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20:
75:
Rapid sand filters are typically designed as part of multi-stage treatment systems used by large municipalities. These systems are complex and expensive to operate and maintain, and therefore less suitable for small communities and developing nations. The filtration system requires a relatively small
218:
The byproduct of backwashing is sludge. Most treatment works use a sludge thickening process, except for plant which discharge untreated sludge to sewers if the composition is within the tolerable limits. The thickening process comprise batch settling tanks or continuous picket fence thickeners.
219:
Polyelectrolytes are added upstream to enhance settleability. Liquid from the process is routed to the inlet of the works. Thickening is followed by either lagooning, drying beds or filter pressing. Thickened sludge may be discharged to a sewer system, tankered away to landfill, or incinerator.
83:
Rapid sand filters use relatively coarse sand (0.5 to 1.0 mm) and other granular media, such as anthracite, in beds of 0.6 to 1.2 metre depth to remove particles and impurities that have been trapped in a
96:. Since media other than silica sand can be used in such filters, a more modern term is "rapid filtration" instead of "rapid sand filtration." The unfiltered water flows at about 5 m/h, through the
403:
E. Soyer, Ö. Akgiray, N. Ö. Eldem, A. M. Saatçı (2013). On the use of crushed recycled glass instead of silica sand in dual-media filters. Clean – Soil, Air, Water 41 (4), 325–33.
43:
facilities as part of a multiple-stage treatment system. These systems are complex and expensive to operate and maintain, and therefore less suitable for small communities and
55:
Rapid sand filters were first developed in the 1890s, and improved designs were developed by the 1920s. The first modern rapid sand filtration plant was designed and built by
522:
107:
processes are typical treatment stages that precede filtration. Chemical additives, such as coagulants, are often used in conjunction with the filtration system.
125:) is commonly used following filtration. Rapid sand filtration has very little effect on taste and smell and dissolved impurities of drinking water, unless
490:
63:. Rapid sand filters were widely used in large municipal water systems by the 1920s, because they required smaller land areas compared to
515:
388:
363:
299:
680:
104:
690:
458:
426:
379:
American Water Works
Association (1999). "Chapter 8. Granular Bed and Precoat Filtration". In Letterman, Raymond D. (ed.).
670:
508:
133:
110:
The two types of rapid sand filter are the gravity type (e.g. Paterson's filter) and pressure type (e.g. Candy's filter).
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land area in proportion to the population served, and the design is less sensitive to changes in raw water quality, e.g.
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under gravity or under pumped pressure and the floc material is trapped in the sand matrix.
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Technologies for
Upgrading Existing or Designing New Drinking Water Treatment Facilities
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317:"The Filtration Works of the East Jersey Water Company, at Little Falls, New Jersey"
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421:(3rd ed.). Denver, CO: American Water Works Association. 2003. p. 117.
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Rapid sand filters must be cleaned frequently, often several times a day, by
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350:
Water 4.0: The Past, Present, and Future of the World's Most Vital
Resource
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785:
760:
545:
404:
381:
Water
Quality and Treatment : A Handbook of Community Water Supplies
118:
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500:
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122:
18:
136:, which involves reversing the direction of the water and adding
93:
504:
294:. Denver, CO: American Water Works Association. pp. 1–2.
273:
482:
Handbook of Water and
Wastewater Treatment Plant Operations
321:
Transactions of the
American Society of Civil Engineers
453:. Oxford: Pergamon. pp. 374–375, 3811, 388, 389.
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814:
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144:and care must be taken not to wash away the media.
347:
354:. New Haven, CT: Yale University Press. pp.
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8:
277:(Report). Cincinnati, OH. EPA 625/4-89/023.
23:Cutaway view of a typical rapid sand filter
523:
509:
501:
147:The backwash sequence would typically be:
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16:Type of filter used in water purification
383:(5th ed.). New York: McGraw-Hill.
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405:https://doi.org/10.1002/clen.201100470
7:
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214:Open inlet valve when filter is full
129:is included in the filter medium.
39:and is commonly used in municipal
14:
140:. During backwashing, the bed is
704:
315:Fuller, George W. (June 1903).
449:Water Research Centre (1977).
1:
451:Water Purification in the EEC
211:Bring controller into service
202:Surface flush for 0-5 minutes
35:is a type of filter used in
479:Spellman, Frank R. (2008).
190:Wash water for 0-10 minutes
892:
741:Electrostatic precipitator
291:Water Filtration Practices
169:Air scour for 0-10 minutes
80:, than slow sand filters.
781:Rotary vacuum-drum filter
702:
288:Logsdon, Gary S. (2011).
199:Open surface flush inlet,
157:Allow water to drain down
103:Mixing, flocculation and
824:Aqueous two-phase system
646:Liquid–liquid extraction
184:Open upwash valve slowly
117:system (typically using
61:Little Falls, New Jersey
721:API oil–water separator
591:Dissolved air flotation
686:Solid-phase extraction
346:Sedlak, David (2014).
333:10.1061/TACEAT.0001566
249:Automated pool cleaner
24:
806:Vacuum ceramic filter
801:Sublimation apparatus
606:Electrochromatography
566:Cross-flow filtration
181:Start washwater pumps
22:
756:Fractionating column
551:Acid–base extraction
532:Separation processes
208:Lower washwater weir
196:Raise washwater weir
166:Open air inlet valve
92:chemicals—typically
71:Design and operation
33:rapid gravity filter
576:Cyclonic separation
205:Close washout valve
187:Open wash out valve
88:through the use of
636:Gravity separation
193:Close upwash valve
160:Close outlet valve
154:Isolate controller
45:developing nations
37:water purification
25:
858:
857:
776:Rapid sand filter
671:Recrystallization
651:Electroextraction
611:Electrofiltration
492:978-1-4200-7530-4
151:Close inlet valve
65:slow sand filters
29:rapid sand filter
883:
876:Water technology
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335:. Paper No. 954.
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278:
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244:Trickling filter
229:Slow sand filter
172:Stop air blowers
163:Start air blower
127:activated carbon
57:George W. Fuller
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771:Protein skimmer
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696:Ultrafiltration
676:Reverse osmosis
656:Microfiltration
631:Froth flotation
571:Crystallization
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418:Water Treatment
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234:Bank filtration
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178:Wait 30 seconds
175:Close air valve
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850:Unit operation
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561:Chromatography
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301:978-1613000847
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239:Biosand filter
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138:compressed air
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41:drinking water
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766:Mixer-settler
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681:Sedimentation
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105:sedimentation
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98:filter medium
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751:Filter press
736:Depth filter
626:Flocculation
596:Distillation
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115:disinfection
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90:flocculation
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726:Belt filter
691:Sublimation
581:Decantation
327:: 394–443.
134:backwashing
865:Categories
815:Multiphase
746:Evaporator
731:Centrifuge
621:Filtration
616:Extraction
556:Adsorption
546:Absorption
472:References
460:0080212255
428:1583212302
829:Azeotrope
539:Processes
142:fluidized
78:turbidity
843:Concepts
834:Eutectic
786:Scrubber
761:Leachate
641:Leaching
586:Dialysis
223:See also
119:chlorine
817:systems
714:Devices
661:Osmosis
51:History
601:Drying
489:
457:
425:
387:
362:
298:
796:Still
358:-55.
255:Notes
123:ozone
487:ISBN
455:ISBN
423:ISBN
385:ISBN
360:ISBN
296:ISBN
94:alum
86:floc
27:The
329:doi
121:or
59:in
31:or
867::
437:^
356:54
323:.
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263:^
113:A
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47:.
524:e
517:t
510:v
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393:.
368:.
331::
325:L
304:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
