Water Reuse and Effluent Treatment in the De-inking Process

Effluent resulting from the de-inking process is difficult to treat because it has a high pH value and contains many anionic constituents such as ink particles, fine suspended solids and surfactants used in the de-inking process. However, as much water is used in this process, it is becoming increasingly more important to recover the effluent and reuse it from viewpoints of both water conservation and quality improvement of de-inked pulp. This article describes the coagulation method, using a polycation instead of alum as a new recovering technology with waste water, can get rid of fine particles and suspended solids which cannot be removed by flotation methods, giving clear recycling water. As a result it has such advantages as high brightness, good strength, and so on.