USE OF POLYELECTROLYTES IN MECHANICAL SOLID-LIQUID SEPARATION

Use of Polyelectrolytes in Mechanical Solids/Liquid Separation. This a rticle shows how optimisation tasks for the dewatering of sludge can b e solved by starting from studies of chemical structure and steric pro perties of polyelectrolytes and laboratory experiments based thereon w ith a transportable computer-aided flocculation and dewatering apparat us. The optimum polyelectrolyte dosage lies in the range of the critic al concentration c (viscosimetirc measurements) of the dissolved poly electrolytes. On optimisation of the flocculant regime for mechanical solids/liquid separation by combined addition of anionic and cationic polyelectrolytes (dual process), it is necessary to consider the overa ll system of sedimentation and filtration. In an industrial scale plan t, the consumption of flocculant could be reduced by up to 10% compare d to laboratory studies. At the same time, the dewatering behaviour co uld be improved by up to 60%, a shearing strength of the sludge in exc ess of 20 kN/m2 reliably established, and plant operating reliability achieved for changing sedimentation properties.