https://www.epo.org/en/node/clean-water

Clean water and sanitation

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These technologies address key aspects of SDG 6 by improving access to clean water, enhancing water quality and promoting the efficient use of water resources. Water treatment technologies - including advanced methods like reverse osmosis, nanofiltration and ultrafiltration - play a vital role in removing contaminants from water, making it safe for human use and preventing diseases. If they are powered by renewable energy, it can further contribute to sustainable water management by reducing reliance on non-renewable energy sources and minimising environmental impact.

Potable water harvesting

The concepts covered in this section deal with the collection of drinking water from a variety of sources, particularly humidity, open bodies of water, rainwater, snow and ice, wells.

Obtaining drinking water from air humidity

Systems for obtaining water from air humidity, making the obtained water drinkable.

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Water intake systems

Methods or installations for obtaining or collecting drinking water from surface water like rivers, ponds, lakes, and the like.

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Obtaining drinking water from seawater: Desalination

Desalination processes are used for removing salts, primarily sodium chloride, from seawater. The processes are mainly based on the use of membranes or thermal separation.

Using membranes

Semipermeable membranes, which allow water to pass through the membrane whilst retaining salts and other contaminants, are commonly used for the desalination of seawater. A pressure difference or concentration gradient is typically used as driving force.

Reverse osmosis

Pressure is applied at the side of the semipermeable membrane receiving the seawater to create a flow of pure water through the membrane.

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Forward osmosis

Instead of applying pressure forward osmosis processes employ a highly concentrated draw solution to create the flow of water through the membrane. 

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Nanofiltration

Nanofiltration is similar to reverse osmosis but applies lower pressures and does not achieve complete desalination.

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Other

Membrane distillation or pervaporation use heat as a driving force.

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Thermal desalination

Pure water is produced by evaporation of the seawater and subsequent condensation.

Using solar energy

Sunlight is employed as heat source for the evaporation.

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Using waste heat

Waste heat from industrial processes or other sources is used for evaporating seawater.

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Other thermal treatment

All other evaporation and condensation processes.

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Electrochemical treatment

An electric potential is created between electrodes and used as a driving force to transfer ions through ion-exchange membranes or onto the surface of the electrodes.

Capacitive deionisation

An electrical potential difference is applied over a plurality of electrodes, which are usually made of a highly porous material and serve to adsorb ions from the water to be purified.

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Electrodeionisation and electrodialysis

Electrodialysis and electrodeionisation devices use stacks of cells comprising electrodes between which ion-exchange membranes are located, creating compartments for producing ion-diluted and ion-concentrated streams.

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Other

All other electrochemical processes used for desalination.

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Other desalination treatment

Processes not mentioned above and including freeze desalination and sorption.  

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Obtaining drinking water using grey water and blackwater

Purification of water from showers, sinks and toilets for reuse.

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Purification of water from rivers or lakes

Processes for removing pollutants and microorganisms from rivers and lakes.

Membrane filtration

Semipermeable membranes, which allow water to pass through the membrane whilst retaining salts and other contaminants, are used for removing pollutants and microorganisms. A pressure difference is employed as driving force.

Reverse osmosis and nanofiltration

Semipermeable membranes comprising pores in the (sub-) nanometer range suitable for removing salts and organic substances.

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Ultrafiltration and microfiltration

Semipermeable membranes comprising micro- or nanometre-size pores for removing microorganisms, small particles and larger organic substances.

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Oxidation

Oxidation processes for breaking down pollutants or disinfection purposes.

Using ozone

Use of ozone (O3) as oxidant.

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Using hydrogene peroxide

Use of hydrogene peroxide (H2O2) as oxidant.

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Ultraviolet radiation

Irradiation with ultraviolet light, having a wavelength of approximately 100 to 400 nm.

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Advanced oxidation processes (AOP)

Combination of ultraviolet irradiation, ozone, hydrogen peroxide or other oxidants to generate highly reactive radicals.  

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Other

Other oxidation processes.

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Sorption using activated carbon 

Removal of pollutants by sorption, with activated carbon and similar carbon based sorbents.  

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Rainwater harvesting

Methods or installations for obtaining or collecting drinking water from rainwater.

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Obtaining drinking water from snow or ice

Methods or installations for obtaining or collecting drinking water from snow or ice.

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Maintaining condition of wells

Keeping wells in good condition, e.g. by cleaning, repairing, regenerating, as well as maintaining or enlarging the capacity of wells or water-bearing layers.

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Water wells

Methods or installations for obtaining and confining drinking water by means of wells.

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Wastewater and sludge treatment

This technology field includes the areas of biological wastewater treatment, centralised, decentralised and/or in batch technology. Within it, an important area of biological wastewater treatment is the advanced removal of phosphorus and nitrogen. It also includes utilisation/valorisation of the biogas produced and the biological, mechanical and/or thermal treatment of the sludge produced.

