school energy&environment

Production of waste paper

The production of waste paper is very similar to the production of virgin fibers, although a different mixture preparation is required. Infact, during this phase all alien materials which could contaminate production, as iron, plastic glues, glass, paraffins, etc., need to be removed from the pulping process. The presence of these materials, infact, influences the quality of paper and creates problems during the production process. Paper is later reduced in pulp and filtered through a series of strainers which initially remove the coarser parts and progressively eliminate the smallest ones. Producing recycled printing paper requires in-depth straining. Starting from cheap raw materials to obtain paper with a sufficient degree of white, deinking is employed to remove ink present in the pulping process. The whitening process or reinking clearly requires products which aren’t harmful for the environment.
Oxygen is employed rather than chlorine and attention is required to avoid the dispersion of harmful products outside the paper mill. Recycled paper production avoids the use of optical brighteners which modify the wavelength of ultraviolet radiations making it visible an thus artifically increasing reflected light favouring deinking. Both impurities removed and inks must be stocked and employed for other uses. Paper produced from pulping can be similar to paper produced from virgin fibers depending on how sophisticated are the straining and deinking processes. At the end of the straining process the paste produced is passed through a flat board machine and manufactured like any other paper. Paper mills must be equipped with special machinery for the treatment of waste paper, processing scraps and wastewater. Residual sludge is used as agricultural amendment, within road foundations and brick production. Paper made from organic waste which is difficult to dispose, as algae which develop excessively, gives a great contribution to the environment.