SE—Structures and Environment: Effect of Batch Aeration-Treatment on the Solubility of Phosphorus in Pig Manure

✍ Scribed by P.M. Ndegwa; J. Zhu; A. Luo

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 227 KB
• Volume: 80
• Category: Article
• ISSN: 0021-8634
• DOI: 10.1006/jaer.2001.0745

✦ Synopsis

Experiments were conducted to investigate the e!ect of temperature on phosphorus removal from pig manure during batch aeration and the mechanism(s) involved in its removal. Five temperature regimes, 5, 10, 15, 20 and 253C, were investigated. The resulting e!ects on pH, volatile fatty acids levels (VFAs), and ortho-phosphate (ortho-P) in the manure were investigated. Results indicated that manure pH was the dominant factor in#uencing the levels of soluble ortho-P in the manure. Two di!erent mechanisms that e!ected pH change were identi"ed. Immediately after initiating aeration (i.e. during the "rst 1)5 days*phase I), a rapid rise in pH caused a rapid decline in manure-soluble ortho-P (coe$cient of determination R of 0)90). The manure pH beyond the "rst 1)5 days (phase II aeration) seemed to depend more on the VFAs levels. It was concluded that besides any phosphorus immobilization/release by the microbial biomass in phase II, the VFAs levels in the manure signi"cantly explained (R of 0)83) most of the biologically mediated chemical precipitation/dissolution of ortho-P. Temperature a!ected soluble ortho-P status only in phase II of aeration. High manure temperatures reduced aeration e$ciency but promoted the production of VFAs. The resulting low pH led to the redissolving of ortho-P previously precipitated in the higher pH-regime in phase I; this may potentially reduce the e$ciency of removing orthophosphates by subsequent solid}liquid separation treatments.