Table 2.
Pool (mg kg−1) of total, CaCl2 extractable and TCLP leachable heavy metals of the biowastes before and after pyrolysis.
| Pool | Material | Cu | Zn | Pb | Cd |
|---|---|---|---|---|---|
| Total | UWS | 4.02 ± 0.09 b | 14.83 ± 0.31 b | 0.95 ± 0.05 b | 0.07 ± 0.02 b |
| WSB | 13.63 ± 0.00a | 48.67 ± 3.91a | 3.19 ± 0.38a | 0.17 ± 0.00a | |
| USM | 649.4 ± 40.13 b | 4136.3 ± 9.09 b | 0.95 ± 0.04 b | 0.34 ± 0.01 b | |
| SMB | 1434.0 ± 31.6a | 6881.3 ± 89.3a | 4.23 ± 0.42a | 0.43 ± 0.02a | |
| USS | 1353.0 ± 74.1 b | 1161.4 ± 38.1 b | 389.6 ± 12.6 b | 24.69 ± 2.34a | |
| SSB | 1857.0 ± 29.8a | 2069.9 ± 46.7a | 518.7 ± 4.34a | 16.67 ± 0.31 b | |
| CaCl2 | UWS | 0.61 ± 0.04a | 1.16 ± 0.00a | 0.08 ± 0.00a | 0.05 ± 0.00a |
| WSB | 0.05 ± 0.00 b | 0.11 ± 0.01 b | 0.07 ± 0.00a | 0.03 ± 0.00 b | |
| USM | 165.2 ± 3.54a | 222.5 ± 6.01a | 0.43 ± 0.00a | 0.09 ± 0.00a | |
| SMB | 0.76 ± 0.08 b | 2.03 ± 0.03 b | 0.26 ± 0.02 b | 0.09 ± 0.00 b | |
| USS | 5.13 ± 0.00a | 40.25 ± 0.42a | 0.03 ± 0.00a | 0.27 ± 0.02a | |
| SSB | 0.05 ± 0.00 b | 0.08 ± 0.00 b | 0.01 ± 0.00 b | 0.09 ± 0.00 b | |
| TCLP | UWS | 0.83 ± 0.03a | 4.02 ± 0.04a | 0.07 ± 0.01a | 0.01 ± 0.00a |
| WSB | 0.46 ± 0.04 b | 2.69 ± 0.49 b | 0.02 ± 0.00 b | 0.01 ± 0.00 b | |
| USM | 232.9 ± 5.01a | 1032.5 ± 37.9a | 0.04 ± 0.00a | 0.02 ± 0.00a | |
| SMB | 7.77 ± 0.26 b | 131.7 ± 1.80 b | 0.01 ± 0.001 b | 0.00 ± 0.00 b | |
| USS | 78.95 ± 1.99a | 297.0 ± 4.24a | 1.08 ± 0.02a | 2.36 ± 0.01a | |
| SSB | 4.34 ± 0.15 b | 53.86 ± 1.23 b | 0.69 ± 0.03 b | 2.07 ± 0.01 b |
Data as mean ± standard deviation. UWS, USM and USS, and WSB, SMB and SSB, wheat residue, swine manure and sewage sludge respectively before and after pyrolysis; Different lowercase letters in a single biowaste pair represent a significant difference at p < 0.05 between before and after pyrolysis (One-way ANOVA followed by Turkey test).