Waste water treatment

These techniques, however, are used to treat water. Water contains various colloidal solids such as plankton, decayed plant material, bacteria, clay particles, as well as organic matter. These two processes help to remove these impurities. Coagulation neutralizes the particles and reduces the repelling force. Flocculation agglomerates destabilized atoms to form large particles(Parson and Jefferson, 2006).In the chemical and level theory, flocculation and coagulation involves a three step process that consists of flocculation, flash mixing and coagulation(Akers 1972). For coagulation to take place, flash mixing has to occur. During flash mixing, coagulant chemicals are added to water. This mixture is then mixed violently and quickly distributing the chemicals inside the water. The coagulation-flocculation process destabilizes colloids, removes anions and metals, and removes pathogens as well as inorganic matter. After destabilization, flocs are formed in which particles aggregate come by due to thermal movement of fluid molecules or induction of suspension mix and velocity gradients to be used in sedimentation.Filtration treatments as essential pretreatments are supplemented by coagulation-flocculation processes. These processes accumulate suspended solids and particles into larger bodies to allow easy removal through filtration processes. The removal of particulate matter by these methods tends to supplement the effectiveness of the filtering process. Gravity separation of these suspended solids may also require filtration. In the event of facilitating bonding among various particulates, chemical coagulants such as polymers or iron salts are added to source water(Bratby 2006). The efficiency of this process depends on a number of variables and, therefore, any changes involved may affect other process. Changes may be in form of coagulant feed concentration, final PH, coagulant dosage, type of coagulant used,