by Andreas Schabauer, MSc PhD
June 2021

Like most process engineers, the WTG team is only satisfied when all streams out of their plants have a purpose and nothing valuable is wasted, all under the provision of a reasonable energy consumption.

So far WTG has built several plants for recycling of wiping solution from intaglio printing facilities and driven up the recycling rate to a minimum of 95% and under even more optimum conditions a rate of 98% can be reached. This means that only 2-5% of the water and the chemicals need to be replaced during each cycle. Each litre of water is used 20 to 50 times for wiping the cylinders before it is discharged with the concentrated ink.

In the recent years WTG went one step further and installed Spray Drying Systems (SDS) in new plants in Malta and India where the concentrate is dried to a dry matter content of up to 98% and the water is evaporated after the removal of dust and organic solvents; returning to the natural atmospheric water cycle as vapour or mist.

This way only 0.02% of the original water content of the spent wiping solution is disposed with ink waste.
Our concern is now to make this ink waste no longer a waste but a valuable resource instead. It contains high quality pigments, fillers, resins etc. and together with printers and ink manufacturers WTG is looking to find ways to make these components able to produce new inks or for coloration of solid materials like concrete bricks or plastic.
Doing this, we are working to close the cycle not only for water but also the other materials treated in our plants and to reach a real cradle-to-cradle process.