compared to those obtained under the same conditions at discontinuous
operation mode.
3.2. Bioremediation of swine slurry: batch vs. semi-continuous
cultivation
Bioremediation of swine slurry using microalgae biomass was
studied by evaluating the nutrient removal, i.e. NH4
þ and PO4
3.
Ammonium was removed by 96e99% for all tested conditions after
10 days (Fig. 2D, E, F). This removal was faster when working under
summer conditions at high NH4
þ load than during non favourable
conditions, being 94% of the ammonium eliminated after 6 days
and totally removed after 10 days. In the case of low NH4
þ load, no
remarkable differences were observed (Fig. 2E).
In order to elucidate the fate of NeNH4
þ under different scenarios,
the main mechanisms (namely ammonia stripping, uptake
and nitrification) involved in ammonium removal were studied. It
was observed that the initial NeNH4
þ load determined the main
removal mechanism in each case, thus, ammonia stripping and
nitrogen uptake accounted similarly in the case of high NH4
þ load,
while nitrogen uptake prevailed at low NH4
þ load.