A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering of the Asian Institute of Technology, Bangkok, Thailand.

Thesis (M.Eng.) - Asian Institute of Technology, 1976

Economic of algal protein production, harvesting and processing from high-rate oxidation ponds was carried out in this research. The objective was to determine the most economical process for algal production. AIT sewage was used to feed the pond operated both at non-chemical aid (Phase I) and at chemical aid of 2 mg/l of Purifloc-C31 (Phase II) or at 0.4 me/l of Ferric chloride (Phase III) o Processes being used for initial concentration of algae in algae- laden water samples taken from the pond were centrifugation, flotation and autoflocculation. Drying techniques used for algae drying open-air sun drying and sand bed drying. Palletization of algae both as sole constituent and in combination with tapioca was studied for improving marketability of algae. An economic analysis was also studied for evaluating the most economic cost of algae. It was found that autoflocculation with 7 hours detention time was the most economic process . An autoflocculation plant having capacity of 15, 750 m3/day, with 200 mg/l of algal yields , will give a yearly profit of about US$111, 200, if algae are sold in the same price as conventional fish meal.