Economic and Environmental Manure Solutions

solids separations

Technology Description (from Hartzell, 2001 and Dougherty et. al. 1998)
Solids separation (or de-watering) is the process of separating the liquids and solids portions of manure from one another.  Solids separation can take place in two ways:  mechanical separation (active) and gravity settling (passive).  Mechanical solids separation (the focus of this site) can be accomplished using a number of different means including screw presses, roller presses, and vibrating screens.  In these technologies, the liquids portion of the manure passes through the screens while the solids portion is retained on the front of the screen (where it is then moved).  The products of mechanical separation are an easily handled solid and a readily pumped liquid. 

Separated solids can have a solids content ranging from 12% to 40% (depending upon the system) compared to un-separated manure that has a typical solids content of 8%.  Higher solids content for the solids portion of manure results in a more stackable and managed product that can be composted and sold, reused as bedding or feed, or more easily transported to distant areas for direct application compared to un-separated manure.

Separated liquids have a lower solids content compared to un-separated manure (as low as 4%) which make them more pumpable and suitable for irrigation equipment than un-separated manure.  Application via irrigation equipment can be more advantageous than application via traditional manure spreaders due to more flexible application times and frequencies, less labor, and less soil compaction (increased yields).  

Sources of Additional Information
Case studies and guidebooks for solids separation including “Liquid Manure Application Systems Design Manural” NRAES-89 (which contains a list of solids separation equipment manufacturers) and Dairy Manure System:  Equipment and Technology NRAES-143 can be purchased from NRAES at www.nraes.org  

Several solids separation vendor presentations are also provide in the Conferences section of this website under the December Conference.

References
Hartzell, K.  “Liquid-Solid Separation.”  Proceedings from “Dairy manure Systems:  Equipment and Technology” Rochester, NY  March 20-22, 2001  NRAES Publication No. NRAES-143  pp. 127-134

Dougherty, M., L.D. Geohring, and P.E. Wright.  “Liquid Manure Application Systems Design Manual” NRAES Publication No. NRAES-89  1998 Cooperative Extension 152 Riley Robb Hall Ithaca, NY 14853-5701

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Cornell University

Department of Biological and Environmental Engineering

Ithaca, NY 14853

Fax: 607.255.4080