This is a good question and one that we get asked a lot. The answer to it really depends on what you are trying to accomplish.
A screen with openings 1/8” and larger is considered a coarse screen and is used to primarily remove the larger manure particles. This screen would be used if you’re trying to keep some material out of your lagoon, or maybe you’re looking to make some green bedding and you’re also using a Roll Press. In either case, this screen would remove the larger particles, but the overall capture of fibers would be relatively low, most likely less than 20%. If you’re looking to remove as much material as possible to create clean process water, we would recommend the 18 mesh screen. This has the smallest openings for our standard screen offering and also produces the cleanest process water. The overall removal of fibers with this screen could be as high as 45%. This 18 mesh screen is also a great option if a high removal rate is necessary before putting the manure through a nutrient separation system. Roll Presses are often used to dewater the thickened material coming off the Rotary Screen. If an 18 mesh screen is used, the Roll Press will have more difficulty dewatering the material due to the large amount of fine fibers that are present.
Feel free to contact our Engineering Department if you still have questions about selecting the appropriate screen for your Rotary Drum.