush and without flocculation. This tremendous improvement in CFMF performance can thus be said as a breakthrough in membrane technology.
650		0	_aSewage _xPurification _xFiltration
700	1		_aHarada, Hideki, _eChairperson
700	1		_aVigneswaran, Saravanamuthu, _eExamination Committee
700	1		_aAim, Roger Ben, _eExamination Committee
700	1		_aMora, Jean-Claude, _eExamination Committee
700	0		_aSamorn Muttamara, _eExamination Committee
810	2		_aAsian Institute of Technology. _tDissertation ; _vno. EV-91-1
856			_3Full-Text _uhttp://203.159.5.9/ait-thesis/detail.php?q=B17424
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