Currently, coagulation operation is one of the most important units of water treatment and frequently is a necessary unit which cannot be omitted or substituted. The targets of coagulation are the colloidal and suspended particles which consist of insoluble and hydrophobic materials. Therefore, the attempt to remove soluble materials from water by coagulation directly is impracticable. If some soluble materials can be transformed to insoluble materials, they will be coagulated. In some cases, soluble materials can be removed to some extent since they are adsorbed onto the flocculates formed in the coagulation process; as a result,

the co-precipitation will take place, which can be considered to be a synergy effect. Generally, the flocculates produced can be separated from water by settling, filtration, flotation, etc. The purpose of coagulation is not only to cause particle settling but also to give particles the appropriate surface property which facilitate particles to be retained by the filter medium in subsequent filtration unit. The aim of water treatment for the water supply is to provide drinking water for people and industrial water for production. In water plants for the water supply, surface water or underground water is treated to meet the standards of usage by people or the industry. The typical technological process includes natural sedimentation, coagulation, sedimentation, filtration, and disinfection.

The image of Appraisal Kit is used to conduct the preliminary test as onsite test.  The attached image is self-explanatory.