Question

explain to your junior five ways in which air can be purified without the aid of man and explain five 5 criteria you will use for the choice of material in large scale purification

Answer 1

Answer :

Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factoriesm , dust pollen and mold spores may be suspended as particles. Ozone, a gas, is a major part of air pollutions in cities. When ozone forms air pollution, it's also called smog.

There is so many ways to pure air pollution such as :

• Using public transport : It is a sure short way of contributing to less air pollution as it provides with less gas and energy, even carpools contribute contribute to it. In addition to less release of fuel and gas.
• Turn off lights when not in use : The enrgy that the lights take also contribute to air pollution, thus less consumption of electricity can save energy. Use energy saving fluorescent lights to help the environment.
• Recycle and Reuse : The concept of recycle and reuse is not just conserve resources and use them judicially but also is helpfull for air pollution as it helps in reducing pollution emissions. The recycled products also take less power to make other products.
• Avoid plastic bags : The use of plastic products could be very harmful to the environement as they take a very long time to decompose, due to their material made up of oil. The use of paper bags instead is a better alternative as they decompose easily and are recyclable.
• Reduction of forest fires and smoking : The collecting of garbage and getting it on fire in dry seasons or dry leaves catching fires is a huge factor for causing air pollution, moreover smoking also causes air pollution and causes the air quality to worsen along with obviously damaging one's health.
• Use of fans instead of Air conditioner : The usage of AC's takes a lot of energy and emits a lot of heat which is bad for the environement. AC's also take a lot of power and enrgy to work as compared to fans.

Water purification :

Water purification is the process of removing udesirable chemicals, biological contaminants, suspended solids, and gasesfrom water. The goal is produce water fit for specific purposes. Most water is is purified and disinfected for human consumption. The methods used include physical processes such as fltration, sedimentation and distillation. Biological process such as slow sand filters or biologically active carbon. Chemical process such as flocculation and chlorination.

There are often seven steps in large scale water treatment.

• Screening  : To protect the main units of treatment plant and to aid in their efficient operation, it is necessory to use screens to remove any large floating and suspended solids thet are present in the inflow. These materials include leaves,twigs, paper rags and other debris that could obstruct flow through the plant or damage equipment.There are coarse and fine screens.
• Aeration : After screening , the water is aerated by passing it over a series of steps so that it takes in oxygen from the air. This helps expel soluble gases such as carbondioxide and hydrogen sulphide, that might given an undesirable taste to the water.
• Coagulation and flocculation : after aeration coagulation takes place. to remove the fine particles that are suspende in the water. In this process a chemical called a coagulantis added to the water, and this neutralisesthe negative electrical charge of the fine particles. In flocculation the water is gently stirred by paddles in a flocculation basin and the flocs come into contsct with each other to form larger flocs.
• Sedimentation : Once larger flocs are formed , they need to be settled out, and this takes place in a process called sedimentation.The water is kept in tank for several hours for sedementation . The material accumulated at the bottom of the tank is called sludge, this is removed for disposal
• Filtration : Filtration is the process where solids are separated from a liquid. In water treatment the solids are not separated out in the sedementation tank are removed by passing the water through beds of sand and gravel.
• Chlorination : After sedementation , the water is disinfected to eliminate pathogenic micro-organism. The most commonly used disinfectant in the form of liquid or a gas. It is relatively cheap, and simple to use. When chlorine is added to water it reacts with any pollutants present, including micro organisms.
• Supplimentary treatment : Supplimentary treatment may sometimes be needed for the benefits of the population. One such instance is the flouridation of water, where fluoride is added to water.It has been started by the World Health Organization that flouridation of water supplies, where possible, is the most effective public health meassure for the prevention of dental decay.