Table 2 Change in physicochemical properties and metal content of the examined MSW compost samples in both pre- and post-leaching treatment (Optimum condition: 150 mM, pH 2.9, and retention time 120 min).
From: Bio-chelate assisted leaching for enhanced heavy metal remediation in municipal solid waste compost
Property | Unit | Requirement | MSW compost | ||
|---|---|---|---|---|---|
Original | GLDA treated | EDTA treated | |||
pH | 6.5–7.5 | 6.4 ± 0.04 | 6.32 ± 0.04 | 6.18 ± 0.22 | |
Conductivity | ds m−1 | ≤ 4 | 2.2 ± 0.2 | 1.79 ± 0.08 | 1.63 ± 0.21 |
Bulk density | g cm−3 | 0.7–0.9 | 0.64 ± 0.58 | 0.61 ± 0.09 | 0.61 ± 0.15 |
Total organic carbon | % by mass | ≥ 14 | 27.13 ± 0.85 | 22.34 ± 1.59 | 22.45 ± 1.77 |
Total nitrogen | % by mass | ≥ 0.8 | 1.71 ± 0.05 | 1.22 ± 0.01 | 1.14 ± 0.02 |
Total phosphorus | % by mass | ≥ 0.4 | 0.41 ± 0.02 | 0.17 ± 0.02 | 0.21 ± 0.03 |
Total potassium | % by mass | ≥ 0.4 | 0.18 ± 0.01 | 0.05 ± 0.01 | 0.19 ± 0.02 |
Cadmium (as Cd) | mg kg−1 | ≤ 5 | 21.80 ± 1.46 | 2.11 ± 0.05 | 1.29 ± 0.02 |
Copper (as Cu) | mg kg−1 | ≤ 300 | 1836.51 ± 11.65 | 331.30 ± 8.16 | 323.96 ± 11.41 |
Lead (as Pb) | mg kg−1 | ≤ 100 | 698.35 ± 8.65 | 58.52 ± 4.3 | 47.76 ± 2.33 |
Zinc (as Zn) | mg kg−1 | ≤ 1000 | 8130.73 ± 42.21 | 1598.50 ± 20.45 | 1159.44 ± 8.82 |
