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TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE ( separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F 9/04 ; regeneration of reactants for recirculation into processes, see the relevant places for the processes )
Definition statement
This subclass/group covers:

The physical, chemical and biological treatment of water, waste water or sewage, e.g. by distillation or evaporation, by degassing, by centrifugal separation, by flocculation of suspended impurities or by using plants such as algae. Selection or use of compositions for such treatments. Compositions (per se) specially adapted for water treatment. Softening water and preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents. Aeration of stretches of water. Multistep treatment of water, waste water or sewage. Treatment of sludge and devices therefore, e.g. bioreactors. Sludge treatment covered in this subclass is usually restricted to the treatment of sludge obtained from a water treatment process.

Relationship between large subject matter areas

Separation in general is classified in B01D.

Making potable water by desalination or solar evaporation is classified in C02F and apparatus for separation in general are classified in B01D

References relevant to classification in this subclass
This subclass/group does not cover:
Processes for making harmful chemical substances harmless by effecting a chemical change in the substances
Settling tanks and filter devices in general
In-situ ground water treatment
Adding materials to water to prevent corrosion
Cleaning or keeping clear the surface of open water, e.g. the sea
Methods for obtaining or collecting drinking water or tap water
Treating radioactively-contaminated liquids
Informative references
Attention is drawn to the following places, which may be of interest for search:
Treating waste water and sewage on vessels
Special rules of classification within this subclass

Devices are only classified in detail if there is no appropriate, more general place available and if they are clearly related to the water treatment aspect (i.e. if they are not universally applicable). Important (invention-related) information is classified with CPC classification symbols, e.g. C02F 1/02, other (secondary) information with additional information symbols, e.g. C02F 1/02. The following additional information symbols are available:

Symbols for specifying the nature of the contaminant
Symbols for specifying the nature of water, waste water or sludge to be treated
Symbols for details of the apparatus used for treatment of water, wastewater or sludge
Symbols for specifying details of the apparatus and plants for the biological treatment of water, wastewater or sewage
Symbols for controlling or monitoring parameters in water treatment.
Symbols for specifying general aspects of water treatment
Symbols for specific treatment goals
Symbols for the use of specific compounds in water treatment
Symbols for the location of water treatment or water treatment device
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Sludge
aqueous suspension of solids resulting from water treatment processes and having a solids concentration of typically more than 2 g/L
Treatment of water, waste water, or sewage (C02F 3/00 to C02F 9/00 take precedence )
Definition statement
This subclass/group covers:

This group covers processes and apparatus relating to physical and chemical water treatment (ultrapure water, potable water, wastewater).

Treatment concerns only water, waste water or sewage and not any liquids

References relevant to classification in this group
This subclass/group does not cover:
Biological water treatment
Softening water, preventing scale
Aeration of stretches of water
Multistage treatment of water
{Processes for the treatment of water whereby the filtration technique is of importance (C02F 1/44 takes precedence; construction of filters in general B01D 24/00 to B01D 41/00) }
Definition statement
This subclass/group covers:

Methods for separation of water and particles suspended in water.

References relevant to classification in this group
This subclass/group does not cover:
Membrane treatment
Filter devices
Informative references
Attention is drawn to the following places, which may be of interest for search:
Membrane filters
Special rules of classification within this group

The head group should only be used if none of the more specific groups is appropriate.

{using small portable filters for producing potable water, e.g. personal travel or emergency equipment, survival kits, combat gear (C02F 1/003 takes precedence ) }
Definition statement
This subclass/group covers:

This class relates to small portable filters, which are mostly pocket-sized, e.g. filters integrated in drinking straws, canteens or bottles. Bottle-filters can be further characterised using the symbol C02F 2307/02.

References relevant to classification in this group
This subclass/group does not cover:
Household type filters
Informative references
Attention is drawn to the following places, which may be of interest for search:
Indexing symbol for bottle-filters
{using household-type filters for producing potable water, e.g. pitchers, bottles, faucet mounted devices (C02F 9/005 takes precedence ) }
Definition statement
This subclass/group covers:

This class contains household filters, e.g. pitchers, larger bottles, cartridges, faucet mounted devices, filters useable either in commercial or residential establishments. Additional details can be classified using Indexing symbols C02F 2307/02 - C02F 2307/06 (see the informative references).

References relevant to classification in this group
This subclass/group does not cover:
Small-scale multistage treatment apparatus
Informative references
Attention is drawn to the following places, which may be of interest for search:
Apparatus for making beverages including water filters
Filter condition indicators
Liquid dispensers
Filter as part of a bottle
Filter being part of a pitcher or jug
Filter being mounted on a faucet or showerhead
{using large scale industrial sized filters}
Definition statement
This subclass/group covers:

To be used for large scale (industrial scale) mechanical filtration, e.g. use of a sand filter, rapid filtration. Typical applications are filters in drinking water purification plants, post filtration in wastewater treatment plants, water filtration for industrial water stream.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Filters in general
Biofilters
{Systems or processes based on supernatural or anthroposophic principles, cosmic or terrestrial radiation, geomancy or rhabdomancy}
Definition statement
This subclass/group covers:

Systems or processes based on supernatural or anthroposophic principles. This class is used for all esoteric applications which claim implausible effects (lack of scientific explanation, quackery).

Informative references
Attention is drawn to the following places, which may be of interest for search:
Homeaopathy, esoteric applications
Screening of terrestrial radiation
Radio-esthesis, dowsing
Special rules of classification within this group

Clear treatment steps, e.g. magnetic treatment, irradiation can be classified by adding the corresponding additional information symbol (C02F 1/48, C02F 1/30; etc.).

{Water distributors either inside a treatment tank or directing the water to several treatment tanks; Water treatment plants incorporating these distributors, with or without chemical or biological tanks ( for settling tanks B01D 21/24) }
Definition statement
This subclass/group covers:

This class is used for any devices directing the water to be treated into the treatment tank or installation, e.g. pipes, connecting vessels.

References relevant to classification in this group
This subclass/group does not cover:
Water distributors for settling tanks
{Control or steering systems not provided for elsewhere in subclass C02F}
Definition statement
This subclass/group covers:

Control of parameters in the physical or chemical water treatment processes

References relevant to classification in this group
This subclass/group does not cover:
Control of flocculation processes
Control of biological water treatment processes
Informative references
Attention is drawn to the following places, which may be of interest for search:
Control in general
Control parameters and systems
by heating ( methods of steam generation F22B ; preheating boiler feed-water or accumulating preheated boiler feed-water F22D)
Definition statement
This subclass/group covers:

Treatment of water by heating

References relevant to classification in this group
This subclass/group does not cover:
Methods of steam generation
Preheating boiler feed-water
Informative references
Attention is drawn to the following places, which may be of interest for search:
Heat sterilisation for pharmaceuticals
General heat sterilisation
Special rules of classification within this group

The groups C02F 1/02 to C02F 1/18 cover applications in which the water treatment process concerns mainly the heating of the water to be treated, e.g. disinfection, evaporation, distillation.

by distillation or evaporation
Definition statement
This subclass/group covers:

Treatment of water using distillation, apparatus details should always be classified in the corresponding classes in B01D.

