ARS | Publication request: SOLIDS AND NUTRIENT REMOVAL FROM SWINE WASTEWATER USING POLYACRYLAMIDES

Submitted to: American Society of Agricultural Engineers Meetings Papers
Publication Type: Proceedings
Publication Acceptance Date: August 5, 1996
Publication Date: N/A

Interpretive Summary: When farm land is available for manure application or manure can be sold or fed, animal producers need to conserve nutrients. Many swine production operations keep the houses clean by flushing with water. Mechanical separation of manure solids and organic nutrients contained in the very diluted wastewaters is very inefficient, 5 to 20%. Polyacrylamide (PAM) polymers were shown to be very effective for flocculating suspended solids and separating nutrients from flushing effluents. Removal efficiencies of about 80% of suspended solids, organic N, and P were obtained with relatively small PAM application rates of 25 to 100 mg/L. Solids and nutrient separation before the waste enters typical lagoon treatment provides new alternatives for waste disposal. The solids can be composted, processed for refeeding, or transported to nutrient deficient cropland.

Technical Abstract: Assigning nutrients to nutrient deficient areas through solids separation is critical to overcome current land limitations associated with large swine operations in the Southeast region. Mechanical separation with screens can remove only 5 to 20% of the total suspended solids (TSS), organic N, and P. Our evaluation of various polyacrylamide (PAM) polymers showed that cationic PAM with a 20% charge density is very effective for flocculating TSS and separating nutrients from flushing effluents. Removal efficiencies of about 80% of TSS, organic N, and P were obtained with PAM rates of 25 to 100 mg/L and swine wastewater having 3.2 to 6.8 g/ L total solids content.