Working toward a major sustainability goal, Sappi North America has successfully reduced the amount of specific landfilled solid waste from our Somerset Mill and improved the mill’s boiler stability and emissions control.
Wastewater treatment sludge at the Somerset Mill contributes to the amount of specific landfilled solid waste created by mill operations. This sludge is typically burned as fuel, but at times of nonoptimal running, it must be placed in landfill. SNA chartered a Lean Six Sigma project team to minimise sludge that moves to landfill and to maximise the fuel value of that sludge.
By reviewing how the sludge moves through the mill systems, the team identified periods in which the feed of sludge was disrupted or fully stopped.
Using Lean Six Sigma DMAIC (define, measure, analyse, improve and control) techniques, the team isolated factors contributing to the stoppage and improved the uptime of the sludge feed from a baseline of 90% to over 98%.
These changes have also allowed the mill to achieve significant improvements in boiler stability and emissions control.
In addition, the team partnered with suppliers and developed training for operators to improve the solids content of the sludge, which then improved its burn efficiency. Together, these efforts have increased sludge burn rate and lowered sludge volumes going to landfill by over 30%.