In terms of nitrogen (Fig. 4B), it was found that
treatments applied with nutrient supplements, the initial
value was 106.23 mg L-1 as compared to treatments with no
nutrient supplement (22.8 mg L-1). This study showed that
treatments applied with nutrient supplements, nitrate had a
high value and was quite consistent from the start of the
experiment until day 8. This was because ammonia was
oxidized to nitrate until ammonia in the wastewater began to
disappear and algae started to use nitrogen in the form of
nitrate such that the amount of nitrate decreased rapidly
after day 8. At the final stage of the experiment, nitrate was
measured as 11.36 mg L-1 with an efficiency rate of
reducing nitrogen at 49% as compared to treatments applied
with no nutrient supplements, which had only a slight
decrease and the lowest value at day 6 (10.11 mg L-1) with
an efficiency value of reducing nitrogen at 54%.