Paper Title
Comparison of Coagulation and Pre-Chlorination/ Coagulation for Chlorella SP. Removal

Abstract
The treatment of green algae in the water is a primary problem in the water treatment plan and could not be treated by conventional process due to the limitation of treatment efficiency.Moreover, differences of water quality, pH, algae species can influence the conventional technique such as pre-chlorination and coagulation treatment. There are many arguments, still wondering which technique to provide both low cost and high efficiency in terms of removing the green algae. Therefore, the comparison of coagulation and pre-chlorination/ coagulation for green algae removal were investigated. The green algae used in this study was Chlorella sp. and the monitoring parameters were pH, turbidity, algae concentration and chlorophyll-a which were analysis after testing with a jar-test method. The results showed that pre-chlorination/coagulation had higher algae removal efficiency than coagulation. For pre-chlorination/coagulation, the pH and turbidity were 7-8 and 0.5-1.0 NTU, respectively and quite stable. Applying 20 mg/L of FeCl3 with8 mg/L of NaOCl (F:20+N:8) indicated that algae concentration and chlorophyll-a was removed higher than coagulation about 3.0% and 5.0%, respectively. In addition, decreasing rates of algae regrowth 10.0% was observed within 3 days. Keywords - Coagulation Process, Pre-Chlorination/ Coagulation Process, Chlorella sp., Regrowth