Compounds of Iron in oxidation state (VI) have the advantage of being strong oxidizing agents and bactericides; which explains their particular interest in the treatment of water. Furthermore, their reduction gives rise to ferric hydroxide. Their flocculating power helps in the removal of organic pollutants and minerals (hydrocarbons, heavy metals, radioactive isotopes, etc. The synthesis of ferrate (VI) is proving to be very difficult because of the instability that gives them it high oxidizing power and that existing synthesis processes will take place at laboratory scale. This work has focused on the synthesis methods of alkali ferrate (VI): stable at room temperature, wet, electrochemical and dry. The storage rate exceeds 12 months, encouraging the bulk synthesis of ferrate (VI). The study of these ferrates bactericidal effect and their use in the treatment of water Mehraz River's Fes in Morocco is very promising. The production of ferrate (VI) alkali metals on industrial scale requires purification and high stability at room temperature to facilitate transportation and storage.