Recovery of Nutrients from Anaerobic Co-digestion Effluents of Poultry Manure and Sewage Sludge as Struvite
Abstract:Nutrient recovery from effluents of an anaerobic digestor co-digesting poultry manure and sewage sludge via struvite precipitation was successfully demonstrated. A set of mesophilic anaerobic batch reactors were operated using poultry manure and sewage sludge as the substrates. The struvite precipitation experiments were conducted with the liquid phase of these reactors. The total COD removals and the methane yields of the reactors ranged between 43–63 % and 146–228 mLCH4/gCOD added, respectively. The effects of pH, seeding and calcium on struvite precipitation process were investigated. The results revealed that high NH4–N recovery efficiencies (77 – 84 %) were possible by the adjustment of struvite stoichiometry (Mg:N:P of 1:1:1) in the reactors effluents. It was also observed that the final pH adjustment did not result in any significant increase in the removal of NH4–N at the pH levels tested (8.0, 8.5 and 9.0). Moreover, the seeding material addition was investigated to improve the performance of struvite formation by providing the adequate surface for reaction. The impact of seeding on residual NH4–N concentration was negligible, however its impact on residual PO4–P concentration was significant and highly dependant on the composition of the wastewater used. Calcium concentration in the effluents was much higher than other metal concentrations and its effect on struvite precipitation was investigated through varying the Mg:Ca molar concentration ratio. The results indicated that Ca has inhibitory effects of the struvite reaction. The presence of Ca led to formation of calcite and amorphous calcium phosphates that were detectable through XRD. The results depicted that the addition of Mg ion above the molar concentration of PO4–P together with Ca ion helped to remove most of the phosphorus even in low phosphorus wastewaters.
Document Type: Research Article
Publication date: January 1, 2011
More about this publication?
- Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.
- Subscribe to this Title
- Membership Information
- About WEF Proceedings
- WEFTEC Conference Information
- Ingenta Connect is not responsible for the content or availability of external websites