Features Equipment & Systems
Tasster sludge press benefits confirmed

Tembec’s newly-acquired Matane (Quebec) BCTMP mill is now operating at full capacity producing between 550 and 625 tonnes per day of a variety of pulp grades using between 100% fir or aspen wood chips in varying species proportions to meet clients’ specifications. Peroxide bleaching is done whenever higher brightness objectives have to be met.

The mill was built and commissioned in the early 1990s at which time a complete effluent treatment station with primary and secondary treatment was also put into service. For sludge dewatering purposes, two Tasster screw presses, model PFAE 1000 were acquired and have since been in operation to handle the entire mixed sludge volume produced in the plant. As is often the case with new mill start-ups, there were some difficulties in achieving steady operation for a while. Therefore, it was not uncommon to have wide fluctuations in P/S ratios which, were reflected in erratic sludge dewatering equipment performances. Also, as the years went by, more stringent regulations concerning landfill disposal were adopted to the point that more efficient solids dewatering needed to be attained.

The problem was submitted to Neyrtec Enviro Inc., the Tasster sludge press supplier. Its engineering service department offered to supply on a “no work no pay basis” (as they were already convinced in their own mind of the superior performance to be obtained) a tapered shaft screw to be installed on one unit. Within hours after the first retrofit was completed, the anticipated results were confirmed as throughputs and cake solids were 20% to 40% higher than any results previously recorded with the older screw configuration. Based on these results, mill management shortly afterwards ordered the second unit retrofitted with the same design tapered shaft screw. The project has now been completed and the mill continues to benefit from these excellent performances. Another recorded benefit is a reduction in fibre losses.