If you are referring to "sludge," yes you would need the solids content.  In other words, a short (2000 lbs) ton of wet sludge might contain only 200 lbs of dry solids, if it was 10% solids.

0.10 x 2000 wet lbs = 200 dry lbs of solids

Converting US tons (2000 lbs) to metric tons, where a metric ton is 2205 lbs.:    

1216.62 wet short tons at say 10% solids = 121.662 tons of dry solids

121.662 short tons x 2000/2205 = 110.35 MT

But, you'll need the solids content to get the correct answer.