Paper Mill Studies of Flocculation Processes - Rapid Mixing in Water Treatment, 1995 Environmental Conference Proceedings

Matthias Geidel

Voith Sulzer

Wolfgang Baßler

Voith Sulzer

In chemical water and wastewater treatment the flocculation process is widely used to remove suspended solids or colloidal particles from liquid. Since enormous amounts of water have to be treated in paper mills, flocculant consumption is an important cost factor. Beside the type of flocculant used for the clarification process, the consumption and efficiency of water treatment is influenced by the method of blending and design of the piping along the blending section. For efficient blending a rapid and homoge-neous distribution of chemicals and treated liquid is required. Experiments in a paper mill were conducted with a newly devel-oped pipe reactor equipped with a static mixer and an in-line jet injector. Blending performance and flocculant consumption were investigated. Compared with operation without a mixing device, flocculant consumption is reduced by 35% with the static mixer and 45% with the jet injector. Furthermore, the experi-ments prove a connection between flocculant consumption and the quantity of »anionic trash« introduced into the water system by reductive bleaching agent. The results presented point to a substantial reduction in the cost of chemicals.