Informative references
Attention is drawn to the following places, which may be of interest for search:
General distillation and evaporation, devices
Special rules of classification within this group

Seawater desalination can be indexed with the symbol C02F 2103/08.

{by means of vapour compression}
Definition statement
This subclass/group covers:

Treatment of water, waste water or sewage by vapour compression

Informative references
Attention is drawn to the following places, which may be of interest for search:
Evaporating with vapour compression
{Prevention of deposits}
Definition statement
This subclass/group covers:

Prevention of deposits in the context of distillation or evaporation.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Electrochemical prevention or elimination of deposits
Softening water, scale prevention
Elimination of deposits, scale removal or prevention being a secondary aspect
{for obtaining ultra-pure water}
Definition statement
This subclass/group covers:

Distillation / evaporation process for obtaining ultrapure water.

Special rules of classification within this group

Symbol C02F 2103/04 should be used for all other processes producing ultrapure water.

{under vacuum produced by a barometric column}
Definition statement
This subclass/group covers:

Treatment of water, waste water or sewage by distillation or evaporation under vacuum produced by a barometric column

Informative references
Attention is drawn to the following places, which may be of interest for search:
Vacuum distillation using a barometric column
{Purification of waste water by evaporation}
Definition statement
This subclass/group covers:

Treatment of wastewater by evaporation and distillation.

Special rules of classification within this group

The specific type of wastewater can be further characterised using the symbols under C02F 2103/00 - C02F 2103/42.

Flash evaporation
Definition statement
This subclass/group covers:

Treatment of water, waste water or sewage by flash evaporation, i.e. evaporation under (non-barametric) vacuum or by sudden expansion

Informative references
Attention is drawn to the following places, which may be of interest for search:
Flash distillation
Thin film evaporation
Definition statement
This subclass/group covers:

Treatment of water, waste water or sewage by evaporating a thin film of liquid on heated surfaces, packing elements or by using a falling film evaporator

Relationship between large subject matter areas

Apparatus for filtration like thin film evaporator concerning liquid purification is classified in B01D

When the liquid purification concerns water, then it's also classified in C02F 1/08

Informative references
Attention is drawn to the following places, which may be of interest for search:
Film evaporation
Thin layer evaporation
by direct contact with a particulate solid or with a fluid, as a heat transfer medium
Definition statement
This subclass/group covers:

Treatment of water, waste water or sewage by putting the water in direct contact with the heat carrier medium

Informative references
Attention is drawn to the following places, which may be of interest for search:
Evaporating with heated gases in contact with the liquid
Spray evaporation
Definition statement
This subclass/group covers:

Treatment of water, waste water or sewage by dispersing the water in form of droplets (spray) in a gas for evaporating

Informative references
Attention is drawn to the following places, which may be of interest for search:
Evaporating by spraying
using solar energy
Definition statement
This subclass/group covers:

Treatment of water, waste water or sewage by using solar heat directly or indirectly for evaporating water

Informative references
Attention is drawn to the following places, which may be of interest for search:
Evaporating in general using solar energy
using waste heat from other processes
Definition statement
This subclass/group covers:

Treatment of water, waste water or sewage by using waste heat from other processes, e.g. from engine cooling circuits, power plants or industrial production processes

Informative references
Attention is drawn to the following places, which may be of interest for search:
Evaporating using waste energy
Transportable devices to obtain potable water
Definition statement
This subclass/group covers:

Transportable device and process using such device for treating water by distillation.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Mobile apparatus and plants in general
Mobile biological apparatus and plants in general
by degassing, i.e. liberation of dissolved gases ( degasification of liquids in general B01D 19/00 ; arrangement of degassing apparatus in boiler feed supply F22D)
Definition statement
This subclass/group covers:

Processes removing dissolved gases such as oxygen, carbon dioxide or halogens. This class is also used for processes directed at removing volatile organic or inorganic compounds, e.g. ammonia. This includes stripping and vacuum processes.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Apparatus for degasification of liquids in general
Arrangement of degassing apparatus in boiler feed supply
Special rules of classification within this group

Indexing symbols for the compounds to be removed should be used if available (C02F 2101/00 - C02F 2101/40).

by freezing
Definition statement
This subclass/group covers:

Processes for cleaning water by freezing, separation of ice and slush from water and subsequent melting of ice and slush, e.g. freeze desalination.

Special rules of classification within this group

Freeze-desalination using methane-hydrates (clathrates) is classified as a combination of C02F 1/22 and C02F 1/265.

by flotation (C02F 1/465 takes precedence )
Definition statement
This subclass/group covers:

Water treatment processes by flotation, e.g. for separating solids and liquids dispersed in water by using microbubbles, dissolved air flotation (DAF).

References relevant to classification in this group
This subclass/group does not cover:
Electroflotation
Informative references
Attention is drawn to the following places, which may be of interest for search:
Flotation devices
by extraction
Definition statement
This subclass/group covers:

Treatment of water, waste water or sewage by extraction, e.g. removing pollutant from water by extraction, solvent extraction.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Solvent extraction
by sorption ( using ion-exchange C02F 1/42 ; sorbent compositions B01J)
Definition statement
This subclass/group covers:

Treatment of water by sorption, removal of a compound by adsorption on a generally solid sorbent, regardless of the mechanism involved (chemisorption, complexation).

References relevant to classification in this group
This subclass/group does not cover:
Treatment of water, waste water or sewage by ion exchange
Informative references
Attention is drawn to the following places, which may be of interest for search:
Sorbents in general
Special rules of classification within this group

If more than one sorbent is used the head group should be used in combination with the more specific symbols chosen from C02F 2001/422 to C02F 2001/427.

{using inorganic sorbents}
Definition statement
This subclass/group covers:

Water treatment using natural and synthetic inorganic sorbents. Examples for inorganic sorbents include zeolites, clays, silicagel, metal-hydroxides. Ion exchange occurring at the surface of inorganic sorbents is also classified here.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Inorganic sorbents
{using coal, charred products, or inorganic mixtures containing them}
Definition statement
This subclass/group covers:

Activated carbon and other coal or carbon based adsorbents, Powdered activated carbon (PAC), carbon black

Informative references
Attention is drawn to the following places, which may be of interest for search:
Carbon based sorbents
Special rules of classification within this group

Only to be used if the carbonaceous compound is the active adsorbent (not for carriers).

{using synthetic organic sorbents}
Definition statement
This subclass/group covers:

Treatment of water, waste water or sewage by sorption using synthetic organic sorbents, e.g. organic adsorbents not occurring naturally, e.g. synthetic polymers.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Sorbents comprising synthetic macromolecular compounds
{using natural organic sorbents or derivatives thereof}
Definition statement
This subclass/group covers:

Sorption using natural organic sorbents such as algae, compost, humic acids, cellulose, etc.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Sorbents comprising naturally occurring natural macromolecular compounds
{using composite sorbents, e.g. coated, impregnated, multi-layered}
Definition statement
This subclass/group covers:

Processes using coated, impregnated, hybrid and multi-layered sorbents.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Coated solid sorbents
Special rules of classification within this group

Use of layered adsorbents should be classified as combination of class and additional symbol, e.g. C02F 1/288 and C02F 1/283.

by irradiation
Definition statement
This subclass/group covers:

Processes for treating water, waste water or sewage by using radiation sources, e.g. plasma, ionised gas. Irradiation with sunlight should be classified here only if the effect is not due to the UV radiation and if the effect is not achieved by heating.

