After cyclones, clean water is hard to find. In addition to bad taste and odor, the contaminated water also contains microorganisms that spread diseases like cholera, dysentery, hepatitis, and typhoid. There are different ways that can be used for purifying the water after cyclones.
In order to avoid consumption of unsafe water, water purification devices are sent by the developed countries as aid to the cyclone hit areas. These purification systems are designed for catering to emergencies.
Portable water purification systems are the ideal way to have clean drinking water at the time of cyclones. These systems do not cost much; some devices can purify around hundred gallons of water. These acceptable methods include techniques like pills and mixes to get pure water.
A combination of water purifying methods is used for supplying uncontaminated water to people. Physical water purification method is concerned with the filtration techniques. These techniques include sand filtration, screens, cross flow filtration and cartridge filtration. Chemical water purification techniques are also used for purifying water with the chemical treatment. Chelating agents are added to the water for reducing its hardness caused due to magnesium and calcium deposits. Oxidizing and reducing agents also help in water purification.
Clarification involves multiple steps to eliminate suspended solids. The process starts with addition of coagulants so that ions can be reduced and accumulate in large particles known as flocs. These flocs settle with the help of gravity in the settling tanks and water is removed from gravity filters. Large particles are easily removed with the help of clarification. Deionization is processed at the time of ion exchange. These exchange systems consists of small beds in the tank. It is treated to absorb certain anions and cations so that they can be replaced by counter ions.
Disinfection is imperative for water purification too. It helps in killing the existing microorganisms present in water. The various disinfection techniques that are used include chlorine disinfection, UV and ozone disinfection. Chlorine has a drawback as it can react with chlorinated hydrocarbons. UV radiation is used a lot these days as exposure to sunlight kills the bacteria and germs present in water.
Apart from chemical and physical water purification techniques, biological methods are also used for lowering organic load of the dissolved compounds. Microorganisms assist in decomposition of compounds. There are two types for biological treatments used for treating the water after cyclones- anaerobic and aerobic treatment. In Aerobic treatment, water is aerated with the help of compressed air while in other system runs on the oxygen free condition.
All the above stated methods are used for water purification after cyclones so people do not have to consume contaminated water and fall sick.