| Autor: |
Taylor, J. M., Epstein, E., Burge, W. D., Chaney, R. L., Menzies, J. D., Sikora, L. J. |
| Zdroj: |
Journal of Environmental Quality; October 1978, Vol. 7 Issue: 4 p477-482, 6p |
| Abstrakt: |
Chemical and biological observations were made on sewage sludge in a simulated trenching system in the greenhouse. Limed and unlimed raw and digested sludges were placed in simulated trenches in soil profile boxes in which corn (Zea maysL.) was sown. During the 160‐day growth period, roots penetrated entrenched digested sludge and root growth proliferated throughout the sludge. Root penetration into the raw sludges was severely restricted. Gas analysis showed that anaerobic conditions prevailed for extensive periods during the 160 days in raw sludge. Methane and CO2levels reached 45 and 25%, respectively. The levels of CH4and CO2were < 3 and 21%, respectively, in the digested sludge boxes. Nitrate nitrogen, adjacent to and beneath the sludge, was generally higher with digested than with raw sludge. Zinc and copper did not move from the sludge into the surrounding soil. The increase of these metals in corn leaves was relatively low, reaching only 131 µ/g Zn and 5.9 µ/g Cu as compared with 79 µ/g Zn and 3.8 µ/g Cu in the controls. Although low levels of fecal coliforms survived in the sludge, none were found in the soil surrounding the sludge. Total coliform numbers in the sludge after 160 days were negatively correlated with NH3‐N concentrations, suggesting that NH3, generated on dissociation on NH4+, may be important in reduction of human pathogens. |
| Databáze: |
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