{with microwaves}
Definition statement
This subclass/group covers:

Treatment of water with microwave radiation.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Disinfecting and sterilising with microwaves
Special rules of classification within this group

If microwaves are primarily used for heating C02F 1/02 is used.

with ultra-violet light
Definition statement
This subclass/group covers:

Processes using ultraviolet light (light having a wavelength of approximately 100-400 nm).

Informative references
Attention is drawn to the following places, which may be of interest for search:
Disinfection and sterilisation using ultraviolet light
Special rules of classification within this group

C02F 1/325 should always be used when apparatus details are mentioned. Photocatalysis is classified by combining C02F 1/32 or C02F 1/325 with C02F 1/74 and C02F 2305/10.

{Irradiation devices or lamp constructions}
Definition statement
This subclass/group covers:

Devices for UV treatment.

Special rules of classification within this group

Details should be classified by using the symbols under C02F 2201/32.

with mechanical oscillations
Definition statement
This subclass/group covers:

Processes using cavitation for the destruction of particles and substances in the water to be treated. Mechanical creation by nozzles, valves, throttles or pumps.

Informative references
Attention is drawn to the following places, which may be of interest for search:
General mixing
Special rules of classification within this group

Can be given as additional information for sludge treatment.

ultrasonic vibrations
Definition statement
This subclass/group covers:

Processes using ultrasonic transducer or similar devices to create ultrasound.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Disinfection and sterilisation using ultrasonic devices
Special rules of classification within this group

If ultrasonic waves are created mechanically, e.g. with a nozzle, classify in C02F 1/34.

by centrifugal separation
Definition statement
This subclass/group covers:

Processes for treatment of water, waste water or sewage in which separation is achieved by using centrifugal forces, e.g. hydrocyclones, hydrodynamical separators.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Centrifugal separators in general
{by centrifuging suspensions ( centrifuges B04B) }
Definition statement
This subclass/group covers:

Centrifugal separation for treating water.

References relevant to classification in this group
This subclass/group does not cover:
Centrifuges
Centrifugal separation of sludge
Devices for separating or removing fatty or oily substances or similar floating material ( cleaning or keeping clear the surface of open water from oil or like materials E02B 15/04 ; devices in sewers for separating liquid or solid substances from sewage E03F 5/14 , e.g. for use in drains leading to the sewer E03F 5/16)
Definition statement
This subclass/group covers:

Devices for removing fatty or oily substances or similar floating material,, e.g. grease traps, oil water separators or oil skimmers

Informative references
Attention is drawn to the following places, which may be of interest for search:
Separation of liquids
Devices for removing oil from open water surfaces
Devices in sewers for removing fat and oil from sewage
Devices for use in drains leading to the sewer
Special rules of classification within this group

Group is at present not used for classification, use C02F 1/40.

by ion-exchange ( ion-exchange in general B01J)
Definition statement
This subclass/group covers:

Use of resin type ion exchangers for treatment of water, waste water or sewage

Informative references
Attention is drawn to the following places, which may be of interest for search:
Dishwashers comprising water softeners
Ion-exchange in general
Washing machines comprising water softeners
Special rules of classification within this group

Ion exchange using zeolites and other inorganic ion exchangers should be classified in C02F 1/281 (sorption with inorganic sorbents).

by dialysis, osmosis or reverse osmosis { ( general membrane separation processes B01D 61/00 , membrane modules B01D 63/00 , electrodialysis C02F 1/4693 , combination of membrane modules and bioreactors C02F 3/1268) }
Definition statement
This subclass/group covers:

Water treatment processes using membrane separation.

References relevant to classification in this group
This subclass/group does not cover:
Electrodialysis
Membrane bioreactor systems
Submerged membrane bioreactors
Anaerobic membrane bioreactors
Informative references
Attention is drawn to the following places, which may be of interest for search:
Membrane separation, devices
{by reverse osmosis}
Definition statement
This subclass/group covers:

Treatment of water, waste water, sewage by reverse osmosis

Informative references
Attention is drawn to the following places, which may be of interest for search:
Reverse osmosis processes in general
{by nanofiltration}
Definition statement
This subclass/group covers:

Treatment of water, waste water, sewage by nanofiltration

Informative references
Attention is drawn to the following places, which may be of interest for search:
Nanofiltration processes in general
{by ultrafiltration or microfiltration}
Definition statement
This subclass/group covers:

Treatment of water, waste water, sewage by ultrafiltration or microfiltration

Informative references
Attention is drawn to the following places, which may be of interest for search:
Ultrafiltration processes in general
Microfiltration processes in general
by electrochemical methods
Definition statement
This subclass/group covers:

Electrochemical methods for treating water, if no electrical current (static electrical field) is used C02F 1/48 applies.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Electrolytic processes for producing compounds
Electroplating
Special rules of classification within this group

When classifying in C02F 1/46 the additional symbols under C02F 2201/46 should be used for additional information.

{for desalination of seawater or brackish water}
Definition statement
This subclass/group covers:

All electrochemical seawater desalination processes not covered by C02F 1/469.

{for producing oligodynamic substances to desinfect the water}
Definition statement
This subclass/group covers:

Production of disinfecting metallic ions, e.g. Ag, Cu, by electrolysis.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Non-electrolytic oligodynamic treatment
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Oligodynamic substances
active substances in very small quantities, used especially to describe the sterilizing effect of some heavy metals against bacteria
{using electrical discharges}
Definition statement
This subclass/group covers:

Treatment of water by applying electrical discharges, generally by using high voltages.

{Devices therefor; Their operating or servicing}
Definition statement
This subclass/group covers:

Electrolytic devices used for water treatment, for additional details not covered by classes in C02F the symbols C02F1/461B2D - C02F1/461B2L2B2, C02F 1/46176 and C02F1/461B6B - C02F 2001/46195 can be used.

{Electrodes}
Definition statement
This subclass/group covers:

Electrodes for water treatment purposes.

Special rules of classification within this group

Additional information can be given by using the symbols C02F 2001/46119 - C02F 2001/46166.

{Electrodes in particulate form or with conductive and/or non conductive particules between them}
Definition statement
This subclass/group covers:

Electrolytic cells where the space between anode and cathode is filled with a bed of particles (static or fluidised bed) and electrodes which are themselves comprised of particles.

{for producing "ionised" acidic or basic water}
Definition statement
This subclass/group covers:

Production of acidic, oxidising water at the anode and alkaline, reducing water at the cathode (separation of the streams).

