JAM Classes

  Composition of Soil Soil According to Soil Science Society of America, soil is defined as the unconsolidated mineral or organic matter on the immediate surface of the earth that serve as a natural medium for the growth of land plants. Composition of soil As far as the composition of the soil is concerned it is composed of four basic components: Minerals-           45% Organic matter 5% Water-               20-30 % Air-                   20-30% The amount of these components of the soil depends on the quality of vegetation, soil compaction and water present in the soil. But in reality the composition is very much complex and is dynamic in nature. The above four components are categorized under two headings solid phase and non-solid phase. Solid phase includes mi...

  Wastewater Treatment The water that has been used in various activities is termed as wastewater. It must be treated before its discharge into the environment. There are several stages of wastewater treatment. Wastewater treatment plants use primary, secondary and tertiary stages. 1.Primary treatment In this step waste water treatment primary treatment involves a number of physical process these include Screening In this process bar screens with 10 millimeters mesh size are used to block the flow of large floating debris like plastic cans, wrappers, wood pieces etc. so that they don’t enter into the next unit as these large debris may hinder the function of machinery to a great extent. Comminution In this process a comminutor is used to grind the debris that pass through the bar screen later on these grinded residue is removed by sedimentation. Grit removal In this physical process a large narrow tank is used to slow down the flow of incoming wastewater so th...

  Marine Pollution The change in the physical chemical and biological properties of sea water upon the addition of toxic pollutants from a variety of source either intentionally or unintentionally which can have a devastating impact particularly on marine biodiversity is referred to as marine pollution. According to UN the introduction by man directly or indirectly of substances or energy to the marine environment resulting in deleterious effects such as: hazard to human health, hindrance to marine activities impairment of the quality of seawater for various uses and reduction of amenities. Types of marine pollution The circle of marine pollution is quite vast which encompass many types of pollution which have an adverse effect on marine ecosystem. these are: Chemicals Light Noise plastic pollution Sources of marine pollution 1. Domestic Sewage The sewage disposal into rivers lakes etc. ultimately reach the marine ecosystem it contains a variety of pathoge...

    Previous Year Question Papers of Jammu and Kashmir State Board of School Education ENVIRONMENTAL SCIENCE CLASS:  12th            Year  2018   Time: 3 Hours                Maximum Marks: 70                       Long Answer Type   Questions                                                   (5   Marks Each) 1. Define air pollution . Describe any four sources of air pollution. Or  Describe very briefly any five measures taken by Govt. of India in controlling air     pollution 2. Write a detailed note on survivorship curves. Or Define population dynamics. Explain any four factors which affect population and its growth. 3. Define ecosystem stability and write a deta...

  Control of water pollution Water is one of the precious resource but in the present scenario this resource is under great threat and become a matter of great concern throughout the globe. Humans have polluted the water resources beyond expectation if this will continue and if no royal step is taken, no doubt in the near feature this problem become even worse this will not affect the humans but all other living creatures which finally create an ecological imbalance. Keeping this in view control of water pollution should be on the top of our priorities. As we know that sources of water pollution come from two sources point and non-point source. the former can be controlled easily whereas latter one is bit difficult. Control of the point source pollutants should be achieved by adopting the procedure of end of pipe controls and process control. Following control measures should be taken into consideration Domestic waste should not be thrown directly into water bodies. Domestic se...