Sloped screen separators can remove solids from liquid manure at high rates.
The manure in this system flows as a sheet over bar slats or a wedge wire screen.
The liquid passes through the slats or screen and solids are collected and slide down the sloped separator . The liquid that flows through is usually pumped to secondary separations, lagoons, and/or other manure storages. The separated solids accumulate on the lower part of the screen and then slide off periodically. These separated solids can be directly deposited on a pad or stacked by a conveyor or an auger.
Sloped screen separation is the preferred separation method when manure has a dry matter content between 2 – 4%.
Sloped screen separators are recommended for flushed manure from a freestall barn, wastewater from milking centers, and flushed swine manure from a recharge pit. Sloped screen separators are applicable when the dry matter content is greater than 5% and they are less effective than sedimentation or centrifuge when the dry matter content is less than 2%.
The screen catches almost all large fibrous particles (size greater than 0.02 – 0.1 inches, depending on the screen) from liquid manure (2 – 4% dry matter). Without separation, these large particles would enter the manure storage and take a long time to biologically degrade. By removing large particles, a sloped screen separator can reduce sludge buildup and mitigates odor generation from manure storage.
At the same time, this operation saves labor and energy costs associated with manure agitation, removal from storage, and land application (cost saving from land application assumed the screened solids will be reused as bedding).
