FORMS OF SULFUR IN SEWAGE SLUDGE

Most studies concerning the composition of sewage sludge have placed emphasis on total elemental analysis, including sulfur. This study was conducted to determine the forms of S and their relationships to other components in sludge. Analyses of the forms and amounts of S in sewage sludge produced by 11 Indiana cities showed that total S concentrations ranged from 0. 7 to 2. 1% and that from 1 to 27% of the total sludge S was inorganic S extractable with 0. 1M LiCl. Expressed as a percentage of total S, the sludge samples contained from less than 1 to 35% sulfide S, from 18 to 53% inorganic nonsulfate S, from 18 to 56% carbon-bonded S, from 0 to 35% ester sulfate S and inorganic sulfate S, and from 0 to 42% unidentified organic S.