Special rules of classification within this group

If the water is primarily used for oxidation C02F 1/4672 applies. For electrochemical reduction use C02F 1/4676. Additional symbols C02F 2001/46185 - C02F 2001/46195 are available.

by electrocoagulation
Definition statement
This subclass/group covers:

Electrochemical production of coagulant, e.g. iron or aluminium ions, usually with dissolution of the electrode.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Chemical flocculation or precipitation
by electroflotation
Definition statement
This subclass/group covers:

Electrochemical production of microbubbles for flotation.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Water treatment by flotation
{by electrooxydation}
Definition statement
This subclass/group covers:

Electrochemical production of oxidants (oxygen, ozone, hydroxyl radicals) at the anode for disinfection and oxidation of organic and inorganic substances.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Creating reactive oxygen species
{by electroreduction}
Definition statement
This subclass/group covers:

Electrochemical production of reducing agents (hydrogen), occurring at the cathode.

{of metals}
Definition statement
This subclass/group covers:

Reduction of metals (electroplating) is included in this group.

by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
Definition statement
This subclass/group covers:

All processes where an electrical field is the driving force for separating substances in water treatment.

{Capacitive deionisation}
Definition statement
This subclass/group covers:

Removing ions from water by capacitive deionisation.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Capacitors
{electrodialysis}
Definition statement
This subclass/group covers:

Treatment of water, waste water, sewage by electrodialysis

Informative references
Attention is drawn to the following places, which may be of interest for search:
Electrodialysis processes in general
{electrodeionisation}
Definition statement
This subclass/group covers:

Use of an electrodialysis cell wherein one or more of the compartments is filled with ion-exchange material.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Electrodeionisation processes in general
{electro-osmosis}
Definition statement
This subclass/group covers:

Treatment of water, waste water, sewage by using the effect of electro-osmetic flow, i.e. the motion of liquid induced by an applied electrical potential across a porous material such as a capillary tube, membrane or microchannel.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Electro-osmosis processes in general
with magnetic or electric fields (C02F 1/46 takes precedence )
Definition statement
This subclass/group covers:

Includes treatment with an electrical field (no electrical current in the water).

References relevant to classification in this group
This subclass/group does not cover:
Water treatment by electrochemical methods
Informative references
Attention is drawn to the following places, which may be of interest for search:
Magnetic or electrostatic separation
Eliminating or preventing deposits, scale prevention
{using permanent magnets}
Definition statement
This subclass/group covers:

Treatment with permanent magnets.

{using electromagnets}
Definition statement
This subclass/group covers:

Treatment using electromagnets.

{using high frequency electromagnetic fields, e.g. pulsed electromagnetic fields}
Definition statement
This subclass/group covers:

Treatment of water by using high frequency electromagnetic fields, e.g. for reducing scale in pipelines. Frequencies above 500 Hz are considered "high frequency" in the present context.

{for separation of magnetic materials, e.g. magnetic flocculation}
Definition statement
This subclass/group covers:

Water treatment processes where a magnetic field is used for separation (includes removing loaded sorbents from water).

by addition or application of a germicide or by oligodynamic treatment ( {C02F 1/46 H, C02F 1/467 , C02F 1/76 take precedence } )
Definition statement
This subclass/group covers:

Treatment of water by addition of chemicals and compounds that adversely affect the ability of microorganisms, animals and plants to survive or reproduce.

References relevant to classification in this group
This subclass/group does not cover:
Electrochemical methods for producing oligodynamic substances to disinfect the water
Electrochemical disinfection
Oxidation with halogens or compounds of halogens
Informative references
Attention is drawn to the following places, which may be of interest for search:
Chemicals for disinfection in general
Methods or apparatus for disinfection in general
Synonyms and Keywords

In patent documents the following words/expressions are often used as synonyms:

EN
disinfect, sterilize, sanitize
DE
sterilisieren, desinfizieren,
FR
stériliser, désinfecter, aseptiser
{by oligodynamic treatment}
Definition statement
This subclass/group covers:

Treatment of water by oligodynamic effect created by the addition of metallic ions of mercury, silver, copper, iron, lead, zinc, bismuth, gold, aluminium.

by flocculation or precipitation of suspended impurities { (C02F 1/463 takes precedence ) }
Definition statement
This subclass/group covers:

Processes and related installations or apparatus for water treatment by causing coagulation or flocculation. Crystallisation processes are to be included when used for water treatment.

References relevant to classification in this group
This subclass/group does not cover:
Electrocoagulation
Informative references
Attention is drawn to the following places, which may be of interest for search:
Sedimentation
B0D21
Flotation processes
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Coagulation
breaking of the electrostatic repulsion to allow growth of "nuclei".
Flocculation
growth of "flocs" mostly by addition of separated nuclei.
Synonyms and Keywords

In patent documents the following terms are often used:

EN
Coagulation, flocculation, precipitation, agglomeration, weighting, ballast
DE
Koagulation, Flockung, Fällung, Agglomeration, Beschwerung, ballast
FR
Coagulation, floculation, précipitation, agglomération, pondération, ballast, lesté.
{Regulation methods for flocculation or precipitation}
Definition statement
This subclass/group covers:

Water treatment documents where the invention information relates to the regulation of coagulation and flocculation, or to the way the coagulated or precipitated matter is separated when no other subclass is provided.

References relevant to classification in this group
This subclass/group does not cover:
Control for chemical and physical water treatment
Control for biological water treatment
Informative references
Attention is drawn to the following places, which may be of interest for search:
Control in general
Control parameters
Special rules of classification within this group

Use the Indexing Codes under C02F 2209/00 - C02F 2209/445 if applicable.

{Processes for facilitating the dissolution of solid flocculants in water}
Definition statement
This subclass/group covers:

This group concerns processes for improving the dissolution of additives before coagulation or flocculation is performed.

{using inorganic agents}
Definition statement
This subclass/group covers:

Water treatment using inorganic coagulants or flocculants.

Special rules of classification within this group

Inorganic polymers should not receive the C02F 1/56 class or Indexing symbol.

{using basic salts, e.g. of aluminium and iron}
Definition statement
This subclass/group covers:

Treament of water by addition of inorganic salts with alkaline character.

{using magnesium compounds and phosphoric acid for removing ammonia}
Definition statement
This subclass/group covers:

Treatment of water in the MAP process, i.e. magnesium ammonium phosphate precipitation process to remove ammonium nitrogen from waste water

{using natural chemical compounds}
Definition statement
This subclass/group covers:

Treatment of water by flocculation or precipitation of suspended impurities with the use of natural compounds chemically unmodified and unformulated; e.g. chitosan, bacterial products.

Special rules of classification within this group

Compounds unmodified and unformulated. Formulations comprising them should be classified in C02F 1/5272.

{using specific organic precipitants}
Definition statement
This subclass/group covers:

Treatment of water by flocculation or precipitation of suspended impurities with the use of defined organic compounds and formulations for water treatment, e.g. formulations comprising lignin as coagulant.

{Installations for water purification using chemical agents}
Definition statement
This subclass/group covers:

Apparatuses and installations comprising devices for water coagulation and precipitation.

{Processes or devices for preparing lime water}
Definition statement
This subclass/group covers:

Water treatment including the preparation of lime water.

using organic material
Definition statement
This subclass/group covers:

Water treatment by organic compounds including oligomers

Special rules of classification within this group

Non macromolecular compounds. Classify polymers under C02F 1/56

{Phosphorus compounds}
Definition statement
This subclass/group covers:

Water treatment by organic compounds comprising phosphorus functional groups.

