Water Reuse in a Paper Reprocessing Plant.

摘要

This project was undertaken to determine the feasibility of water reuse in a paper reprocessing plant with the goal being to 'close the loop'or to demonstrate zero discharge technology. Before the project began,Big Chief Roofing Company at Ardmore,OK,was discharging 7.89 1/sec (125gpm). Normal operation is now zero discharge with approximately 0.76 1/sec (12gpm) fresh water make-up replacing evaporative losses. However,weekly clean-ups still result in an effluent of approximately 15.14cu m (4000gal) a week. Additional clear water storage capacity could eliminate this weekly discharge. Project scope included identifying and solving problems resulting from increased recycle of process water,and determining costs,benefits,and effect on product quality. The favorable cost/benefit ratio experienced at the plant demonstrated an economic advantage of in-plant control over end-of-pipe treatment. Attaining zero discharge operation has the further benefit of eliminating the problems,cost,and liabilities associated with operation under a discharge permit. Economic benefits observed during zero discharge operation included reduced water supply costs,reduced wastewater treatment costs,improved yield,improved drainage and greater dryer section production. The benefits were partially offset by shorter felt lives,increased corrosion control cost,and process modification cost. No degradation of product quality was observed.