The ENVISTA Vis advanced polymer optimization system from Kruger USA determines and controls the optimum polymer dose for biosolids dewatering operations. The system consists of integral auto sampling, sample conditioning and sample dilution components. It automatically accounts for the variability in feed sludge quality typical at many wastewater treatment plants. It measures the absorbance of light in a diluted sample of dewatered centrate or pressate at regular intervals. A characteristic parabolic curve of absorbance is developed that correlates with the concentration of residual polymer in the sample. The system then automatically adjusts the plant’s polymer system to feed the optimum dose. Full-scale testing has demonstrated a polymer savings of 30 percent without any negative impact on final cake solids. It reduces operator attention and manpower by automating polymer-dosing adjustments while producing a consistent, high-quality end product. 919/677-8310; www.krugerusa.com.