Impact of temperature on ferric chloride performance in water coagulation

Temperature has an essential function and becomes an important parameter in a coagulation process as it influences metal ion hydrolysis reaction rate. In order to get further explanation, a research using ferric chloride as a coagulant has been performed. The research aims to find out more about the effect of temperature on coagulation performance using turbidity, floc size, ferric, and water content parameter. The temperature 5℃ - 45℃ with an interval of 5ºC has been investigated to simulate field (i.e. outside) measurements in winter, spring and autumn, and summer, respectively. The result shows coagulation performance isaffected by temperature elevation. Turbidity gets lower for temperature between 5℃-40℃ and gets higher for temperature 45℃. Floc size becomes larger for temperature 5℃-40℃ and becomes smaller as temperature increase.At temperature between 5ºC and 15ºC, the higher the temperature, the lower the ferric residue produced in coagulation water. For floc water contents, there is no virtually link between temperature and floc water contents. Temperature correlated well with turbidity value (-0.876) and floc size (0.985) but not correlated with ferric residue (0.366)and floc water content (0.179).