| abstract |
Disclosed is a wastewater treatment method for reducing and purifying the chromium ion concentration, COD value, etc. of wastewater generated in a leather tanning process of a leather treatment plant so that it can be reused as water. SOLUTION: For both chromium ion-containing wastewater and chromium ion-free wastewater, pH adjustment by adding inorganic salts, wastewater treatment agent containing activated carbon, and polymer flocculant are appropriately added to improve the efficiency of chromium ions. In addition to the insolubilization removal (removal rate of 99% or more), it is possible to efficiently remove oxidizable substances such as organic substances in the waste water, and to reduce the COD reduction rate to 80% or more. [Selection figure] None |