Commercially Viable Products That Utilize Pulp and Paper Mill Sludge as a Raw Material Source, 1999 Environmental Conference Proceedings

Paul Dongieux

GranTek Inc.

In 1989, Mr. Edward Lowe, the “father of the cat box filler industry’ created the company now known as GranTek Inc. for the purpose of producing value added products from “paper mill sludge”. Since that time they have been producing and offering for sale, various granular products produced horn paper mill sludge. Sludge that previously would have been disposed of via landfill , landspreading, landcover or similar uses. Thermo Fibergen, a Thermo Fibertek company acquired GranTek in July of 1996.

The challenges associated with producing a high quality end product from waste paper sludge are too numerous to list. Personnel from both GranTek Inc. and Fort James Corporation (sole supplier of sludge to the Green Bay facility) must address these challenges. Parameters such as ash, moisture, pH and others must be monitored and recorded. Also procedures must be in place to address potential upsets and downtime at both facilities. Operators of the process must be continuously aware of such parameters in order to ensure that the final product quality specifications are met.

The company’s manufacturing facility located in Green bay, WI is IS0 9002 certified. They hold both process and use patents associated with the value-added products manufactured at the Green Bay facility. The process is comprised of a receiving area where sludge is delivered by Fort James at approximately 40% solids. This sludge is dried, reduced in size by high speed size reduction equipment, agglomerated into unique granules, dried, screened and sent to bulk storage prior to shipment to the end customer.

The company utilizes the processed sludge as received to produce a variety of virtually dust free, highly absorbent granular products: Biodac, an inert carrier utilized by the agricultural chemical industry as a substrate for granular crop protection products; Gran-sorb, an incinerable general purpose oil and grease absorbent; and finally, through the use of various processing steps and additives it is possible to produce both a clumping and conventional cat box filler, PaPurr. GranTek Inc. holds both process and use patents for all of the above uses.