{Silicon compounds}
Definition statement
This subclass/group covers:

Water treatment by organic compounds comprising silicon functional groups.

{Tensides}
Definition statement
This subclass/group covers:

Water treatment by surface active organic compounds.

Macromolecular compounds
Definition statement
This subclass/group covers:

Water treatment with organic polymers.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Inorganic polymeric compounds
Polymers in general
by removing specified dissolved compounds ( using ion-exchange C02F 1/42 ; softening water C02F 5/00)
Definition statement
This subclass/group covers:

Documents related to removal of specific polluting or unwanted compounds from water.

References relevant to classification in this group
This subclass/group does not cover:
Ion-exchange
Softening water
Special rules of classification within this group

The classes C02F 1/58 - C02F 1/645 should only be used if no other class is applicable, for specifying the compound to be removed the Indexing symbols in the range C02F 2101/00 - C02F 2101/40 should be given. Classification of the method and the apparatus used in C02F is also mandatory.

by neutralisation; pH adjustment ( for degassing C02F 1/20 ; using ion-exchange C02F 1/42 ; for flocculation or precipitation of suspended impurities C02F 1/52 ; for removing dissolved compounds C02F 1/58)
Definition statement
This subclass/group covers:

Processes directed to obtain or avoid a particular pH value or range in water treatment.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Degassing
Ion-exchange
Flocculation and precipitation
Removing dissolved compounds
Special rules of classification within this group

Classify here when invention information concerns pH adjustment. In all other cases involving pH measurement or adjustment use symbols from C02F 1/66 or C02F 2209/06.

by addition of specified substances, e.g. trace elements, for ameliorating potable water ( medicinal water A61K)
Definition statement
This subclass/group covers:

Adding specific substances, e.g. vitamins, trace elements or carbon dioxide to water.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Medicinal water
{by addition of solid materials for removing an oily layer on water}
Definition statement
This subclass/group covers:

Addition of adsorbents to the water for removing oil from water (remediating oil spills).

{by addition of complex-forming compounds}
Definition statement
This subclass/group covers:

Water treatment by addition of any molecules forming a complex with a target, regardless their other characteristics or use

Synonyms and Keywords

In patent documents the following terms are often used:

sequestering, complexing, scavenging, chelating

{Devices for dosing the additives}
Definition statement
This subclass/group covers:

Water treatment devices for adding chemicals to water in a controlled manner.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Dosing of halogens in gaseous form
{Devices for dosing liquid additives}
Definition statement
This subclass/group covers:

Water treatment devices for adding chemicals in liquid form.

{Devices for dosing solid compounds}
Definition statement
This subclass/group covers:

Water treatment devices for adding chemicals in solid form to water in a controlled manner.

{Devices in which the water progressively dissolves a solid compound}
Definition statement
This subclass/group covers:

Water treatment devices for adding chemicals to water in a controlled manner exploiting the flow of water which gradually dissolves the product to be dosed. Includes the use of tablets or granular products enclosed in a device.

by reduction { (C02F 1/4676 takes precedence ) }
Definition statement
This subclass/group covers:

Water treatment processes wherein pollutants are chemically reduced.

References relevant to classification in this group
This subclass/group does not cover:
Electrochemical reduction processes
{Reduction by metals}
Definition statement
This subclass/group covers:

Water treatment processes wherein pollutants are reduced by metallic compounds (in zero valence state).

by oxidation { (C02F 1/4672 takes precedence ) }
Definition statement
This subclass/group covers:

Water treatment processes wherein pollutants are chemically oxidized.

References relevant to classification in this group
This subclass/group does not cover:
Electrochemical oxidation processes
{Oxidation by peroxides}
Definition statement
This subclass/group covers:

Water treatment processes wherein pollutants are oxidized by peroxides.

{by catalytic oxidation}
Definition statement
This subclass/group covers:

Water treatment processes wherein pollutants are oxidized by catalytic reactions. Includes the use of heterogeneous catalysts.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Fenton type oxidation
Photocatalysts
Special rules of classification within this group

Photocatalysis is classified by combining C02F 1/32 or C02F 1/325 with C02F 1/725 and C02F 2305/10.

{using pure oxygen or oxygen rich gas}
Definition statement
This subclass/group covers:

Water treatment processes wherein pollutants are oxidized by pure oxygen or oxygen enriched gas.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Reactive oxygen species, singlet oxygen, OH radical
with air ( aeration of stretches of water C02F 7/00)
Definition statement
This subclass/group covers:

Water treatment processes wherein pollutants are oxidized by air.

References relevant to classification in this group
This subclass/group does not cover:
Activated sludge processes using surface aeration
Activated sludge processes using diffusers
Aeration of stretches of water
with halogens or compounds of halogens { (C02F 1/4674 takes precedence ) }
Definition statement
This subclass/group covers:

Water treatment processes wherein pollutants are oxidized by halogens.

References relevant to classification in this group
This subclass/group does not cover:
Electrochemical oxidation using halogens
{Devices for the addition of such compounds in gaseous form}
Definition statement
This subclass/group covers:

Water treatment devices for adding halogens in gaseous form to water in a controlled manner.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Dosing of substances in general
{by means of halogens other than chlorine or of halogenated compounds containing halogen other than chlorine}
Definition statement
This subclass/group covers:

Water treatment processes wherein pollutants are oxidized by halogens explicitly different from chlorine, e.g. bromine.

with ozone { (C02F 1/4672 takes precedence ) }
Definition statement
This subclass/group covers:

Water treatment processes wherein pollutants are oxidized by ozone.

References relevant to classification in this group
This subclass/group does not cover:
Electrochemical oxidation using ozone
Biological treatment of water, waste water, or sewage { (C02F 1/006 takes precedence ) }
Definition statement
This subclass/group covers:

This group covers processes relating to biological water treatment. Devices are only classified in detail if there is no appropriate, more general place available and if they are clearly related to the water treatment aspect (not universally applicable).

References relevant to classification in this group
This subclass/group does not cover:
Water distributors
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Aerobic
presence of dissolved oxygen
Anoxic
oxygen not present as dissolved oxygen but in the form of nitrate, sulfate, etc.
Anaerobic
absence of oxygen
{Combined electrochemical biological processes ( aeration by electrolytically produced oxygen bubbles C02F 3/202) }
Definition statement
This subclass/group covers:

Processes in which electrochemical treatment and biological treatment are directly combined, e.g. the electrodes being covered by a biofilm or electrodes being directly immersed in an activated sludge tank.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Electrochemical water treatment in general
Electrochemical aeration
{Regulation methods for biological treatment}
Definition statement
This subclass/group covers:

To be used if the control of a biological water treatment process is the main invention.

References relevant to classification in this group
This subclass/group does not cover:
Control of physical and chemical water treatment processes
Control of flocculation or precipitation processes
Informative references
Attention is drawn to the following places, which may be of interest for search:
Control in general
Control parameters
Special rules of classification within this group

Symbols for the specific controlled parameters should be used if possible (C02F 2209/00-C02F 2209/445).

