Catalytic Oxidation of Sulphide Laden Tannery Wastewater without Sludge Production | Original Article
The beam house operations in tanning process of hides / skins comprises of soaking, liming, fleshing and deliming operations. The removal of animal hair and flesh from skin is facilitated by the liming operation. About 5m3/ton wastewater containing a credible concentration of sulphide and dissolved proteins are discharged.lt is highly alkaline and having high BOD/COD ratio. The biological treatment of wastewater that occurs at neutral pH requires neutralization of the wastewater using acidic stream. This results in the emission of hydrogen sulphide which is considered to be highly toxic gas. The present investigation employed Heterogeneous Peroxide oxidation process(HP0) for the oxidation of sulphide in the lime sulphide liquor without sludge production with simultaneous removal of COD from wastewater. The screened effluent was adjusted to pH 9.7 using conc. Sulphuric acid and it is catalytically oxidized with Hydrogen peroxide 3.921mM/L and Nano Porous Activated Carbon (NPAC),30 g/1, at HRT 24 hr. The dosage of Hydrogen peroxide, mass of NPAC and HRT were optimized The integrated catalytic and biological oxidation in FICCO (Fluidized Immobilized Carbon Catalytic Oxidation) reactor eliminated COD, sulfide, Total Kjeldahl Nitrogen, protein, Amino acids and Total organic compound by 66.66%, 98.95%,75.67%,44.21%, 48.98% and 62.18% respectively. The sulphide present in the wastewater was catalytically oxidized to sulphate and ammonia content was increased by 78.05% by cleaving protein molecules.