Tanneries Liquid Waste Management

Abstract

Tanneries use much of chemicals such as sodium sulphide, calcium hydroxide, ammonium sulphate, acids, basic chromium sulphate bactericide and fungicide. All these substances contribute to the environment pollution, and although biological and chemical treatment methods are used, yet these methods are not effective enough to reduce pollution to the international standard level required. This pollution problem has to be solved completely via recycling through all wet processes from soaking to retannage.In this study the spent solutions were recycled form soaking, through retannage processes many times with addition of makeup of chemicals and water ,that are normally used , The produced crusts quality were tested and the results were found to be satisfactory.Thickness(mm)=0.8,Tensile strength (kg/cm2) =149,Elongation at break)%(=34,Tear strength (kg/cm)=43,Load at grain crack (Kg)=20. Destination at grain crack (mm)=6. A comparison of cost estimate of two types of tanneries one of them used conventional technology of waste treatment and the other use recycling from soaking through retannage was investigated. The method of recycling was found to be superior due to saving in water and chemicals as well as protection of environment .In addition to these advantages it is not required to establish a new effluent treatment plant which reduce the total cost of processing.It is recommended that the recycling method should be generalized in all tanneries in Sudan.