Generally, water has numerous purposes: drinking; bathing; washing clothes and dishes; cooking; flushing toilet, irrigation, just to name a few. Its significance cannot be over stressed. This is on the grounds that every day each individual uses water for one thing or the other.

As water flows throughout the distribution system, microorganisms can contaminate the flow of water through the pipes, air valves, pump boosters, network of piping system and sometimes through the plumbing system.

Inability to attain a water quality as high as feasible can open individuals to the risk of getting diseases that can easily be avoided through percussive methods.

Drinking and domestic use

Household or domestic water is mainly the water used for drinking, washing and cleaning purposes. Water quality hence is dependent on its micro-constituents and whether or not it has adverse effects on consumption. Therefore, water containing harmful or toxic microorganisms and elements is regarded as unfit for household consumption. Basic examples of toxins found in household water incorporate microorganisms, for example, protozoa viruses, and bacteria; inorganic contaminants, for example, salts, metals, radioactive contaminants and small amounts of organic contaminants.

However, industrial water includes water sources used mainly for industrial purposes. The quality of water in this scenario is therefore slightly different than the water meant for consumption purposes. For instance, hard water, which constitutes

high concentrations of minerals, hampers the effectiveness of soaps or detergents whereas drinking water should most preferably be hard water because of the presence of ions such as calcium and magnesium.

On the other hand, environmental water describes water available to the biosphere and which in some way affects the balance of the ecosystem. Lethal constituents and high masses of specific microorganisms pose risks for non-drinking purposes, for example, swimming and irrigation which inhabits the use of domestic water. The measured quality of water bodies is called Ambient Water Quality.

Importance of good water supply

The quality of water is noted as important not only because it affects health, but also because it has the tendency to improve it as well. The body is made up of 70% water and the amounts of magnesium and calcium present in any body of consumable water has the ability to improve bone mass and density.

The elements present in water, depending on their quantities, have the ability to hamper the effectiveness of industrial machines by causing rust, brittleness, clogging, bursting, etc. Hence, to ensure the a good standard water quality, there needs to be an understanding of what pollutants and contaminants upset the balance of water constituents is necessary to ensure that balance is not tempered with.

Trace levels of ammonia, barium, lead, copper, nitrites, radium, selenium, etc. have negative effects on humans if present in large amounts and can only be curtailed via treatment. There is the point-of-use treatment which involves the treatment of water at the point of consumption using methods such as reverse osmosis, ultraviolet technologies and distillation. On the other hand, point-of-entry

involves the treatment of water needed for household chores using methods such as ion replacement and filtration. On the line of water distribution or supply, filtration comes as it is a key process in ensuring good water quality.

Description of the purification methods

Physical Form of Water Purification: It is thus named because it is concerned with filtration techniques. Filtration is used while purifying water because it effectively rids the said portion of water of particles, silts or debris. Sometimes, for special purposes, specific filters capable of filtering out bacterial form can be engaged. A few examples of physical purification include:

  1. Screen: Usually used to remove large contaminants like leaves and twigs.
  • Sand Filtration: It is a vigorous process used to remove suspended solids from water. It consists mainly of a filter medium containing multiple sand layers of different sizes and densities. These solids are precipitated as residue when water is made to flow through the filter. Because smaller solids have the ability to pass through sand filters, they are subjected to a secondary filtration.
  • Cross Flow Filtration: This is a filtration concerned with using a permeable membrane to remove both salts and dissolved organic matter that only permeates the contaminants. The filtrate is removed as the process goes on. The following are types of cross flow filtration: micro-filtration, ultra- filtration and reversed osmosis.
  • Cartridge Filtration: It generally operates effectively and economically on applications having excessively high contamination levels. They consist of fibers and are normally used as final processes as polishing filters.

Chemical Form of Water Purification

  1. Chemical Addition: This process mainly consists of agents such as chelating, oxidizing and reducing agents. They are necessary to add to the water to prevent the negative effects of hardness, caused by the deposition of elements
  2. Clarification: It consists of a series of processes that involves the addition of coagulants to remove large. Suspended solids. Coagulants help to reduce the charges of ions causing the particles to gather and form larger particles called Flocs. These particles are removed as water flows. Further treatment may be needed because the water may still contain some suspended solids.
  3. Deionization and Softening: This is commonly processed through a system called Ion Exchange. It consists of a tank of synthetic resin which is treated to selectively absorb certain cations or anions and replace them with desirable counter-ions until all the available spaces are filled up with ions.
  4. Disinfection: Disinfection is one of the most important and widely known steps in the purification of water for household use. Often referred to as biocides, they serve the purpose of killing undesired microorganisms in the water; ozone, chlorine and controlled UV-radiation disinfections are good examples.
  5. Distillation: Distillation is the collection of water vapor, after boiling.

