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Advanced treatment of liquid swine manure using physico-chemical treatment

Chelme-Ayala, Pamela, El-Din, Mohamed Gamal, Smith, Richard, Code, Kenneth R., Leonard, Jerry
Journal of hazardous materials 2011 v.186 no.2-3 pp. 1632-1638
ammonia, carbon, chlorides, coagulation, coliform bacteria, flocculation, iodine, ions, leaching, nitrates, nitrites, oxidants, oxidation, pH, phosphates, pig manure, polymers, sludge, total suspended solids
In this study, liquid swine manure was treated by physico-chemical treatment, including coagulation, flocculation, and sedimentation followed by an oxidation step as a polishing treatment at a bench-scale level. A superabsorbent polymer (SAP) and a mineral and salt formulation able to generate molecular iodine were used as coagulant and oxidant agents, respectively. The results indicated that SAP at a concentration of 1.25g/L was able to reduce 32% of the initial total suspended solids (TSS) in experiments using supernatant at its natural pH. Following the SAP application, 82% of initial ammonia (NH₃), 78% of initial total organic carbon (TOC), and 93% of the total coliforms were reduced using 40mg/L of free iodine. In experiments performed with diluted supernatant (five-fold dilution), it was found that SAP at a concentration of 0.5g/L was capable of reducing 80% of the initial TSS in experiments at pH 11. A leaching study was conducted to assess the safety of sludge disposal. From the leaching tests using non-diluted supernatant, it was found that 24% of the chloride (Cl⁻) and 50% of the phosphate (PO₄ ³⁻) ions retained in the sludge leached to the ultrapure water after 48h. Potential contamination due to leaching of NH₃, nitrite (NO₂ ⁻) and nitrate (NO₃ ⁻) was found to be statistically insignificant.