Title
Various valorisation routes of paper intended for recycling – a review
Authors
MARINA VUKOJE and MIRELA ROŽIĆ

Received Dedicated to Acad. Bogdan C. Simionescu on the occasion of his 70^th anniversary
Published Volume 52 Issue 7-8 July-August
Keywords paper for recycling, printing inks, material and organic recycling, recycled fibres, bioethanol, cellulose derivatives, energy recovery, life cycle assessment

Abstract
This review outlines the possibility of utilizing paper intended for recycling in different processes. Paper is mainly recycled for producing recycled paper, but in the last decade it has been also used for obtaining cellulose derivatives and bioethanol. The production of recycled fibres from paper by the conventional chemical flotation deinking process is the most widely used method worldwide and therefore, the most often described. In addition to flotation, the methods involving enzymes, ultrasound and adsorbents are also promising, but their application in paper recycling facilities is still limited. The efficiency of these processes mostly depends upon the interaction between papers and printing inks. The presence of printing ink residues in recycled pulp can cause health and safety problems because of their toxic components. Moreover, the effluents from paper recycling plants are influenced as well by the raw materials used for recycling, which may lead to high organic loads. The paper collected for recycling is sometimes contaminated with food or is wet, and in such cases, it is recommended to use the paper for bioethanol production and organic recycling. Energy recovery via pyrolysis, gasification and combustion is also recommended, but only in the case the produced heat is used for other applications. In order to choose the most effective waste management method, life cycle assessment (LCA) can be used. However, the existing published literature generally overlooks the aspects related to the presence of printing inks in the paper intended for recycling. This literature review highlights the fact that the influence of the most common non fibrous materials in paper, which are printing inks, on the process efficiency of the recycling methods is poorly described.