How is the primary treatment to be done?
Pumping – In this process, water is to be pumped out from its source and redirected into pipes or tanks. To remove contaminants from the water, physical infrastructure made of materials is to be set to protect accidental contamination.
Screening – Screening is the first step to purify surface water removing large debris like sticks, leaves and large particles.
Storage – In need of biological purification, water from river needs to be stored for a particular periods that may be in days or few months. This particular treatment becomes very special if the storage water is to be put in storage for a short period.
Pre-conditioning – With this process, hardness in water is to be treated with soda-ash just for good utilizing.
Pre-chlorination – In need of maximum growth of the plants, the incoming water and used water are to be chlorinated through the pipe-work and tanks.
PH adjustment – When the water is acidic, lime or soda is to added with water to rise the PH of the water. As lime is cheaper, it is favourable ultimately. To make the water alkaline, the work of coagulation and flocculation are to be processed. The preparation helps to reduce the risk the trace of lead dissolved in the water.
Coagulation – Coagulation is one of the best purification methods using chemicals such glue, one kind of small particles. The chemical of coagulation is added in a tank with a rotating paddle. The mixture used in the treatment remains into the tank for 30 second maximum. The process of coagulant varies due to different quality source of water.
Flocculation – Flocculation is the process of municipal water treatment with joining of particles in the form of larger settable particles. The large form is called Floc. With this process, coagulants are used and resultant floc is used as filter but sand filters. Unlike the rapid mix tank, flocculation paddles are to be used to turn slowly. Normally, the retention time of basin under flocculation is minimum 30 minutes.
Sedimentation– The water laid in the flocculation basin is to be sent sedimentation basin and this process is also called clarification. Under this process, a large tank is taken with slow flow settled at the bottom. Sedimentation basis comes to be shaped like a rectangle. The clarifier retention time is normally 4 hours. The large basin is to be kept in a shallow basin and there is small particles and small particles to be run. Through these large particles, water comes to filtered for the purification.
Filtration – After separation of floc, the water is to be filtered for final step just to remove suspended particles. Now the common filter is sand filter. Water is to be run through sand with multiple layers. If charcoal is use, then charcoal should be in the top most layers and it removes the taste and smell. To clean the filter, water is passed through the upper portion of the filter and for back washing; the process is to be run properly. Some of the case, plant may be gone through pressure filters. These processes are on the same principles for the gravity filters.
Chlorine – The most general method is the process using chlorine or chlorine dioxide. It is very important to know that chlorine is a strong oxidant which kills organism as chlorine is a toxic gas. The major problem of using chlorine gas or hypochlorite is that both of them react with organic materials in the water. It is good to know that chlorine is effective for killing bacteria but it has limitation to fight against protozoans which is called cysts in water.
SAMR Industries with its technology provides the water treatment services for the good of people in municipality.