Domestic water treatment Prof.Madi Al-Jaghabir

Water treatment Water treatment is any process that makes water more acceptable for a specific end-use, it removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use such as ( drinking, industrial water supply, irrigation water recreation or many other uses, including being safely returned to the environment)

Substances that are removed during the process of drinking water treatment include:  suspended solid bacteria Algae Viruses fungi minerals such as iron and manganese . 

Measures taken to ensure water quality not only relate to the treatment of the water, but to its conveyance and distribution after treatment. It is therefore common practice to keep residual disinfectants in the treated water to kill bacteriological contamination during distribution.

Treatment technologies A variety of candidate technologies for treatment of household water have been described and many are widely used in different parts of the world. The technologies to improve the microbial quality of household water and reduce waterborne disease include a number of physical and chemical treatment methods. The physical methods include : boiling heating (fuel and solar), Settling Filtering exposing to the UV radiation in sunlight, and UV disinfection with lamps.

Physical methods Filtering Heating Fuel or solar

Water treatment by exposing to UV radiation in sun light Solar disinfection Ultraviolet radiation from the sun will destroy most pathogens, and increasing the temperature of the water enhances the effectiveness of the radiation. In tropical areas, most pathogens can be killed by exposing the contaminated water to sun for five hours, centered around mid day.

Water treatment by exposing to the UV radiation in sunlight

Water treatment by UV disinfection with lamp

coagulation-flocculation and settlement ion exchange -The chemical methods include : coagulation-flocculation and settlement ion exchange chemical disinfection with germicidal agents (primarily chlorine).

Coagulation, flocculation& settlement Coagulation, flocculation and settlement In coagulation, a liquid coagulant, such as aluminum sulfate, is added to the water to attract suspended particles. The water is then gently stirred to allow the particles to come together and form larger particles (flocculation), which can then be removed by sedimentation, settlement or filtration. The amount of coagulant needed will depend on the nature of the contaminating chemical compounds and solids.

Coagulation, flocculation& settlement

Water treatment by ion exchange method. Ion exchange softening, passes water through a filter containing resin granules. In the filter, known as a softener, calcium and magnesium in the water are exchanged for sodium from the resin granules. The resulting water has a hardness of 0 mg/L .

Chlorination of water at household level can be used as an emergency measure or as part of everyday life. When water quality cannot be trusted, a carefully measured amount of concentrated chlorine solution is added to a container with a known amount of clear water. The mixture is stirred and left for at least 30 minutes, to let the chlorine react and oxidize any organic matter in the water. After this, the water is safe to drink. The amount of chlorine needed depends mainly on the concentration of organic matter in the water and has to be determined for each situation. After 30 minutes, the residual concentration of active chlorine in the water should be between 0.2–0.5 mg/l, which can be determined using a special test kit.

Some water treatment and storage systems use chemicals and other media and materials that can not be easily obtained locally at reasonable cost and require relatively complex and expensive systems and procedures to treat the water. Such systems may be too inaccessible, complex and expensive to employ for treatment and storage of household water in some places and settings.

Water treatment can be done At : House hold level Water distribution Bottled water Mineral water Municipal water

Household water-treatment systems: Boiling Filtering domestic chlorination

Water treatment at distribution system The purpose of distribution system is to deliver water to consumer with appropriate quality , quantity and pressure . Distribution system is used to describe collectively the facilities used to supply water from its point source to the usage .

Bottled water/ Packaged Drinking Water is drinking water (e. g Bottled water/ Packaged Drinking Water is drinking water (e.g. well water, distilled water, also mineral water or spring water etc.) packaged in plastic or glass water bottles that may be carbonated or not.

Bottled water must be tested and meet regulatory standards before it can be sold . Most bottled water comes from a ground water source, where water quality varies less from day to day and typically less vulnerable to contamination than water from surface sources. However, ground water can still contain naturally high amounts of certain contaminants, including radioactive elements, arsenic, and nitrates

Moreover, some bottled water comes from surface water sources. Bottled water from a surface source or plant may have a more consistent taster than tap water. Public water system that use surface water sources typically receives additional treatment, such as filtration and disinfection. If bottled water is fluoridated due to the source of public water system or naturally occurring fluoride, it must indicate on the label .

The key taste difference between tap water and bottled water is due to how the water is disinfected. Tap water may be disinfected with chlorine, chloramines, ozone, or ultraviolet light to kill disease-causing germs. Water systems use these disinfectants chlorine and chloramines because they are effective and inexpensive, and they continue to disinfect as water travels through pipes to homes .

Bottled water that is disinfected is typically disinfected using ozone or other technologies such as ultraviolet light or chlorine dioxide. Bottlers prefer ozone, though it is more expensive than chlorine, it does not leave a taste. And, bottlers do not need to worry about maintaining disinfectant in water sealed in a container. Ozonation- water is disinfected using ozone, which kills most microbes, depending on dosage applied.

Mineral water is water containing minerals or other dissolved substances that alter its taste or give it therapeutic value, Such as Salts, sulfur compounds, and gases are among the substances that can be dissolved in the water. Mineral water can often be effervescent. Mineral water can be prepared or can occur naturally.

bottled water may be called mineral water when it is bottled at the source and has undergone no or minimal treatment. Permitted is the removal of iron , manganese, sulfur & arsenic through filtration or treatment with ozone- enriched air , in so far as this treatment doesn't alter the composition of the water as regards the essential constituents which give it its prosperities.

No additions are permitted except for carbon dioxide, which may be added, removed or re-introduced by exclusively physical methods. No disinfection treatment is permitted, nor is the addition of any bacteriostatic agents.

A combination selected from the following processes is used for municipal drinking water treatment worldwide: Pre-Chlorination for algae control and arresting biological growth Aeration along with pre-chlorination for removal of dissolved iron when present with small amounts relatively of manganese Coagulation for flocculation or slow-sand filtration Sedimentation for solids separation that is removal of suspended solids. Filtration to remove particles from water either by passage through a sand bed that can be washed and reused or by passage through a purpose designed filter that may be washable. Disinfection for killing bacteria viruses and other pathogens.

Refrences http://www.who.int/household_water/research/technologies_intro/en/ http://www.who.int/water_sanitation_health/hygiene/om/linkingchap6.pdf https://en.wikipedia.org/wiki/Water_supply_and_sanitation_in_Jordan