title: Efficient Phosphorus Cycling in Food Production: Predicting the Phosphorus Fertilization Effect of Sludge from Chemical Wastewater Treatment.
abstract: This study examined the P fertilization effects of 11 sewage sludges obtained from sewage treated with Al and/or Fe salts to remove P by a pot experiment with ryegrass (Lolium multiflorum) and a nutrient-deficient sand-peat mixture. Also it investigated whether fertilization effects could be predicted by chemical sludge characteristics and/or by P extraction. The mineral fertilizer equivalent (MFE) value varied significantly but was low for all sludges. MFE was best predicted by a negative correlation with ox-Al and ox-Fe in sludge, or by a positive correlation with P extracted with 2% citric acid. Ox-Al had a greater negative impact on MFE than ox-Fe, indicating that Fe salts are preferable as a coagulant when aiming to increase the plant availability of P in sludge. The results also indicate that sludge liming after chemical wastewater treatment with Al and/or Fe salts increases the P fertilization effect.
authors.affiliation: NIBIO, Norwegian Institute of Bioeconomy Research , P.O. Box 115, N-1431 Ås, Norway.
authors.forename: Anne
authors.initials: A
authors.lastname: Falk Øgaard
authors.affiliation: NIBIO, Norwegian Institute of Bioeconomy Research , P.O. Box 115, N-1431 Ås, Norway.
authors.forename: Eva
authors.initials: E
authors.lastname: Brod
mesh_terms: D005308:Fertilizers / Q000032:analysis*; D008129:Lolium / Q000254:growth & development* / Q000378:metabolism; D010758:Phosphorus / Q000032:analysis* / Q000378:metabolism; D012722:Sewage / Q000032:analysis*; D062065:Wastewater / Q000032:analysis*
chemical_list: D005308:Fertilizers; D010758:Phosphorus; D012722:Sewage; D062065:Wastewater
keywords: P extraction; aluminum; iron; mineral fertilizer equivalent; sequential fractionation; sewage sludge