Case Study: How ’Moisture Gates’ improve paper quality, transparency and yield

Our Rouen and Dueñas Paper Mills have successfully implemented a new Microwave Measurement System, enabling us to efficiently and accurately measure moisture content in Paper for Recycling (PfR) arriving at our mills.

DS Smith is Europe’s largest cardboard and paper recycler, so we understand the opportunity for packaging to play a powerful role in a changing world. This is why our purpose is Redefining Packaging for a Changing World. We think differently, innovate and put sustainability at heart, developing strategies to increase recycling, reduce waste and understand our customer and supplier needs.

Following positive results in France and Spain, we are beginning the pan-European rollout of the new quality control system. It will allow us to accurately measure moisture content in PfR, improve the quality of raw materials and increase transparency with DS Smith suppliers to ensure fair market price.

The challenge: measuring moisture content in PfR

Accurately measuring the moisture content in a truckload of paper has always been challenging. Existing methods, such as moisture meter plates, ovens and other manually operated systems only measure a ‘spot’ or a small percentage of the overall volume. The same load, measured by these methods, often produces conflicting moisture readings. In addition, paper yield can vary by as much as 6% between summer and winter as a result of moisture content variation alone. ­

Another factor is overcoming the frustrations felt by some suppliers that are caused by unreliable data and old technology. When high moisture content is detected in bales, suppliers understandably seek reliable, transparent data, to support the credit that DS Smith offers. 

DS Smith has met challenges like this before. In our Customer Surveys, suppliers have requested more data-driven insight and auditable solutions to help them improve their quality and increase their financial returns. In response in 2019, DS Smith introduced Near Infrared Technology (NIR) to more accurately measure fibre quality and identify contaminants such as metal and plastic. Now, an equally accurate and transparent solution is required to measure moisture content. 

Moisture Gates: The measurement solution to moisture measurement in the paper industry

All trucks arriving at our mills pass through a scanner called a ‘Moisture Gate’ which allows us to accurately identify the average moisture content of the load, not just the surface area of the delivery. Around 75% of the truckload is scanned within 30 seconds and, in less than one minute, a reading for the entire truck is calculated, recorded, and the truck is free to proceed. As the process is so efficient, vehicles aren’t delayed at the mill.

1. Truck (with horizontal bars removed) passes through Moisture Gate at 3-5 km/h. Moisture Gate radiates the area between the antennas and scans load.

2. Each scan covers around 5m³ of the load. It takes about eight scans to measure a truck – all completed in just 30 seconds.

3. In less than one minute, an accurate moisture content readout is delivered on the screen without any manual intervention – data is subsequently sent directly to the supplier in an easy to read format and weekly reports compiled.

What are the benefits?

At DS Smith, quality is at the heart of our operations and we are continually seeking ways to keep PfR in the supply cycle as long as possible. Through driving innovation, we have found a way to increase the quality of raw materials entering our mills and cut waste using no more material than necessary by improving our yield.

Our suppliers now have transparency, access to accurate data, and are paid a fair market price for their EN643 specified material. As Moisture Gates involve no moving parts, our suppliers’ drivers need no additional training.

To further strengthen our supplier relationships, our new system enables us to share moisture content data in an easy-to-read format and via weekly reports. This data can help suppliers to identify and address any issues and help them advise customers whose waste management processes may need to be adjusted to meet targets.

By improving measures of incoming Paper for Recycling our mills could see increased manufacturing yields. Not only this, but our transparent reporting system will provide clear communications to customers.

— Nuno Messias, Paper for Recycling Purchasing Director at DS Smith Recycling Division in Iberia

At DS Smith, everything we do is focused on providing customers with innovative, effective, and sustainable strategies. Our commitment to quality and use of innovative technology means we can help our customers increase their recycling and reduce their waste, and together, we can work towards a circular economy.