This review summarizes data available so far on the progress made in t
he study of Fenton and photo-renton reaction in chemistry, biology, an
d environment. In the first part, the chemistry of Fenton reaction is
described. In the second part, the biology of Fenton and metal-ion cat
alyzed Haber-Weiss reaction is discussed. In the third chapter, partic
ipation of Fenton and photo-Fenton reaction in natural water chemistry
and cloud chemistry is presented. Finally, the practical utilizations
of Fenton and photo-Fenton reaction in wasterwater treatment processe
s are discussed.