This suspended solids density meter helps municipal and industrial plants monitor concentrations in pipelines and tanks and automate sludge removal. It uses the safe attenuation of non-radioactive ultrasound to read concentrations, and requires no permits or approvals. In municipal and industrial wastewater settings, the meter monitors sludge concentration in pipelines, clarifiers, sand or membrane filters, and tanks. In municipal water treatment plants, it is used to monitor backwash sludge.