title: Stability of enhanced biological phosphorus removal and composition of polyphosphate granules.
abstract: The influence of varying Ca- and Mg-concentration of the influent wastewater on the enhanced biological phosphorus removal was investigated in an anaerobic-aerobic bench-scale plant. The artificial enhancement of the Mg-concentration in the influent from 15 to 24 mg l(-1) and 31 mg l(-1), respectively, caused a raise of the mean P-removal efficiency from 85 to 97%. The P-elimination was very stable in time. A chemical precipitation of magnesium ammonium phosphate could be excluded. The elemental composition of polyphosphate granules was investigated by electron microscopy and energy dispersive X-ray spectroscopy. The elements Ca, Mg and K were the principal metal components of polyphosphate granules. Concerning the metal composition, different types of granules could be distinguished. The quantitative ratios of Ca, Mg and K varied in dependence on the influent concentration of these metals. A relation between the Mg/Ca-ratio of the granules and the efficiency of enhanced biological phosphorus removal can be supposed.
authors.affiliation: Institute for Solid State and Materials Research, Dresden, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Schönborn
authors.forename: H D
authors.initials: HD
authors.lastname: Bauer
authors.forename: I
authors.initials: I
authors.lastname: Röske
mesh_terms: D002118:Calcium / Q000032:analysis; D008274:Magnesium / Q000032:analysis; D008854:Microscopy, Electron; D010100:Oxygen / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry* / Q000302:isolation & purification*; D011108:Polymers / Q000737:chemistry; D011122:Polyphosphates / Q000737:chemistry* / Q000302:isolation & purification*; D011188:Potassium / Q000032:analysis; D012722:Sewage / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D014865:Waste Disposal, Fluid
chemical_list: D011108:Polymers; D011122:Polyphosphates; D012722:Sewage; D010758:Phosphorus; D008274:Magnesium; D011188:Potassium; D010100:Oxygen; D002118:Calcium