Biological treatment of printing ink wastewater

Abstract

Printing ink wastewater is usually very difficult to treat biologically and its chemical oxygen demand (COD) far exceeds standards of discharge. The COD in wastewater is usually 3,000 to 8,000 mg/L after flocculation and sedimentation. Herein, a strain of bacterium was isolated from the sludge and identified as Bacillus sp. and utilized to treat printing ink wastewater. The application of bacteria to degrade printing ink in wastewater is discussed in this paper. The influence of N and P sources on COD removal, and COD removal in combination with glucose was also discussed. More than 85 per cent of the COD could be removed using the proposed biological process. A novel internal airlift loop bioreactor with bacteria immobilized onto ceramic honeycomb support was used for the wastewater treatment.