Inorganic Salts Specific Impact
Raw hides and skins are subject to autolysis due to activity of enzymes and attack by microorganisms present in the air, hair, dung, floor, etc. The ratio of both autolysis and bacterial degradation increases with temperature.
Preservation protects the raw material by:
i) inhibiting enzymes’ activity
ii) arresting the growth of microorganisms.
Advantages | Disadvantages |
Widely available at modest cost | More expensive than fresh or icing |
Simple, easy to apply | Heavy pollution of wastewater (salinity), that cannot be removed by normal treatment because of extremely high energy costs |
Very reliable if carried out properly | Disposal of polluted/excess salt a problem |
Very limited capital investment | Investment cost high if mechanised |
Allow ling storage & transportation, stock holding, more uniform lots | Reverse Osmosis (RO) normally not affordable. |
The residual sulphides in effluents is easily oxidized into sulphate. The real issue is the risk of the formation of highly toxic hydrogen sulphide due to:
Poor segregation of streams and mixing of alkaline with acidic exhausted floats as the pH of the effluent drops below 9.5;
Anaerobic conditions and reverse reaction (action of sulphur-reducing bacteria).