CHAPTER 1INTRODUCTION1.1 Background of the Study1.1.1 Coagulation ProcessCoagulation is one of the processes involved in wastewater treatment. This is the main water treatment process related to these studies. The main purposes of the coagulation process are to separate suspended solids from water and remove turbidity from water. Coagulation is almost similar to the other process of separating suspended solids called flocculation. The operating principle of the coagulation process is to destabilize the colloids suspended in wastewater by neutralizing the forces that keep them repelled towards each other. The coagulant is an agent responsible for neutralizing the electrical charges around the colloidal particle. Commonly the charges surrounding the particles have a negative charge, called the zeta potential. By neutralizing this charge the particles will stick together. To improve the agglomeration process, flocculants are added to the wastewater. Flocculants involve a stirring process which will subsequently allow them to bridge and become larger. As the colloid becomes larger and heavier, it will settle to the bottom of the tank under the influence of gravity. Finally the suspended solid separated from the water by filtration process.1.1.2 CoagulantThe coagulant is an agent that ensures the success of the coagulation process. One of the factors in determining the effectiveness of coagulation is the types of coagulants used. Different types of coagulants not only have different effects on the physical appearance of the water but can also give a side effect to users of the treated water. The cost of coagulant also varies depending on the type of coagulant. So the selection of coagulant is one of the steps that must be taken into careful consideration to avoid any... middle of paper...2.1.3 ANIMAL-BASED COAGULANT2.1.4 Coagulant from ChitinChitin is a type of biodegradable polymer found abundantly in nature. It is commonly found in crustacean shells, in the cuticle of insects and also in the cell wall of plants (Ospima et al, 2014). Chitin has a wide range of applications such as medicine, agriculture, food industry and wastewater treatment industry due to its unique chemical, physicochemical and biological properties. Chitin is a linear polymer consisting mainly of β-(1-4) linked 2-acetamido-2-2 deoxy-β-D-glucopyranose units and partially of 2-amino-2-deoxy-β-D-gucopyranose units to β-(1-4). Completely or partially deacetylated chitin is called chitosan. The molecular mass of these two polymers can reach up to millions of g/mol demonstrates that these two polymers can be excellent coagulants.2.1.4.1 Source of chitin