Biological Reduction of Perchlorate from Spent Modified Reed Mediated by an Enriched Microbial Culture

Table 3

Environmental parameters for the biological removal of perchlorate, ClO₄⁻, from spent MR with EMC over 7 d at 25°C.

Parameter time point	System #1 EMC (St) + ClO4^−	System #2 EMC + ClO4^−	System #3 EMC + aq. ClO4^−	System #4 EMC (no ClO4^−)
pH
Initial	6.99 ± 0.12	7.12 ± 0.18	7.08 ± 0.10	7.23 ± 0.11
Final	6.32 ± 0.08	6.02 ± 0.05	6.65 ± 0.11	6.73 ± 0.08
ORP^++ (mV)
Initial	287.68 ± 3.71	277.70 ± 3.54	318.92 ± 5.99	282.87 ± 0.23
Final	320.72 ± 0.581	335.60 ± 0.67	345.59 ± 0.83	310.55 ± 0.23
DO (mg/L)
Initial	0.69 ± 0.03	0.47 ± 0.03	0.52 ± 0.09	0.41 ± 0.02
Final	BD	BD	BD	BD

Notes. Data are means from experiments performed in triplicate reported with standard deviations. Final measurements taken 7 d (at 25°C) after initial measurements. Initial [ClO₄⁻] = 30 mg/mL, equilibrated with MR; [MR] = 2 g/L. Abbreviations: aq., aqueous; BD, below detection; DO, dissolved oxygen; EMC, enriched microbial biomass; MR, modified reed; ORP, oxidation-reduction potential; (St), sterilized.