Efficient Water Usage In Recycled Fiber Production
One small change made by Production Superintendent Phil Nysse at Sustana’s Fox River Fiber mill in De Pere, Wisconsin managed to reduce fresh water consumption at the plant by just under eight per cent per ton of fiber recycled, since 2016 when the change was made.
Image source: Sustana
In the below interview, Phil answers questions about the simple fix that made a big impact:
Where is the water at Sustana’s Fox River Fiber mill sourced from?
PN: Even though we are located near the Fox River, all water used in production is sourced from an onsite well. This well water, accessed from underground, remains cold and consistent in temperature.
Use of consistently cold water from underground distinguishes Fox River Fiber from facilities which use open water from a river; the temperature of open river water may fluctuate and change depending on the seasons.
What is the role of water at Sustana Fox River Fiber facility? How is it used in production?
PN: Water is used throughout the entire manufacturing process, to carry fibers through the production system. Typically, water is kept cold in the front half of production and hot near the end of the process.
Water is kept cool in the beginning to ensure malleable contaminants (ex: solid impurities and ink particles) can retain their structure and be filtered out, while hot water at the end of the process will allow, among other things, to help production machines operate more effectively.
Fresh well water itself is required for certain purposes: roughly half of all fresh water is used for seal water systems on production equipment. The remaining half is used exclusively for thermal purposes to cool down production systems in the mill.
Describe the changes made to the water system at the Fox River Mill
PN: While doing a sign off on our production process, I noticed some pipes near the end of the production line were sweating – cold from fresh water and wet with humidity. This was occurring at our wet lap machine, an area where water needs to be as hot as possible, for optimal equipment performance.
I went back to the area with a production operator and flagged the cold-water sources. From there, we were able to work with a pipe fitter from our maintenance team to divert the cold water back to the beginning of the process and to our cold-water supply.
How did the idea for this change come about?
PN: As part of a cost-savings initiative in 2017, we were looking to take on projects that would reduce production costs of recycled fiber.
We stumbled on this water saving opportunity in late 2016 by accident. While working in the back of the wet lap machine with the production operator, in an area that most people don’t look at, we noticed the sweaty pipe which I knew was cold.
While our initial intention was to save natural gas and reduce production costs, we are also consistently seeking ways to reduce water consumption. This change ended up saving water while also saving on gas.
How much water did this change end up saving? How did this change the company?
PN: As soon as the change was made we saw instant results in terms of water savings. In going through the numbers, we accounted for a minimum of 100 gallons per minute of fresh water saved because of the change.
The 100 fewer gallons used per minute means less water to bring in from a well. Furthermore, seeing as every gallon we bring in is treated in our on-site effluent water treatment plant before being discharged back to the city, this also means less energy used in treating and discharging water.
In terms of thermal savings of natural gas, measured in “therms” units, we have quantified a savings of 1,140 therms per day.
Furthermore, increasing the temperature of our wet lap machine has helped the machine to run better, resulting in increased production efficiency.
The instant benefits of this change have paid for themselves – while production output has increased over the years, from 250 tons of fiber per day since I started with Sustana 17 years ago to over 450 tons today, the amount of water used in production has only decreased.
Source: Sustana Group