Ferrite treatment of wastewater is a promising approach, making it possible to resolve environmental and economic problems, due to the high degree of water purification and final formation of chemically stable sludge with crystal oxide structure and ferromagnetic properties. This chapter discusses the specifics of ferrite treatment of wastewater containing heavy metal ions and its advantages with regard to other physical-chemical technologies. The role of Ç-potential of microparticles Fe3O4 in the formation of spinel structures is discussed. The mechanism of ferritization reactions is connected with the catalytic nature of the running processes and the probability of the intermediate active radical's formation. To make the ferrite treatment more flexible and effective, it can be combined with photocatalytical treatment, which allows acceleration of the oxidation processes during the ferrite sludge formation, and at the same time promotes the destruction of organic contaminants due to the formation of free radicals in treated water.