Ferrate(VI) in the Treatment of Wastewaters: A New Generation Green Chemical

Fresh water resources are under tremendous stress throughout the globe. Many areas all along the developing or even developed nations indicated, the fresh waters are greatly contaminated by the discharge of untreated sewage/industrial effluents and even variety of toxins entering naturally. Environmental regulations and public health concerns stated that wastewaters collected from municipalities and communities supposed to be treated as to meet the standards given prior its discharge/disposal into the aquatic environment. An advanced primary treatments aiming to enhanced the removal of colloidal particles and organic constituents from wastewaters, known to be an essential primary step and a starting point leading to fewer remaining particles and organic/inorganic contaminants, which in turn favorable for subsequent biological or physico-chemical treatment process. It is observed that the coagulation and oxidation/disinfection are two important unit processes for water treatments. Coagulation destabilizes colloidal impurities and transferred small particles into large aggregates and facilitates the several dissolved contaminants to adsorb onto the surface of these aggregates, which can then be removed by sedimentation and filtration. Disinfection is design to introduce the chemical dose enabled to kill the harmful organisms’ viz., bacteria, pathogens and viruses etc. from the wastewaters. Additionally, the usual method of sewage/municipal or even several industrial waste effluents treatment processes contained with large amount of sludge having various organic and inorganic compounds occurred, pose serious safely and quality aspects related to environmental concerns. Further, the final dewatered sludge (often called biosolids), which is to be land applied, endocrine disruptors and odors of the solids as well as pathogens have been brought under the serious attention towards its impact of the biosphere. However, such biosolids once treated carefully, may serve as an economic values as a soil conditioners and fertilizers etc. Further, the usual sludge handling processes viz., thickening, drying, digestion and lime stabilization contribute to the on-site odors, became a severe environmental burden. Different types of organic sulfides and amines are produced in wastewater treatment facilities to give unpleasant odors. These processes are not effective in destroying toxic components of sludge viz., endocrine disruptors and potential pathogens.