10.6084/M9.FIGSHARE.C.6227513.V1
Theresa Constanze Sichler
Theresa Constanze
Sichler
Federal Institute For Materials Research and Testing
Roland Becker
Roland
Becker
Federal Institute For Materials Research and Testing
Andreas Sauer
Andreas
Sauer
Federal Institute For Materials Research and Testing
Matthias Barjenbruch
Matthias
Barjenbruch
Technical University of Berlin
Markus Ostermann
Markus
Ostermann
Federal Institute For Materials Research and Testing
Christian Adam
Christian
Adam
Federal Institute For Materials Research and Testing
Determination of the phosphorus content in sewage sludge: comparison of different aqua regia digestion methods and ICP-OES, ICP-MS, and photometric determination
Abstract Phosphorus recycling from sewage sludge will be obligatory in Germany from 2029. Phosphorus content determination in sewage sludge is crucial to assess the prescribed recycling rates. Currently, German law regards sample preparation using aqua regia digestion in a microwave or under reflux conditions as well as instrumental phosphorus determination by ICP-OES, ICP-MS, or photometric determination with ammonium molybdate as equivalent. However, it is questionable whether these methods are indeed equivalent regarding phosphorus quantification in sludges near the limit of 20 g/kg for mandatory recycling. To answer this question, 15 sewage sludges of 11 different wastewater treatment plants were investigated with all permitted method (digestion and measurement) combinations. Moreover, one sewage sludge was also examined in an interlaboratory comparison (ILC) with 28 participants. This study shows that the above-mentioned methods differ in some cases significantly but across all method combinations and sludges, phosphorus recovery was between 80 and 121% after normalization to the grand mean (average of 15 sludges between 85 and 111%). The ILC and the examination of 15 sludges produced largely similar results. There is a tendency to higher phosphorus recovery after microwave digestion compared to reflux digestion and ICP-OES measurements determine higher phosphorus contents than ICP-MS and photometric phosphorus determination. As a result, the authors recommend ICP-OES determination of phosphorus in sewage sludge after microwave digestion. Graphical Abstract
Medicine
Cell Biology
Biotechnology
39999 Chemical Sciences not elsewhere classified
Ecology
Immunology
Cancer
Plant Biology
figshare
2022
2022-10-02
2022-10-02
Collection
10.1186/s12302-022-00677-1
10.6084/m9.figshare.c.6227513
CC BY 4.0