Technology Review
WABAG fltration
Filtration or water and wastewater treatment
WABAG fltration Water fltration
Wastewater fltration
or drinking and process water
or tertiary treatment and water reuse
Filtration is an essential process in water treatment. It is requently the case that it either represents the main processing phase, or is integrated into multi-barrier systems. Many membrane ltration plants also include conventional lters or pre- or post-treatment.
Wastewater ltration is necessary when discharge limits are particularly stringent, e.g. in sensitive areas. In addition, wastewater ltration in combination with disinection also oers a reliable and economic solution or water reuse. WABAG‘s wastewater ltration technology derives rom its experience with water ltration, which has been acquired since the late 1970‘s. It incorporates all the necessary know-how about the particular actors related to wastewater ltration such as the biological activity in the lter bed and control o lter operation with fow variations.
Thus, the continuous development o ltration technology has always been one o WABAG‘s most important objectives and or more than ty years, the t echniques originally developed by Sulzer have been subjected to on-going optimisation. Today, WABAG‘s lter design constitutes an optimum solution or both, single- and multi-layer lters based on various unique eatures.
WABAG fltration
WABAG fltration
rehabilitation
advantages in brie
The available lter foor systems oer optimised solutions or lter rehabilitation. The upgrading o pure water rinsing into air-water backwashing is entirely easible. Extensive experience in lter rehabilitation also allows the optimisation o conventional backwash principles based on continuous fow and sludge water withdrawal channels.
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Outlet regulated (constant water level) deep bed ltration results in high ltration perormance
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Ecient backwashing without lter media loss
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Low backwash water consumption
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Various lter foor systems enable tailor-made solutions and a wide range o l ter media combinations
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Compact design
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Flexible realisation due to a wide range o lter surace areas (10-150 m 2 )
Like water lters, wastewater lters are realised as single- and multilayer lters and oer the s ame eatures.
Kunming, China Drainage Filtration or treatment o surace water Commissioning 2003, capacity 400‘000 m 3 /d
TaiPo, Hongkong Aerated Drainage Filtration or nitrication and multilayer Drainage Filtration or mangenese removal Commissioning 2002, capacity 450‘000 m 3 /d
Berne WWTP, Switzerland Nozzle Floor Filtration or tertiary treatment Commissioning 1984, capacity 14‘400 m 3 /h
Fällanden WWTP, Switzerland Nozzle Floor Filtration or tertiary treatment Commissioning 2003, capacity 1‘800 m 3 /h
Daugava Riga, Latvia GAC Nozzle Floor Filtration or surace water treatment Commissioning 2001, capacity 240‘000 m 3 /d
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Romanshorn WWTP, Switzerland Drainage-Nozzle Floor Filtration or tertiary treatment Commissioning 2007, capacity 1‘080 m 3 /h
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Filtration process Filter eatures or most efcient backwashing
General
WABAG nozzle foor system
The ltration process is based on a downfow operation mode and ltrate outlet regulation. This maintains a constant water level in the lter, which oers the best process conditions or high elimination rates.
This system is based on a concrete nozzle foor with a plenum chamber. The latter is ed rom the ront via a special backwash connection. The nozzle foor can easily be built using shuttering elements.
Deep bed ltration with long lter running times is achieved by the selection o the optimum lter media in a single- or multilayer conguration.The lters can take the orm o rectangular concrete cells (open or closed) or steel vessels.
Excess head Raw water
Filter foor
Washout fap valve
The lter foor is a key system component. The design has to ensure the uniorm distribution o the corresponding media during operation and backwashing, while the construction should be simple, cost-ecient and fexible enough to accommodate various lter dimensions.
Filter media Nozzle foor
WABAG has developed diering types o lter foors, which allow a design in accordance with specic requirements, which is particularly important when existing lters are reurbished. The types o lter foors available are either based on the WABAG nozzle foor or the WABAG drainage system.
Filtrate
Filter underdrain
WABAG drainage system The drainage system consists o cast-in distribution batteries and parallel drainage pipes, which are arranged across the lter bottom. The drainage pipes are surrounded by a s upportive gravel layer. The appropriate orices in the individual drainage pipes allow ltrate to pass out o the lter material and scouring air and water to move in the opposite direction. The drainage pipes are individually connected with the ltrate channel by means o distribution pipes. The gravel layer, drainage pipes and distribution batteries ensure the even distribution o the fushing media.
Filter material Orice or scouring air
An alternative drainage design consists o drainage pipes equipped with nozzles instead o orices. In this case, the drainage pipes are also cast-in and there is no supporting layer o gravel needed.
Supporting layer Air distribuntion pipe Drainage pipe
Scouring air
Filter bottom
Water distribution pipe Backwash water
Backwashing Eective backwashing is vital or the optimised long-term operation o lters. The uniorm distribution o the backwash media and ecient backwash sequences are thereore essential elements in backwashing.
Sludge water extraction is based on the gradual opening o the fap valve, which prevents lter media loss, even where this is highly possible as in the case o specically light media. This allows an additional degree o fexibility with regard to lter media combinations. The repetition o the two phases leads to an ecient backwash with low backwash water use.
As ar as operational costs are concerned, backwash water consumption should be as low as possible and lter media loss has to be avoided.
Backwash water outlet
These objectives are achieved by WABAG lter foor systems and a sophisticated backwash principle (excess head backwash, see below) using an internal fap valve or sludge water withdrawal. The fap valve is either situated on the ront or the rear side o the lter cell, just above the top level o the lter medium. The excess head backwash principle divides the backwash sequence into a rst phase o backwash medium introduction and a second phase o sludge water withdrawal. Backwash medium introduction can t hereore be precisely matched to individual operational conditions.