Further, it refers to tertiary wastewater treatment, which includes disinfection and removal of endocrine disrupters, PFAS, pharmaceuticals, and other pollutants.

Biological wastewater treatment

This field includes biological wastewater treatment, which can be centralised, decentralised or operated in batch processes. A critical area within biological wastewater treatment is the advanced removal of phosphorus and nitrogen, essential for preventing eutrophication and maintaining water quality. Additionally, the field involves the utilisation and valorisation of biogas produced during the treatment process, converting it into energy or other valuable products.

Compact devices for decentralised treatment

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

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Membrane bioreactors

Membrane bioreactors are systems for aerobic and anaerobic treatment of water, whereby the membrane module may be submerged in the activated sludge suspension (treatment tank).

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Sequencing batch reactors

Sequencing batch reactors are biological treatment reactors for carrying out several treatment steps batchwise in a single tank (fill, react, settle, decant).

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Advanced nitrogen and phosphorous removal (nitrification, denitrification, anammox)

Advanced nitrogen and phosphorous removal processes are biological processes removing nitrogen, phosphorous or both by aerobic, anaerobic or anoxic processes or combinations thereof.

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Production and valorisation of biogas

Anaerobic wastewater treatment processes produce biogas that can be captured and used for other goals.

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Sludge treatment

The treatment of sludge, which is a byproduct of wastewater treatment, involves biological, mechanical and thermal methods to reduce its volume and potential environmental impact, either by making the sludge suitable for disposal, or by making valuable products from it.

Biological treatment (composting, digesting and fermentation)

Biological treatment includes all aerobic and anaerobic biological sludge treatment processes.

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Dewatering and drying

Dewatering and drying includes all processes removing of water from sludge produced during biological wastewater treatment.

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Thermal treatment

Thermal treatment includes all processes using heat to transform wastewater sludge (thermal drying, pyrolysis, wet air oxidation, thermal conditioning, pasteurisation and hydrothermal carbonisation).

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Valorisation

Valorisation processes are processes in which useful products are obtained from wastewater sludge (fertilisers, concrete additives, etc.).

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Tertiary (advanced) wastewater treatment

Tertiary wastewater treatment focuses on disinfection and the removal of contaminants of emerging concern, such as endocrine disruptors, per- and polyfluoroalkyl substances (PFAS), and pharmaceuticals, ensuring that the treated water is safe for discharge or reuse.

Disinfection through ultraviolet radiation

Ultraviolet water treatment processes use light having a wavelength of approximately 100-400nm.

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Filtration processes

In water filtration processes substances are physically removed from water

Membrane filtration by reverse osmosis

When applying reverse osmosis, water is forced by applying external pressure to pass a semi-permeable membrane having pores of about 1 nanometer

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Membrane filtration by nanofiltration

In nanofiltration processes water is passed through a semi-permeable membrane having pores of about 1-10 nanometre.

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Membrane filtration by microfiltration

In microfiltration processes water is passed through a semi-permeable membrane having pores of about 0.1 -10 micrometre.

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Membrane filtration by large scale filtration

Large scale filtration implies the passing of large quantities of industrially produced wastewater through a grid to remove solid substances. Large scale filtration is usually a first treatment step in a multistep treatment.

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Others

All other types of filtering

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Removal of micropollutants

Micropollutants are persistent organic pollutants present in small quantities.  These components include amongst others detergents, endocrine disruptive agents, pesticides, polyaromatic hydrocarbons and organohalogens such as PFAS.

Oxidation processes

Oxidation processes are processes that chemically break down the micropollutant into one or more harmless products in the present of a strong oxidant such as ozone or hydrogen peroxide.   

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Using sorption

Sorption processes are processes where the micropollutant is captured on a generally solid sorbent.  The micropollutant can be captured in different ways, e.g. by chemisorption or by complexation. 

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Efficient water treatment

“Efficient water treatment” relates to the use of renewable energy sources as power supply for water treatment processes, to energy-efficient processes for water treatment, or to the optimisation of water treatment processes using advanced control strategies and data analysis.

This includes for example the use of photovoltaic modules or wind turbines as autonomous power supply for mobile water treatment installations. Such mobile water treatment installations could be used for purifying wastewater or for producing potable water from seawater and would typically be mounted on a trailer, vessel or barge.

Energy recovery refers to applications where energy employed for treating water is recovered, such as pressure recovery devices in reverse osmosis.

The optimisation of water treatment processes using advanced control strategies and data analysis is also covered, and includes the use of artificial intelligence, neural networks, etc. for more efficiently automatizing and controlling water treatment processes.

Renewable energy sources and energy efficiency

Use of renewable energy sources as power supply for water treatment, in particular for mobile applications, such as portable devices.

Use of solar energy; photovoltaics

Solar energy is employed to produce electricity, for example with photovoltaic panels.

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Use of wind energy

Wind energy is employed to generate electricity, for example with wind turbines.

