Abstract
The objectives of this study were to evaluate the amount of phosphorus and metals in sludge that can be released into solution by microwave irradiation when applied to sludge before anaerobic digestion and determine the effectiveness of subsequent lime precipitation. The fraction of phosphorus in the soluble form increased to 23 to 28% for thickened sludge and to 31 to 38% for unthickened sludge, after raising temperatures by microwave heating to 50 to 70°C. Microwave irradiation also caused the release of arsenic, molybdenum, nickel, and selenium into solution to 33, 15, 13, and 28% for thickened sludge and 63, 61, 37, and 27% for unthickened sludge, respectively. Microwave irradiation has been found to destruct pathogens in sludge to meet Class A biosolids requirements. Therefore, the reduction of phosphorus and metals in biosolids using microwave heating is economically attractive when considered as a secondary benefit to the use of microwave heating to generate Class A biosolids.
Original language | English |
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Pages (from-to) | 784-795 |
Number of pages | 12 |
Journal | Water Environment Research |
Volume | 80 |
Issue number | 9 |
DOIs | |
Publication status | Published - 2008 Sept |
Keywords
- Biosolids
- Enhanced biological phosphorus removal
- Heavy metals
- Microwave irradiation/heating
- Primary sludge
- Waste activated sludge
ASJC Scopus subject areas
- Environmental Chemistry
- Ecological Modelling
- Water Science and Technology
- Waste Management and Disposal
- Pollution