Aerobic processes
Definition statement
This subclass/group covers:

All aerobic water treatment processes, which are not covered by the following more specific groups.

using trickle filters
Definition statement
This subclass/group covers:

Trickling filters, i.e. biofilm reactors where the filter medium is not submerged in the water to be treated.

{Devices for distributing water over trickle filters}
Definition statement
This subclass/group covers:

Devices for distributing the water over the filter such as rotating arms, sprinklers.

{Soil filtration}
Definition statement
This subclass/group covers:

Filters using the soil as filter medium, the filters can be arranged in a column above the ground.

using submerged filters
Definition statement
This subclass/group covers:

Biofilters where the filter medium is completely submerged in the water to be treated.

Special rules of classification within this group

The filter medium (fillings, grids, packing elements) is classified in C02F 3/10 and subgroups.

using moving contact bodies
Definition statement
This subclass/group covers:

This class contains processes which use larger biofilm carriers which are in movement in the reactor. Rotating biological contactors are classified in C02F 3/082.

Special rules of classification within this group

Not for smaller biofilm carriers such as used in fluidised bed reactors. These should be classified in C02F 3/085. The carrier could be classified in C02F 3/10 and subgroups.

Packings; Fillings; Grids ( packing elements in general B01J 19/30 , B01J 19/32)
Definition statement
This subclass/group covers:

Packings, fillings and grids used as biofilm carrier (shape, arrangement, material).

Informative references
Attention is drawn to the following places, which may be of interest for search:
Packed scrubbers
B01D47/54
Separating processes characterised by the packing of the sorbent material
Packing elements
{Arranged-type packing, e.g. stacks, arrays}
Definition statement
This subclass/group covers:

Biological treatment of water, waste water or sewage by aerobic processes using arrangement of a plurality of tanks, packings, grids, disks in stacks, arrays.

{Permeable membranes}
Definition statement
This subclass/group covers:

Membrane acting as support for the biofilm (not primarily for separation or aeration).

Special rules of classification within this group

In case the membrane is used primarily for separating activated sludge or other substances from water C02F 3/1268, C02F 3/1273 and C02F 3/2853 should be used.

{Textile-type packing}
Definition statement
This subclass/group covers:

Textiles acting as biofilm support.

{Granular carriers}
Definition statement
This subclass/group covers:

Granular carrier used as a packing or filling.

{Characterized by the chemical composition}
Definition statement
This subclass/group covers:

Packing, filler or carrier defined by the chemical composition, e.g. carbon based, inorganic, gels, polymers, etc.

Activated sludge processes
Definition statement
This subclass/group covers:

This group comprises all aerobic processes in which the microorganisms are present in the form of an activated sludge, i.e. located on or in flocs which are suspended in the water to be treated.

{Multistep treatment}
Definition statement
This subclass/group covers:

The treatment steps are carried out in different treatment tanks.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Sludge treatment
Special rules of classification within this group

Treatment with several steps carried out in a single tank should be classified in C02F 3/1263 (SBR).

{Combinations of activated sludge treatment with precipitation, flocculation, coagulation and separation of phosphates}
Definition statement
This subclass/group covers:

Phosphate removal by chemical precipitation in combination with activated sludge treatment, e.g. by dosing salts of iron or aluminium directly into the activated sludge tank.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Precipitation and flocculation
Phosphorous compounds
Special rules of classification within this group

If precipitation and separation is performed as a separate treatment, e.g. after the clarifier, C02F 1/5245 should be used.

{comprising treatment of the recirculated sludge}
Definition statement
This subclass/group covers:

Reduction of surplus sludge by heating, ultrasonic treatment, oxidation carried out in a side stream (e.g. return sludge stream).

{comprising an absorbent material suspended in the mixed liquor}
Definition statement
This subclass/group covers:

Using adsorbents or inert solids in suspension in the activated sludge tank, e.g. activated carbon powder or zeolites. The aim of the use of the adsorbents is to adsorb harmful substances or to improve the settleablilty of the flocs rather than to act as a carrier material.

Special rules of classification within this group

This class is not used for classifying fluidised bed reactors. These should be classified in C02F 3/085.

{Small compact installations for use in homes, apartment blocks, hotels or the like}
Definition statement
This subclass/group covers:

Small wastewater treatment plants such as upgraded septic tanks and other compact devices for use in small communities, hotels or single houses.

{Oxidation ditches}
Definition statement
This subclass/group covers:

Extended aeration with simultaneous sludge stabilisation.

{Sequencing batch reactors (SBR)}
Definition statement
This subclass/group covers:

Sequencing batch reactors (SBR) for carrying out several treatment steps batchwise in a single tank.

{Membrane bioreactor systems}
Definition statement
This subclass/group covers:

Membrane bioreactor systems for aerobic treatment of water.

Informative references
Attention is drawn to the following places, which may be of interest for search:
General membrane treatment
Membrane processes
Electrodialysis
Anaerobic membrane treatment
Special rules of classification within this group

If the membrane is used to further purify the wastewater after a clarifier or other liquid-solid separation C02F 1/44 should be used.

{Submerged membrane bioreactors}
Definition statement
This subclass/group covers:

The membrane module is submerged in the activated sludge suspension (treatment tank).

{Mixing devices}
Definition statement
This subclass/group covers:

Mixing devices for keeping the activated sludge suspended.

Informative references
Attention is drawn to the following places, which may be of interest for search:
General mixing
Special rules of classification within this group

Mixing in the context of aeration: C02F 3/14, C02F 3/20 - C02F 3/26.

using surface aeration
Definition statement
This subclass/group covers:

Activated sludge treatment using mechanical surface aeration.

using diffusers
Definition statement
This subclass/group covers:

Aeration in activated sludge processes whereby diffusers are used for aeration.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Dispersing gas in a liquid
using circulation pipes
Definition statement
This subclass/group covers:

Circulation of the activated sludge suspension is achieved by injecting air (mammoth-pump effect).

Informative references
Attention is drawn to the following places, which may be of interest for search:
Dispersing gas in a liquid
{"Deep shaft" processes}
Definition statement
This subclass/group covers:

Processes using very deep treatment tanks for improving oxygen transfer.

Anaerobic digestion processes
Definition statement
This subclass/group covers:

Anaerobic treatment of wastewater.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Anaerobic treatment of sludge
Special rules of classification within this group

Combined aerobic and anaerobic processes (Bio-P removal, nitrogen removal) are classified in C02F 3/30 - C02F 3/308.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Aerobic
presence of dissolved oxygen
Anoxic
oxygen not present as dissolved oxygen but in the form of nitrate, sulfate, etc.
Anaerobic
absence of oxygen
{Anaerobic processes using solid supports for micro-organisms}
Definition statement
This subclass/group covers:

Anaerobic biofilm processes using reactors with fixed beds, fluidised beds or membranes as biomass carrier.

