An original impeller design, the Curved Blade Turbine impeller (CBT) facilitates batch solid suspension applications where the need to remove all solids from the tank during a draining phase is imperative, and axial flow turbines mix the bulk of the tank until the liquid level falls below the lowest axial turbine. To mix the lower portion of the tank, the shaft can be extended to the bottom of the tank and a smaller radial flow CBT can be installed called a tickler turbine. This impeller continues to mix the remaining volume until draining completes. The swept back blade profile also permits start-up in settled bed as flat blade profiles are more likely to yield.