If your water or wastewater treatment plant is like thousands of others in the U.S., you are operating a gravity belt thickener and/or belt filter press to thicken or dewater residuals and biosolids. For many, these machines may have originally been purchased 20, 30 or even 40 years ago (and probably from Ashbrook Simon-Hartley). In this article we are going to take the guesswork out of how you can breathe life back into these machines, what improvements can be made, and how the process works so that you can decide if it’s the right choice for your process.