4. CHAPTER-2 4.0 LITERATURE REVIEW 4.1 Resources and Need for Water Desalination The earth contains about 1.4×10⁹ km³ of water, which covers approximately 70% of the planet surface area; the percentage of salt water in this large amount is 97.5%. The remaining 2.5% is fresh water with 80% of this amount frozen in the icecaps or combined as soil moisture. Both forms are not easily accessible for human use. The remaining quantity, about 0.5%, is believed to be adequate to support all life on Earth.
Moreover it’s not hard to find proofs of the impact of cleaning supplies to natural environment, it is enough to go to holidays to a lake. Most of the lakes are muddy, full of plants and with minimal amount of the fishes. It is a proof of negative impact cleaning products everyone have probably seen. But it is important to remember that everyday millions of square meters are cleaned and it requires with it usage of the cleaning products. Only in the United States of America every year commercial and institutional buildings consume 6.2 billion pounds of chemicals, 4.5 billion pounds of sanitary paper (about 30 million trees), and 1 billion pounds of janitorial equipment.
Therefore not all countries in this world will be able to afford or product desalination plants. Another disadvantage are the environmental impacts the desalination plants make. Removing the salt removed from the water is a big issue. The discharge which is also known as brine, lowers the amount of oxygen in the water at the disposal site, which leads to the killing of animals that are not used to the higher levels of salt. In addition, the desalination process uses numerous chemicals including chlorine, carbon dioxide,
In concluding, there have many reasons that make water become polluted such as oil spill, plastic garbage or sewage. Water pollution also causes many problems with the living plants and animals in the water. Many countries have laws to protect the environment and limit water pollution, but that is not enough to solve the many problems. People living on this planet have to be responsible and get involved in keeping our water supply fresh and clean. Everyone needs to be more concerned with our water supply and products that can threaten it.
Many factors cause water pollution to occur and increase over the years. The most important thing uses to cause water pollution is sewage pollution of boundary waters. Sewage mentions to fluid wastes containing a combination of human feces and wastewater from non-industrial human hobbies such as soaking, washing, and cleaning. In countless poor areas of the world, sewage is dumped into innate waterways, in the nonexistence of useful alternatives. Untreated sewage poses a main risk to human condition as it contains waterborne pathogens
Water is one of the most important and vital substance on earth. All life forms on earth require water to survive. If there will be no water there would be no life on earth. Aside from drinking water to survive, people have many other uses for water. An organism which does not require water is never discovered.
Water pollution is the contamination of water due to unhealthy human activities. The pollution is mostly caused by industrial waste, global warming, garbage and waste dumping, and oil leakage. According to waterbenefitshealth there are many types of water pollution such as “Surface water pollution, Groundwater pollution, Microbial pollution, Oxygen Depletion pollution, Nutrient pollution, Suspended Matter pollution, and Chemical pollution.” Water pollution is a hazardous case in the world as it leads to hunger, poverty, diseases, extinction of aquatic animals, and lack of human access to fresh water.
The activity of solid waste disposal in open un-engineered landfill is the one of the factor that cause the ground water pollution due to lack of pollution control interventions such as water proof layer, leachate treatment pond, monitoring wells etc. (Mohamad et al., 2007). Groundwater pollution also occurs due to clandestine disposal of toxic wastes, especially from industrial sites, or undetected leakage from pipes, waste storage containers, or underground tanks. According to WHO organization, about 80% of all the diseases in human beings are caused by water. Once the groundwater is contaminated, its restoration to actual condition requires prolonged time and decontamination is not possible by just stopping the ingress of pollutants from the
Most of it is caused by urban areas and humans. This pollution cause many people to become ill and some even die. Also plants and animal life suffer and ecosystems deteriorate. “South Africa has, in general, a limited supply of water and the quality of this water is being threatened by pollution and the destruction of river catchments. Water is a vital resource and it is up to ALL South Africans to act responsibly in their daily lives and look after the available water resources to ensure that this limited supply is usable by all life on earth.” (Team, n.d.) Causes of pollution: (Team, n.d.) • Urbanisation – ineffective sewage collection and treatment, physical disturbance of land and increase in litter.
Pollution of surface water has become a global concern. Surface water resources played an important role in the development of human civilization. In developing countries there is lack of adequate infrastructure and facilities,so the major part of the liquid waste is disposed offin the surface water bodies .In India the total wastewater is generated about 22,900 million liters per day (mld) from the urban domestic sources, only the treatment of 5900 mld are done and rest remains untreated.The rivers of India are heavily polluted and its endangering the existence of aquatic life. The polluted surface water adversely affecting the ecological health of the aquatic system, when organic matterdegradesit reduces the dissolved oxygen in water resulting in anoxic conditions.The organic pollution level in an aquatic ecosystem is measured by biochemical oxygen demand (BOD) and dissolved oxygen (DO) .In an aquatic system, the BOD is the primary parameter needed for assessment of water quality and the same is used for the development of the management strategies for the safeguarding the water resources.The available method for BOD determination is very tedious and prone to errors [3-5]. The BOD determinationis affected by various factors, like presence of toxic substances in sample affects microbial activity leading to a reduction in the measured BOD value.