At a polymer manufacturing plant on the Monsanto Antwerp site in Belgium, a solid bowl decanter centrifuge is used to recover acetates from polymer slurry. An internal washing is applied on the conical beach to improve the recovery of the acetates. To increase capacity, the original centrifuge with a single lead conveyer was replaced by a centrifuge with a double lead conveyer. During the optimization of the performance of this centrifuge, it was shown that there is an optimum pool depth for the efficiency of the displacement wash taking place on the beach of the centrifuge. The introduction of another double-lead conveyer with a reduced pitch resulted in further improvement in the acetate yield.