Because most contaminants do not vaporize, with a properly designed system, the remaining organic and inorganic contaminants and biological impurities can be obtained.

  • Electro dialysis: Electro dialysis is a complex technique which employs the use of electrical currents and special membranes – membranes which are semi permeable to ions based on their charge. Those membranes that

permeate cations and anions are placed alternately with electrodes on each side and flow channels between them. The electrodes draw their counter ions through the membranes, so that these are removed from the water.

Sometimes, the water in cities are pH adjusted to prevent corrosion from pipes and to prevent the dissolution of lead into the water supplies.

Biological Water Purification

Biological water purification is a process undertaken to lower the load [The Biological Oxygen Demand (BOD)] of dissolved organic compounds using Microorganisms such as bacteria to decompose these compounds. There are two main categories of biological treatment: aerobic treatment where the water is aerated with oxygen and anaerobic treatment which runs under oxygen free conditions.

Water safety and quality

Water is one of the key fundamental supplements required by the body in sufficient amount in other for authentic human functioning. It is not produced by the body. It constitutes some amount of the body fluid, for example: sweat, urine, blood, saliva, just to name a few. Then again, it can be acquired from the ingestion of food and fruits.

The nature of water ought to be free from high concentrations of any pathogenic microorganism that can result in an ailment on intake. Pathogenic microorganisms can be evident but should not be present in concentrations that can result in disruption of the body on intake. Throughout the years, there has been much discussion over the satisfactory concentration of pathogenic microorganisms in

water. Be that as it may, the United States Environmental Policy Agency (USEPA) worked up an adequate concentration level that is renowned around the world.

Around the world, diverse health organizations have set principles for water quality. Out of the different sorts of water sources, water taken into the body ought not to contain microorganisms like bacteria, and should have a low concentration of dangerous chemicals (that is, chemicals toxic to humans). The presence of these microbes in water are evident in nature and testing for specific bacteria can be time consuming. This is why it is better to use indicator organisms to check if coliforms exist in water distribution systems.

Water quality is a term most adequately used to insinuate the substance, physical, organic, and radiological characteristics of water. It should measure the condition of water bodies in respect to the requirements of one or more life structures and to any human need. Regularly, the most broadly perceived benchmarks used to assess water quality relate to wellbeing and the security of human contact and drinking water. Therefore, the nature of desired water quality fluctuates with intended usage.

Faults in the system

The following is a list of reasons for water pollution:

  • Untreated water from motorways and cleared surfaces when it rains runs-off conveying sediments, lethal chemicals from the engine of vehicles, pesticides and composts from gardens, pathogens and microscopic organisms like bacteria from pet waste and broken septic tanks into nearby water bodies.
  • The increase of nutrients leads to large algal blooms which eventually leads to reduced amounts of dissolved oxygen in the water after the death and decomposition of these algae creating hypoxic or “dead zones,” in which organisms cannot survive.
  • Also wastes that are not appropriately discarded wash into drains or get blown into waterways and turn into debris.



Contamination of water by disease causing and non-causing organisms happens mainly from the source where water is obtained, although it can also arise during water treatment or within the distribution system. Contamination may also arise due to some environmental factors.

One of the significant water pollution issues seen to be prevalent is the exposure to transmittable diseases through water that is contaminated with mammal waste. Water-borne related diseases usually arise from the use of water that has both been treated but there is a problem with the efficacy of the process and generally water that has not gone through any treatment processes. Flushing out the water distribution system really helps in reducing the risk of getting water borne related diseases.

Furthermore, the inclusion of filters at different points in the water distribution system helps in the reduction and finally elimination. As a result if this, the probability of water-borne related diseases occurring is reduced because the

filters filtrate both pathogenic and non-pathogenic organisms and ensure the cleanness of water quality.

Water pathogens such as Giardia and Salmonella can be introduced in as a result of periodic habitation of domestic animals. These animals that live near water areas are known reserves for these intestinal pathogens and are causative agents of water uncleanness.