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008			011298s1985 th r 000| 0eng d
035			_a.b10151849
099		9	_aAIT Thesis no.EV-85-28
100	0		_aYossarin Bhimsakka
245	1	0	_aComparison of declining rate coarse media filtration with constant rate dual media filtration at Bangkhen water treatment plant
260			_aBangkok : _bAsian Institute of Technology, _c1985
300			_a115 p.
490	1		_aThesis ; _vno. EV-85-28
500			_aA thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development
502			_aThesis (M.Sc.) - Asian Institute of Technology, 1985
520			_aBangkhen Water Treatment Plant used dual media filter to remove the suspended solids from the effluent of solid-contact clarifier. The dual media filters used contains 80 cm of anthracite (E.S. = 0.85 mm; U = 1.5) over 40 cm of sand (E.S. + 0.5 mm, U = 1.5) at a filtration rate of 13.75 m3/m2.h. In this study the possibility of using narrowly graded sand as sole filter medium was investigated. The two sand sizes studied (1.00 to 1.19 mm; 1.19 to 1.41 mm and 1.20 m depth) indicated that the narrowly graded coarse medium produces comparable filter quality while leading to less headloss development. In this case the headloss was found to be more uniformly distributed especially when high filtration rates (>15 m3/m2.h) were used. The backwash velocity computation made for single coarse medium and dual media filters indicated that the former required much higher backwash rate than the latter for comparable degree of expansion. The declining rate filter experiments conducted with single medium filters indicated that the headloss development is lesser in the case of declining rate filtration compared to constant rate filtration for the same water production. This indicates the declining rate filtration can be operated for a longer time before backwashing which will reduce the significantly the operating cost of filter. The headloss equation H/Ho = 1+KO is found to be valid for constant rate filters and the value of K decreased with the increase in filtration rate and increase in sand size. The prediction of headloss for declining rate filters was satisfactory when using the K value of the average (both arithmetic and geometric means) velocity.
650		0	_aWater treatment plants _xThailand _xBangkok
650		0	_aFilters and filtration
700	1		_aVigneswaran, S., _eChairperson
700	0		_aSamorn Muttamara, _eExamination Committee
700	1		_aLohani, B.N., _eExamination Committee
710	2		_aFederal Republic of Germany (CDG), _eScholarship Donor
810	2		_aAsian Institute of Technology. _tThesis ; _vno. EV-85-28
856			_3Full-Text _uhttp://203.159.5.9/ait-thesis/detail.php?q=B20027
907			_a.b10151849 _bmnait _cx
902			_a240411
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962			_a000:001:PDF:b1015184:004658:0:0:0:0:0:0 _tAbstract _vn
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999			_c19896 _d19896