Treatment of dairy effluent by ozonation: Design of experiments by response surface methodology

Dairy industries are one of the major sectors consuming huge amounts of water converting into effluents during various processes. Dairy effluents contain complex organic matters which are not easily degraded by simple methods. Hence, dexterous and effective techniques are required to treat these types of wastewater. In this regard, advanced oxidation processes like ozonation are an emergent approach to ameliorate the wastewater treatments. Ozone (O3) is a powerful oxidizer, and the strong electrophilic nature of O3 enables it to react with various organic compounds. In the ozonation process (OP), the reaction between O3 and pollutants can be explained by direct or indirect reactions, i.e. through the reaction with O3 or decomposition of O3 molecules and formation of hydroxyl radicals (°OH).The Box-Behnken method based on RSM was employed in the planning stage of the experimental approach, and the results indicated that under optimal conditions, the maximum CODr efficiency of 55.95% was obtained that was verified experimentally.