title: Phosphorus recovery potential from a waste stream with high organic and nutrient contents via struvite precipitation.
abstract: Recovery of NH4(+)-N and PO(3-)-P via struvite precipitation (SP) was evaluated from liquor of thermally pretreated waste activated sludge, containing high levels of nutrients (1500 mg NH4(+)-N/L and 650 mg PO(3-)-P/L), organics (45.5 g COD/L) and suspended solids (3.5 g TSS/L), with reference to anaerobically digested sludge centrate. In a series of jar tests, the order of pH adjustment and chemical addition were first tested for the digested sludge centrate. The effects of MgCl2 and MgO, as Mg2+ sources, on SP were evaluated in both waste streams. Up to 80% of the dissolved PO4(3-)-P was recovered using MgO (pH = 9.2) from the pretreated sludge liquor and more than 86% of NH4(+)-N from the digested sludge centrate (pH = 8.0-8.5) regardless of the Mg2+ source used. NH4(+)-N recovery from digested sludge centrate required the addition of alkali, Mg2+ source and PO4(3-)-P, making the process less viable. The precipitates contained mostly struvite and some levels of Ca2+, Fe2+ and other Mg2+ phosphates. The levels of solids, inorganics and organics in the waste streams influenced SP, specifically struvite crystal formation and settleability in the pretreated sludge liquor, which suggests that the applicability of SP for nutrient recovery from complex waste streams requires case-by-case testing, and process optimization.
authors.affiliation: AnoxKaldnes AB Klosterängsvägen 11A, 226 47 Lund, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Karabegovic
authors.forename: M
authors.initials: M
authors.lastname: Uldal
authors.forename: A
authors.initials: A
authors.lastname: Werker
authors.forename: F
authors.initials: F
authors.lastname: Morgan-Sagastume
mesh_terms: D000042:Absorption; D011232:Chemical Precipitation; D003247:Conservation of Natural Resources; D005590:Fractional Precipitation / Q000379:methods*; D017616:Magnesium Compounds / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry / Q000302:isolation & purification*; D000069877:Struvite; D062065:Wastewater / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D017616:Magnesium Compounds; D009930:Organic Chemicals; D010710:Phosphates; D010758:Phosphorus; D000069877:Struvite; D062065:Wastewater; D014874:Water Pollutants, Chemical