CIRCULATION ENGINEERING FOR ACHIEVING NEAR-ZERO DISCHARGE OF TANNING WASTE WATER

摘要

Provided is circulation engineering for achieving near-zero discharge of tanning waste water, characterized by stepwise and independently recycling waste water from the processes of pre-soaking, main-soaking, liming, reliming, deliming and softening, pickling and chrome tanning, retanning, neutralizing and dyeing. The recycling of all the waste water from the above-mentioned processes is realized. This technique has been practised and verified in practical mass production in a tanning workshop of Biosk (Shangqiu) Chemical Co., Ltd. The present invention achieves the recycling of waste water from pre-soaking to dyeing, greatly reduces polluted water discharge, completely solves the difficult problem of tanning pollution, and at the same time can ensure the quality of finished leather, effectively reduce the loose grain rate of the finished leather, improve the compactness and fullness of the finished leather, and can achieve the saving of 15-55% of chemical materials, for instance, saving 35-65% of chromium powder, in which some chemical materials can be saved by not less than 90%, and individual chemical materials, such as table salt, can be saved by 100%.