Optimization of temperature and coagulators concentration to reduce biological oxygen demands in whey using fraction of full factorial statistical method

Whey is one of the major dairy wastes which is rich in organic compounds. These compounds reduce oxygen dissolved in water, inactivating the active water ecosystem and cause the loss of aquatics. An optimized composite formula of coagulator concentrations including Pectin, Sodium alginate, Aluminum sulfate and Iron chloride and coagulation temperature was determined to reduce biological oxygen demands in whey. Experiments designing was done using fraction of full factorial statistical method and Qualitek-4 software and Taguchi approach was applied for results analysis. Optimal conditions was obtained in Aluminum sulfate, Sodium alginate, Iron chloride and Pectin concentrations equal to 2, 0.02, 1.5 and 1 g L-1, respectively and temperature as 25 degree centigrade. The expected reduced percentage in biological oxygen demands in optimal conditions was estimated as 33.722. Coagulating temperature was recognized as the most effective factor to reduce organic load of whey with a contribution share equal to 63%. Aluminum sulfate concentration changes showed less effectiveness (1.7%) and Iron chloride concentration changes had a negligible impact as 7%. The changes of Sodium alginate and Pectin concentrations were effective as 18 and 10%, respectively in reducing the biological oxygen that is needed.