The changes in dissolved oxygen (DO) levels for the EM bioremediation,
MA phytoremediation and symbiotic MAeEM bioremediation
modes were shown in Fig. 3. In EM bioremediation
mode, the DO drops instantaneously to almost 0 mg L1 within the
first 3 days of the treatment period. Similar pattern could be
observed in the symbiotic MAeEM bioremediation mode, however
the decrease in DO was more gradual where the minimum DO
levels achieved were 2.23, 2.32 and 2.68 mg L1 at the inoculation
of 20%, 30% and 40% MA with 3 mL EM, respectively. In the MA
phytoremediation mode, DO levels fluctuated throughout the
treatment period. The neutralization of the acidic pH of the
wastewater was consistent for all modes of bioremediation. For the
EM bioremediation mode, the pH increase from 4.4 to 7.5 within 14
days whereas the increase of pH for MA phytoremediation and
symbiotic MAeEM bioremediation were evidenced at 4e7 days of
treatment period.