Sewage sludge for cultivating fresh water algae and the fate of heavy metals at higher trophic organisms 1. different methods of extracting sewage sludge on the properties of sludge extracts
Tam, F.Y.; Wong, M.H.
Archiv fur Hydrobiologie 96(4): 475-485
ISSN/ISBN: 0003-9136 Accession: 006405643
Different methods were employed to extract sewage sludge. Autoclaving was the most effective method in recovering essential nutrients and heavy metals from sewage sludge, followed by snaking; homogenizing was the least effective. The pH of the extractant was the main factor in determining the content of heavy metals in sludge extracts; the 2 extreme pH (2 and 12) yielded extracts with higher essential nutrients. The amount of heavy metal released was negatively correlated with the extractant pH.