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Use of wave energy

Wave energy generators for producing electricity.

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Hydroelectric energy

Hydroelectric power supply, such as turbines.

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Energy recovery

Recovering energy from water treatment processes.

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Technology related to automatization and control

Control processes specific to water treatment.

Artificial intelligence, neural networks, algorithms, internet of things

Use of artificial intelligence, machine learning, special algorithms for controlling water treatment processes.

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Conventional control and automation technology

All other control technologies employed to automatize water treatment processes.

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Other technologies

This technology field encompasses methods and equipment designed to prevent and clean up oil spills and microplastics, ensuring the protection of aquatic environments.

Prevention or mitigation of surface water contamination

Natural waters such as rivers, lakes, seas and oceans are vulnerable.  Protecting them can be done either by preventing unwanted substances to enter the water body or the remove unwanted substances from the water body.

Prevention and removal of oil spills

Oils spills do not include only spills from oil but spills from all fatty or oily substances or similar floating materials.  They can be removed using a wide variety of devices (e.g. grease traps, oil water separators, oil skimmers).

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Prevention and removal of microplastics

Microplastics are plastic particles of less than 5mm. They originate from a variety of sources including cosmetics, clothing and food packaging.    

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Prevention of algae growth

Avoiding the excessive growth of algae is crucial to keep an ecosystem in optimal shape.  When present in too high concentrations, algae block sunlight from reaching other organisms, cause depletion of oxygen level in the water and may injure biological life by excreting toxins.

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Ballast water treatment

Treatment of ballast water or bilge water originating from marine vessel, ships, and boats.  The treatment is particularly applied to avoid the spreading of invasive exotic species.

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Water conservation; Efficient water supply and use

This includes water-saving solutions in water use, such as efficient irrigation methods and devices, as well as smart solutions for controlled irrigation in agriculture and in small and municipal structures.

It also includes water-saving measures in everyday use, i.e. sanitary water use.

However, protection of water resources is also considered, e.g. protection of rivers, installation of saltwater barriers and protection of water reservoirs through leakage reduction and detection.

Efficient irrigation / watering

Covering controlled irrigation for agriculture and municipal use.

Watering arrangements - cultivation in receptacles, forcing-frames or greenhouses

Irrigation in closed cultivation structures in contrast to open fields.

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Watering gardens, fields, sports grounds or the like - limited to drip, sprinkler, or spray irrigation

Watering arrangements in built-up environments…

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Control of watering – open-field irrigation

Controlled irrigation in agricultural settings, i.e. fields.

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Leakage reduction or detection

Leak reduction or detection is extended to pipeline components wherein bursting of pipes by freezing is prevented; to tank arrangements for water supply; to hydrants; and to supply pipe systems.

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Protecting water resources

Before having to protect from or mitigate water pollution, it is essential to invest in the protection of aquatic environments at the source.  The following queries explore ways to accomplish this.

River restoration

Protection and restoration of rivers and riverbanks.

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Saltwater intrusion barriers

Processes and systems aimed at monitoring and preventing intrusion of salt (sea) water into fresh water.

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Aquifer recharge

Groundwater or undergound water is artificially enriched by adding water thereto.

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Measures against unauthorised use of potable water resources

Hydrants and pumping plants in wells including means for protecting against e.g. vandalism or sabotage.

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Water saving techniques at user level

Not only the water providers need to innovate, water saving starts at the level of the individual user.  Here, the platform queries provide insight into what technologies for water saving exist at the end of those who use water – every consumer.

Recirculation of potable water having left the tap

Potable water which has left the tap but still has the potable water quality is reused or recirculated.

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Recirculation of potable water before leaving the tap

Potable water is circulated (in a safe environment) before it leaved the tap in order not to waste warm water “not warm enough” before the warm water reaches the correct warm water temperature.

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Water-saving in faucets

Faucets are provided with an aerator in order to feed air into flow of water which reduces the water volume used as such. Also means for reducing water pressure, flow reducers and anti-dripping devices are included.

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Water-saving in toilet cisterns

Likewise, water can be efficiently saved where we hardly notice it – in toilets.

Dual flush valves in toilet cistern

Users can save water by utilising flush valves allowing flushing of two or more different volumes of water.

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“Ultra-low” flushing

Even more flush water can be saved by using special flushing systems using up to 4L flush water, sometimes referred to as ultra-low flushing.

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Using greywater

Similarly, lightly polluted water from household use can be reused for purposes other than drinking, as it is of lower purity, but still perfectly usable.

Using household water from wash basins and showers

Systems reusing and/or recirculating greywater originating from household appliances.

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Using rainwater

Systems reusing and/or recirculating greywater originating from rainwater.

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Greywater used for flushing toilets

Systems using greywater, originating from household or rainwater, for flushing toilets.

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Other aspects, e.g. heating

Systems recovering energy from (still warm) greywater, e.g. from shower water.

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