There was no significant decrease in ts,
ds, or vs after ozonation. This indicated
that complete oxidation of organic content
to carbon dioxide and water did not occur
to any appreciable extent. In fact, in most
cases, the solids showed an increase after
ozonation. This increase was mostly a
result of the addition of sulfuric acid or
sodium hydroxide, which was added to
adjust the pH of the sample before ozoniza
tion