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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #310864
Title: A novel treatment system to remove phosphorus from liquid manure

Author
item Church, Clinton
item HRISTOV, ALEXANDER - Pennsylvania State University
item Bryant, Ray
item Kleinman, Peter
item Fishel, Sarah - Sarah K Marshall

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2015
Publication Date: 1/30/2016
Citation: Church, C., Hristov, A.N., Bryant, R.B., Kleinman, P.J., Fishel, S.K. 2016. A novel treatment system to remove phosphorus from liquid manure. Applied Engineering in Agriculture. 32(1):103-112. doi: 10.13031/aea.32.10999.

Interpretive Summary: Removing phosphorus from animal manure is one approach of addressing concerns over surplus phosphorus accumulation on farmlands. We developed a novel treatment system for liquid manures that conserves manure nitrogen while removing most of the manure phosphorus. When tested on manure slurries from 150 and 2700-cow dairies, 96 to 99% total phosphorus was removed along with 92 to 94% of the solids, resulting in liquid manure filtrates with nitrogen:phosphorus ratios greater than 19:1. Results suggest that this system coud be used on small and large operations alike.

Technical Abstract: Lowering the total phosphorus (P) content of animal manure is one approach of addressing concerns over surplus P accumulation in soils resulting from land application of animal manure. We sought to develop a treatment system for liquid manures that conserves manure nitrogen (N) while removing most of the manure P. Initial evaluation of a treatment system involving manure solid separation and precipitation of dissolved P with an alkaline salt (Ca(OH)2) resulted in poor liquid/solid separation and poor dissolved P removal and created conditions promoting ammonia-N (NH3-N) volatilization. As a result, we developed a three-stage system with iterative solid removal and acid salt (ferric sulfate – Fe2(SO4)3) sorption of dissolved P: (1) removal of bulk and intermediate sized solids (>25 um); (2) chemical treatment to convert dissolved P; and (3) final removal of fine solids and chemically sorbed P. When tested on manure slurries from 150 and 2700-cow dairies, 96 to 99% total P was removed along with 92 to 94% of the solids, resulting in liquid manure filtrates with N:P ratios greater than 19:1. While costs of treatment were roughly $38 kg**-1 P removed, equivalent to $750 cow**-1 yr**-1, we anticipate that refinement of the process and beneficial uses of the solid materials (bedding, compost, etc.) will improve cost-efficacy considerably.