The authors have analyzed a modern technological line of the latest chemicals for the recovered paper processing and de-inking in terms of reducing the amount of wastes arising during the production. The authors have also investigated the effectiveness of selected chemical aids (coagulants and flocculants) supporting the process of sludge dewatering. 12 different types of flocculants were tested. The best chemical agent was selected as well as its optimal dosage. The highest dynamics of sludge dewatering improvement (expressed by the dewatering time under standard conditions) was observed with the ECR3 agent dosage of 6 - 6.5 kg per tonne of the absolutely dry sludge. Long-term analyses of the tested line have proved that the retention aid and its dosage were selected correctly.