In most indoor RAS, ammonia removal and solids capture are
the primary treatment processes within the recirculation loop.
Although intended to collect or convert fish waste, these online
treatment processes might lead to a considerable waste reduction
through production of mainly gaseous carbon and nitrogen compounds
by biological decay. The extent of this decay, mainly due
to heterotrophic microorganisms, largely depends on the specific
system configuration
In particular, the water and solid retention
time of the system as well as methods used for water treatment
within the recirculating loop are major factors underlying such
heterotrophic bacterial activity
The loss of nitrogen is mainly
due to denitrification in oxygen depleted zones in the system and
may account for as much as 21% of the nitrogen loss in some RAS