{using anaerobic sequencing batch reactors}
Definition statement
This subclass/group covers:

Biological treatment of water, waste water or sewage with several treatment sets batchwise in a single anaerobic tank

Informative references
Attention is drawn to the following places, which may be of interest for search:
Aerobic SBR processes
{using fluidized bed reactors}
Definition statement
This subclass/group covers:

Biological treatment of water, waste water or sewage by anaerobic digestion processes using a reactor with fluidized bed, the water passing through a granular solid material at high enough velocity to suspend the solid

Informative references
Attention is drawn to the following places, which may be of interest for search:
Aerobic fluidised bed processes
Chemical or physical processes and apparatus conducted in the presence of fluids and solid particles
{using upflow anaerobic sludge blanket (UASB) reactors}
Definition statement
This subclass/group covers:

Reactors containing an anaerobic sludge bed, internal separators and gas collectors.

{using anaerobic membrane bioreactors}
Definition statement
This subclass/group covers:

Membrane bioreactors for anaerobic processes.

Informative references
Attention is drawn to the following places, which may be of interest for search:
General membrane treatment
Membrane processes
Electrodialysis
Membrane bioreactor systems
Submerged membrane bioreactors
{including two or more steps}
Definition statement
This subclass/group covers:

Treatment with two or more anaerobic steps (no oxygen, nitrate, nitrite available).

Informative references
Attention is drawn to the following places, which may be of interest for search:
Aerobic multi-step processes
{with internal draft tube circulation}
Definition statement
This subclass/group covers:

Internal circulation is achieved by the gas bubbles created during the fermentation process (carbon dioxide, methane).

{Two story combinations of the Imhoff tank type}
Definition statement
This subclass/group covers:

Biological treatment of water, waste water or sewage by anaerobic digestion processes with two story septic tank combination, i.e. Imhoff tank: simple reactors, precursors of the UASB reactors.

Aerobic and anaerobic processes
Definition statement
This subclass/group covers:

Processes which are characterised by a combination of anaerobic, anoxic and aerobic process steps, particularly for the biological removal of phosphorous and nitrogen.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Aerobic
presence of dissolved oxygen
Anoxic
oxygen not present as dissolved oxygen but in the form of nitrate, sulfate, etc.
Anaerobic
absence of oxygen
{Aerobic and anaerobic treatment in the same reactor}
Definition statement
This subclass/group covers:

No separate reactors used for the anaerobic, anoxic and aerobic treatment steps.

{Nitrification and denitrification treatment (C02F 3/308 takes precedence ) }
Definition statement
This subclass/group covers:

Biological nitrogen removal by means of combined nitrification / denitrification treatment.

References relevant to classification in this group
This subclass/group does not cover:
Biological phosphorous removal
{characterised by the nitrification}
Definition statement
This subclass/group covers:

Biological nitrification processes, i.e. biological processes for oxidising ammonia to nitrite and/or nitrate.

{characterised by the denitrification}
Definition statement
This subclass/group covers:

Biological denitrification processes, i.e. biological processes for reducing nitrite and nitrate to elementar nitrogen.

{Biological phosphorus removal}
Definition statement
This subclass/group covers:

Biological processes for reducing phosphorous.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Combination of chemical precipitation of phosphorous and activated sludge treatment
{characterised by animals and plants}
Definition statement
This subclass/group covers:

Biological treatment of water, waste water or sewage by using any plants or any animals, e.g. constructed wetlands, worms, algae, protozoa

characterised by the micro-organisms used
Definition statement
This subclass/group covers:

Biological treatment processes using special types of microorganisms (specific species or consortia which are identified and not commonly used).

Informative references
Attention is drawn to the following places, which may be of interest for search:
Biotechnology, micro-organisms in general
{Consortia of bacteria}
Definition statement
This subclass/group covers:

Groups of bacteria which are specified and achieve a synergistic effect.

{characterised by the enzymes used}
Definition statement
This subclass/group covers:

Specific enzymes produced by microorganisms. Also for the use of the pure enzymes.

{characterised by the way or the form in which the microorganisms are added or dosed}
Definition statement
This subclass/group covers:

Dosing of the bacteria in a specific form, e.g. lyophilised, as a powder, together with nutrients) or dosing at a specific location (e.g. in a sidestream).

Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents ( softening using ion-exchange C02F 1/42)
Definition statement
This subclass/group covers:

This group covers processes and apparatus relating to chemical water treatment to prevent clogging or the presence of hard deposits on apparatus in contact with water.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Detergents
Softening using ion-exchange
Softening water by precipitation of the hardness
Definition statement
This subclass/group covers:

This group covers processes and apparatus relating to chemical water treatment to prevent clogging or the presence of hard deposits on apparatus in contact with water, wherein hardness is eliminated by precipitation before it may result in adverse effects.

using phosphates (C02F 5/06 takes precedence )
Definition statement
This subclass/group covers:

This group covers processes and apparatus relating to chemical water treatment to prevent clogging or the presence of hard deposits on apparatus in contact with water, wherein hardness is eliminated by precipitation using phosphates before it may result in adverse effects.

References relevant to classification in this group
This subclass/group does not cover:
Softening using calcium compounds
using calcium compounds
Definition statement
This subclass/group covers:

This group covers processes and apparatus relating to chemical water treatment to prevent clogging or the presence of hard deposits on apparatus in contact with water, wherein hardness is eliminated by precipitation using calcium compounds before it may result in adverse effects.

Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents
Definition statement
This subclass/group covers:

This group covers processes and apparatus relating to chemical water treatment to prevent clogging or the presence of hard deposits on apparatus in contact with water, wherein the adverse effects of hardness are avoided by preventing it to form scale or by removing existing scale.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Use of complexing agents
{Mineral agents}
Definition statement
This subclass/group covers:

This group covers processes and apparatus relating to chemical water treatment to prevent clogging or the presence of hard deposits on apparatus in contact with water, wherein the adverse effects of hardness are avoided by preventing it to form scale or by removing existing scale wherein mineral agents are used.

{Condensed phosphates}
Definition statement
This subclass/group covers:

This group covers processes and apparatus relating to chemical water treatment to prevent clogging or the presence of hard deposits on apparatus in contact with water, wherein the adverse effects of hardness are avoided by preventing it to form scale or by removing existing scale wherein condensed phosphates are used.

using organic substances
Definition statement
This subclass/group covers:

This group covers processes and apparatus relating to chemical water treatment to prevent clogging or the presence of hard deposits on apparatus in contact with water, wherein the adverse effects of hardness are avoided by preventing it to form scale or by removing existing scale wherein organic substances not provided for in the following groups are used.

{combined with inorganic substances}
Definition statement
This subclass/group covers:

This group covers processes and apparatus relating to chemical water treatment to prevent clogging or the presence of hard deposits on apparatus in contact with water, wherein the adverse effects of hardness are avoided by preventing it to form scale or by removing existing scale wherein organic substances not provided for in the following groups are used in combination with inorganic substances.

containing nitrogen (C02F 5/14 takes precedence )
Definition statement
This subclass/group covers:

This group covers processes and apparatus relating to chemical water treatment to prevent clogging or the presence of hard deposits on apparatus in contact with water, wherein the adverse effects of hardness are avoided by preventing it to form scale or by removing existing scale wherein organic substances comprising nitrogen are used.