Scouring air Backwash
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Schematic diagram o the fap valve
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Filtration process Filter eatures or most efcient backwashing
General
WABAG nozzle foor system
The ltration process is based on a downfow operation mode and ltrate outlet regulation. This maintains a constant water level in the lter, which oers the best process conditions or high elimination rates.
This system is based on a concrete nozzle foor with a plenum chamber. The latter is ed rom the ront via a special backwash connection. The nozzle foor can easily be built using shuttering elements.
Deep bed ltration with long lter running times is achieved by the selection o the optimum lter media in a single- or multilayer conguration.The lters can take the orm o rectangular concrete cells (open or closed) or steel vessels.
Excess head Raw water
Filter foor
Washout fap valve
The lter foor is a key system component. The design has to ensure the uniorm distribution o the corresponding media during operation and backwashing, while the construction should be simple, cost-ecient and fexible enough to accommodate various lter dimensions.
Filter media Nozzle foor
WABAG has developed diering types o lter foors, which allow a design in accordance with specic requirements, which is particularly important when existing lters are reurbished. The types o lter foors available are either based on the WABAG nozzle foor or the WABAG drainage system.
Filtrate
Filter underdrain
WABAG drainage system The drainage system consists o cast-in distribution batteries and parallel drainage pipes, which are arranged across the lter bottom. The drainage pipes are surrounded by a s upportive gravel layer. The appropriate orices in the individual drainage pipes allow ltrate to pass out o the lter material and scouring air and water to move in the opposite direction. The drainage pipes are individually connected with the ltrate channel by means o distribution pipes. The gravel layer, drainage pipes and distribution batteries ensure the even distribution o the fushing media.
Filter material Orice or scouring air
An alternative drainage design consists o drainage pipes equipped with nozzles instead o orices. In this case, the drainage pipes are also cast-in and there is no supporting layer o gravel needed.
Supporting layer Air distribuntion pipe Drainage pipe
Scouring air
Filter bottom
Water distribution pipe Backwash water
Backwashing Eective backwashing is vital or the optimised long-term operation o lters. The uniorm distribution o the backwash media and ecient backwash sequences are thereore essential elements in backwashing.
Sludge water extraction is based on the gradual opening o the fap valve, which prevents lter media loss, even where this is highly possible as in the case o specically light media. This allows an additional degree o fexibility with regard to lter media combinations. The repetition o the two phases leads to an ecient backwash with low backwash water use.
As ar as operational costs are concerned, backwash water consumption should be as low as possible and lter media loss has to be avoided.
Backwash water outlet
These objectives are achieved by WABAG lter foor systems and a sophisticated backwash principle (excess head backwash, see below) using an internal fap valve or sludge water withdrawal. The fap valve is either situated on the ront or the rear side o the lter cell, just above the top level o the lter medium. The excess head backwash principle divides the backwash sequence into a rst phase o backwash medium introduction and a second phase o sludge water withdrawal. Backwash medium introduction can t hereore be precisely matched to individual operational conditions.
Scouring air Backwash
Schematic diagram o the fap valve
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WABAG is an international supplier o systems or: n
Drinking water treatment
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Industrial and process water treatment
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Water reclamation
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Sea and brackish water desalination
n
Municipal wastewater treatment
n
Industrial wastewater treatment
n
Sludge treatment
Maintenance & After Sales Services Consulting Operations (DBO, BOT, BOOT)
WABAG is one o the world’s most innovative water
Planning
treatment companies with know-how in specic technologies and in-house developed processes such as: Commissioning ®
n
Fluidised bed biology
FLUOPUR
n
Bioltration
BIOPUR ®
n
Activated sludge processes
Hybrid™, SBR
n
Anaerobic biological
EKJ TM, UASB, an-OPUR TM
Design & Engineering Construction Equipment
WABAG is an international supplier o systems or: n
Drinking water treatment
n
Industrial and process water treatment
n
Water reclamation
n
Sea and brackish water desalination
n
Municipal wastewater treatment
n
Industrial wastewater treatment
n
Sludge treatment
Maintenance & After Sales Services Consulting Operations (DBO, BOT, BOOT)
WABAG is one o the world’s most innovative water
Planning
treatment companies with know-how in specic technologies and in-house developed processes such as: Commissioning ®
n
Fluidised bed biology
FLUOPUR
n
Bioltration
BIOPUR ®
n
Activated sludge processes
Hybrid™, SBR
n
Anaerobic biological processes
EKJ TM, UASB, an-OPUR TM, EGSB
n
Membrane bioreactor
MARAPUR®, Megamodul TM
n
Membrane ltration
RO, MF, UF, NF
n
Denitrication
BIODEN®, ENR®
n
Oxidation processes
ADOX®, BIOZONE®
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Thermal desalination
MED, TVC, MVC, MSF
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Sludge digestion and disintegration
BIOZONE®-AD
Design & Engineering Construction Equipment Supply
The WABAG Group represents a leading multinational player with companies and oces in 18 countries and a ocus on emerging markets in Europe, North Arica, Middle East, South East Asia, China and India.
sustainable solutions. or a better lie.
VA TECH WABAG GmbH Dresdnerstraße 87-91 1200 Vienna, Austria Tel.: +43 1 251 05 0
[email protected] www.wabag.com
VA TECH WABAG Ltd. 11, Murrays Gate Road Alwarpet , Chennai 600 018, India Tel. +91 44 422 323 23
[email protected]
WABAG Water Technology Ltd. Bürglistrasse 31, CH-8401 Winterthur, Switzerland Tel. +41 52 262 43 43
[email protected]