Waste Treatment Equipment

1. The Leather Waste

Summary:

The waste discharged from the leather manufacturing process has a variety of forms. Not only does it have a great deal of variation in water quality but also it requires a lot of water for treatment. If water is used at 40-80 L/kg of the original leather(cowhide), almost the entire amount is discharged as waste. Major chemicals used are lime (Ca(OH)2), sodium sulfide(Na2S), ammonium chloride(NH4CL), sodium hydrogen sulfide (NaHS), salt, surface active agents, and chromium compounds. It is a typical malignant industrial waste and the treatment is not easy. Thus, these treatment facilities are suggested to treat this waste effectively as an effort to conserve our environment.

2. The Industrial Method of Waste Treatment

A. Pressure Flotation Method

B. Coagulation Sedimentation Method

C. Reduction Stabilization Method

D. Pressure Flotation Method - This is the method to remove through pH adjustment and flocculation feeding, suspended fine-particle materials and colloidal floating materials from the physically-pretreated waste in the pressure flotation bath and then to treat the waste biologically.

3. The Applied Areas:

This method ls applied to the cases in which the specific gravity of suspended floating materials is about 1 and the waste contains a lot of organics among the dissolved impurities.

4. The Applied Conditions and Characteristics

The bubbles formed by air discharged from the ejectors and the compressors adsorb fine particles while rising and floating the particles. Then the floated particles are removed with a skimmer. This method has the following advantages over the coagulation sedimentation method.

- The amount of treatment per unit hour is greater since the flotation speed is greater than the sedimentation one.

- The bath capacity is smaller than that of the sedimentation bath.

- The water content of floated scum is low.