References relevant to classification in this group
This subclass/group does not cover:
Softening using organic substances containing phosphorous
{combined with inorganic substances}
Definition statement
This subclass/group covers:

This group covers processes and apparatus relating to chemical water treatment to prevent clogging or the presence of hard deposits on apparatus in contact with water, wherein the adverse effects of hardness are avoided by preventing it to form scale or by removing existing scale wherein organic substances comprising nitrogen are used in combination with inorganic substances.

containing phosphorus
Definition statement
This subclass/group covers:

This group covers processes and apparatus relating to chemical water treatment to prevent clogging or the presence of hard deposits on apparatus in contact with water, wherein the adverse effects of hardness are avoided by preventing it to form scale or by removing existing scale wherein organic substances comprising phosphorus are used.

{combined with inorganic substances}
Definition statement
This subclass/group covers:

This group covers processes and apparatus relating to chemical water treatment to prevent clogging or the presence of hard deposits on apparatus in contact with water, wherein the adverse effects of hardness are avoided by preventing it to form scale or by removing existing scale wherein organic substances comprising phosphorus are used in combination with inorganic substances.

Aeration of stretches of water
Definition statement
This subclass/group covers:

Aeration of stretches of natural waters, like rivers, lakes or ponds. Devices for such use such as boats or fixed installations.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Dispersing gas in a liquid
Special rules of classification within this group

Treatment other than aeration should be classified using the relevant classes in combination with C02F 2103/007.

Multistage treatment of water, waste water, or sewage
Definition statement
This subclass/group covers:

This group covers combined treatment operations where the interest is directed to the relationship between the steps. In general at least three different steps should be present

Informative references
Attention is drawn to the following places, which may be of interest for search:
Activated sludge multistep treatment
Anaerobic multistep treatment
Multistage treatment
Special rules of classification within this group

The different steps are classified as additional information in C02F 1/00 to C02F 11/20. For a repetition of the same step C02F 2301/08 can be used, if relevant to the definition of the invention.

{Portable or detachable small-scale multistage treatment devices, e.g. point of use or laboratory water purification systems ( single-stage processes in combination with filtration techniques C02F 1/002 or C02F 1/003) }
Definition statement
This subclass/group covers:

Processes incorporating several treatment steps in a compact, transportable device in the size of a small cupboard, e.g. filter units on wheels, laboratory devices for ultrapure water production, dispensers comprising advanced water treatment.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Small transportable filters
Household type filters
Treatment of sludge; Devices therefor
Definition statement
This subclass/group covers:

In the present context sludge is defined as an aqueous suspension of solids resulting from water treatment processes and having a solids content of more than 0.2% (2 g/L).

{Sludge treatment using liquids immiscible with water}
Definition statement
This subclass/group covers:

Extraction of contaminants from sludge.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Extraction for soil reclamation
{Sludge detoxification}
Definition statement
This subclass/group covers:

Immobilisation or removal of toxic compounds.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Chemical means for combating harmful chemical agents
Chemical reclamation of contaminated soil
{Sludge treatment by fixation or solidification}
Definition statement
This subclass/group covers:

Solidification of the sludge, e.g. by vitrification.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Reclamation of contaminated soil by vitrification
Biological treatment
Definition statement
This subclass/group covers:

Aerobic and anaerobic biological sludge treatment.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Biological reclamation of contaminated soils
Anaerobic treatment; Production of methane by such processes
Definition statement
This subclass/group covers:

Comprises all anaerobic processes for sludge treatment (mostly carried out in digesters).

by oxidation ( incinerators for burning waste liquors, e.g. sulfite liquor from paper-making plant F23G 7/04)
Definition statement
This subclass/group covers:

Oxidation of sludge including thermal oxidation such as incineration.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Incinerators for burning sludge from water treatment installations
Incineration of waste liquors
Wet air oxidation
Definition statement
This subclass/group covers:

Wet air oxidation is defined as oxidation under elevated temperatures and pressure (p >> 100 bar, T >> 100°C).

Special rules of classification within this group

Exceptionally, treatment of wastewater can also be classified here if this is the most appropriate class.

{in the supercritical state}
Definition statement
This subclass/group covers:

The supercritical state for water is defined as p > 221 bar, T > 374°C.

by pyrolysis
Definition statement
This subclass/group covers:

Thermal treatment of sludge under reducing conditions (absence of oxygen or other oxidants).

Informative references
Attention is drawn to the following places, which may be of interest for search:
Destructive distillation of solid carbonaceous materials for production of gas, coke, tar
by de-watering, drying, or thickening
Informative references
Attention is drawn to the following places, which may be of interest for search:
Drying solid materials, granulation
Special rules of classification within this group

Thermal drying is classified in the head group, if the sludge is heated for other purposes, C02F 11/18 and subgroups should be used.

by centrifugation
Definition statement
This subclass/group covers:

Extraction of water from sludge using centrifuges

Informative references
Attention is drawn to the following places, which may be of interest for search:
Centrifuges
Centrifugation of aqueous suspensions
with addition of chemical agents
Definition statement
This subclass/group covers:

De-watering or drying of sludge by drying with chemical agents, e.g flocculants added during or before the dewatering process.

using drying or composting beds
Definition statement
This subclass/group covers:

De-watering or drying of sludge with drying or composting beds, e.g. several drainage layers for the separation of the solid from the liquid fraction of sludge.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Composting of household refuse
by thermal conditioning ( by pyrolysis C02F 11/10)
Definition statement
This subclass/group covers:

Thermal sludge conditioning other than drying.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Thermal conditioning of soil
Sludge treatment by pyrolysis
Special rules of classification within this group

Sludge drying should be classified in C02F 11/12.

{by pasteurisation}
Definition statement
This subclass/group covers:

Sludge disinfection by heating above 60°C.

Nature of the contaminant
Definition statement
This subclass/group covers:

The nature of the contaminant, i.e. chemical composition or class of chemical is specified here.

Nature of the water, waste water, sewage or sludge to be treated
Definition statement
This subclass/group covers:

The nature of the water to be treated such as wastewater from specific origin or pure water for specific applications.

Apparatus for treatment of water, waste water or sewage
Definition statement
This subclass/group covers:

Constructional details related to the apparatus used for water treatment.

Apparatus and plants for the biological treatment of water, waste water or sewage
Definition statement
This subclass/group covers:

Constructional details related to the apparatus used for biological water treatment.

Controlling or monitoring parameters in water treatment
Definition statement
This subclass/group covers:

Controlling or monitoring parameters in water treatment. Details relating to the measuring device and controller used for controlling or monitoring the parameters.

General aspects of water treatment
Definition statement
This subclass/group covers:

General aspects of water treatment, such as fluid flow conditions, e.g. flow arrangements, pressure conditions.

Specific treatment goals
Definition statement
This subclass/group covers:

Specific treatment goals, e.g. disinfection, corrosion inhibition, removal of agents after treatment.

Use of specific compounds during water treatment
Definition statement
This subclass/group covers:

Use of specific compounds in water treatment, e.g. surfactants, nutrients, nanoparticles.

Location of water treatment or water treatment device
Definition statement
This subclass/group covers:

Location of water treatment or water treatment device, e.g. as part of a bottle, pitcher or mounted on a faucet.

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Last Modified: 10/11/2013