In 2009, Arla Foods in Videbaek, Denmark, realized that its current methods of sludge dewatering were unsustainable. The company decided to invest in a new dewatering solution to handle the large volume of wastewater coming from the company’s milk and cheese production. It partnered with Kruger AS, began onsite trials using diverse equipment to compare technologies with the ultimate goal of increasing the level of performance and decreasing operating costs. The company sought a solution that would reduce sludge waste volume and disposal costs, ensure the highest capture rates and enable fully automated operations.
In extensive trials, a suitable technology was identified and utilized to develop a custom solution that yields a more effective, advanced process. Thanks to its expertise across a broad spectrum of products and technology, Andritz Separation delivered a solution that reduces waste, increases capture rates and facilitates fully automated operation.
Solution
Using an onsite centrifuge trailer, Andritz was able to demonstrate successfully how one D5L centrifuge could achieve strong performance, as well as high flexibility and reliability. The centrifuge has simplified the dewatering system by removing the drum thickener, but it was also key to increasing its reliability, reducing polymer consumption and limiting maintenance costs. Other capabilities shown during trials included an increase in cake dryness, a better capture rate (less than 3 to 500 mg/L suspended solids in centrate) and a significant decrease in industrial water consumption (a low volume ofwashing water). Having boosted performance, the next step was to reduce costs by finding the right polymer that would be effective in minimal amounts and to apply the proper automation technologies to enable continuous operation with no assistance from facility personnel.
Results
The machine has allowed Arla to run a fully automated dewatering operation with lower annual waste disposal and maintenance costs at much higher capacities. Thanks to new additives and a more efficient one-step dewatering process, polymer consumption is now significantly reduced. The end result is a comprehensive, customized solution so successful that Arla has since ordered a second Andritz Separation centrifuge for the same site. The final installation of the second D5 decanter centrifuge in 2014 confirmed this choice of technology. The centrifuge design itself – which removes the need for additional washing water and personnel while achieving an exceptionally high capture rate from sludge with a very high organic content – has also proved essential to making cost savings possible.
