PDF | On Jan 23, , Kasun Thivanka Samarasiri and others published Water Purification. At the end of session, the learner shall be able to: courtdadelorec.ga the aim of water purification. courtdadelorec.gabe the purification of water on a large scale. courtdadelorec.gaentiate. e of s used. Water. Purification. Methods. Page 2. 1. 2. 3. How do water-b. X. Risks from drink. 1 Water pollution is usually caused by human and animal.
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water. Water purification generally means freeing water from any kind of impurity it contains such as contaminants or micro organisms. Water purification is the process of removing undesirable chemicals, biological contaminants, Savage, Nora; Mamadou S. Diallo (May ). "Nanomaterials and Water Purification: Opportunities and Challenges" (PDF). J. Nanoparticle Res. There are a variety of techniques available to purify water for the various different uses for . Distillation is a long established technique of water purification.
Upon cooling, vapor is reversed into liquid water that is clean and safe for drinking.
Other substances that have a higher boiling point are left as sediments in the container. This method is effective in removing bacteria, germs, salts and other heavy metals such as lead, mercury and arsenic. Distillation is ideal for people who have access to raw, untreated water.
This method has both advantages and disadvantages. A notable disadvantage is that it is a slow process of water purification. In addition, it requires a heat source for the purification to work. Although cheap sources of energy are being developed, distillation remains a costly process of purifying water.
It is only ideal effective and least costly when purifying small quantities of water It is not ideal for large scale, commercial or industrial purification.
Chlorine is an effective water purification method that kills germs, parasites and other disease-causing organisms found in ground or tap water. Water can be purified using chlorine tablets or liquid chlorine. As an off-the-shelf water purification product, chlorine is cheap and effective.
However, caution should be taken when using chlorine liquid or tablets to treat drinking water. The infiltration technique is chosen according to the hydrogeological conditions, the available ground space, the water need, the composition of the infiltrated water, and the degree of purification to be achieved Schmidt, ; Schmidt and Balke, ; In order to improve the efficiency of natural purification processes in the subsurface, artificial groundwater recharge can be combined with pre-treatment, bank filtration, plant purification, subsurface dams and artificial aquifers Balke et al.
Natural purification processes Surface water contains inorganic and organic compounds of natural origin as suspended matter and dissolved substances. In most cases, water in river and lake is contaminated by waste, sewage, chemicals, hydrocarbons, medicine, hormones, antibiotics, bacteria, viruses, fertilizers, plant-protective agents, etc.
For drinking purposes, the contaminations in water must be removed or destroyed by purifying processes as completely as possible.
Natural purification effects within filter layers and in the subsurface are caused mainly by filtration, sedimentation, precipitation, oxidation-reduction, sorption-desorption, ion-exchange and biodegradation. In plants for artificial groundwater recharge, the water being infiltrated at first passes an artificially installed layer of filter sand. This filter layer retains coarser particles by filtration. Chemical reactions between infiltrated water, solid inorganic and organic substances in the subsurface, and the groundwater flowing towards the extraction well may cause precipitation of sparingly soluble carbonates, hydroxides and sulphides—governed by pH-value and redox-potential—within the filter layer and the aquifer.
The oxygen content of the water is decisive for oxidation processes and activities of microorganisms. The presence of reducing substances such as humic matter, causing a lack of oxygen, is responsible for chemical reductions. Dissolved compounds, among them also contaminants, can be adsorbed especially by clay minerals, iron-hydroxides, amorphous silicic acid, and organic substances. Google Scholar Grimm, N. Surface—subsurface interactions in streams.
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