The Suspended Solids Density Meter from Markland Specialty Engineering monitors sludge and silt concentrations in pipes, clarifiers and tanks and helps automate biosolids removal. Using ultrasound, it measures primary, secondary, return-activated and backwash sludge. It allows users to program underflow pumps to automatically shut off before sludge becomes too thin and helps operators determine polymer dosages for improved filter press/centrifuge/digester performance. The in-line pipe spool-piece sensor is nonintrusive and simple to install, calibrate and clean. 855/873-7791; www.sludgecontrols.com.