Wastewater in the food industry contains recalcitrant organic compounds and a certain degree of toxicity. Present wastewater treatment plants are insufficient in dealing with the increasing complexity of effluents from modern food industries. Improperly treaded wastewaters can lead to spoil soil and are threads to aquatic life. The reaction of these recalcitrant chemicals with reactive radicals is an efficient treatment strategy. Researchers have proposed advanced oxidation processes (AOPs) that generate reactive radicals including ozonation, UV irradiation, (photo-) Fenton process, etc. This chapter reviews laboratory-scale and pilot-scale AOPs to incorporate with conventional pre-treatment methods and to evaluate their effectiveness and factors including operation condition and catalysts to optimize the process. Further research related to novel catalyst synthesis and cost evaluation of pilot-scale study is suggested.