Читать книгу Industrial Environmental Management - Tapas K. Das - Страница 33

The easiest connections for industrial clusters are through a simple, direct waste exchange. The next easiest route is to develop an intermediary process that will take one industry's current waste stream, convert it to a usable form, and transfer it to a purchasing industry. Now we consider briefly the pivotal function of conversion technologies as illustrated by the problems encountered in the paper recycling industry as it works toward attaining Zero Emissions in the United States (see also Chapters 7 and 9).

Paper recycling is quintessentially “green.” But current processes used to de‐ink paper remove only 70–80% of the ink particles, leaving recycled papers an unattractive gray. The wastes are a toxic mix of ink, short fibers, coating chemicals, and paper fillers that requires both primary and secondary treatment before disposal. De‐inking is both inefficient and expensive, and results in a product that is often higher priced and lower quality.

Under the auspices of ZD industries, a conversion technology is being developed that results in 100% removal of ink and 3 viable outputs. The recaptured ink could be reused in printing or for making pencils (as is already done with ink from photocopiers). The long fibers could be made into paper again or used in cardboard. The remaining sludgy mixture of short fibers and residues could be dried and used as acoustic insulation inside building walls or as ceiling tiles. The sludge could be used to make shock‐absorbent packaging such as egg cartons or replacements for corrugated cardboard.

The industrial cluster built around paper recycling thus includes recapturing ink, making new paper, and making building and packaging materials. Canada, Latvia, and Italy have tested this conversion technology, the steam explosion system. Many cities, states, and national governments, however, require that recycled paper be used in newspapers, and where these regulations are in force, a system that produces a grade of paper better than that needed by newspapers is not likely to be implemented.