Addition of wood sawdust during the co-composting of sewage sludge and wheat straw influences seeds germination.
The objective of this study was to investigate the effect of addition of sawdust co-composted with sewage sludge and wheat straw on seeds germination. Two mixtures were piled and composted over 90 days. The first mixture (C1) was composed of sewage sludge and wheat straw, while the second mixture (C2) was composed of sewage sludge, wheat straw and wood sawdust. The results showed that the physicochemical parameters of both composts, i.e., temperature (> 55 °C in the thermophilic phase), moisture content (~ 30%). pH (6.73 for C1 and 7.19 for C2) and EC values (1.81 mS cm-1 for C1 and 1.32 mS cm-1 for C2) reached the required maturity standard. The values of C/N were below 12 indicating a high degree of maturity. Also, no bacterial pathogens were detected in the final composts. The concentration of total heavy metals has been reduced allowing the elimination of sewage sludge toxicity, confirmed by the germination index, which reached over 80%. Strong positive correlations were noticed between total Kjeldahl nitrogen of C2 and germination indexes of all the studied species. The obtained results indicate that the addition of wood sawdust increases the nitrogen content leading to slightly alkaline compost which influences seeds germination by reducing the phytotoxicity of sewage sludge.
['Kebibeche|Hassiba|H|', 'Khelil|Omar|O|', 'Kacem|Mourad|M|', 'Kaid Harche|Meriem|M|']
D029741:Brassica rapa D002244:Carbon D000076282:Composting D004755:Enterobacteriaceae D004926:Escherichia coli D018525:Germination D006863:Hydrogen-Ion Concentration D031220:Lepidium sativum D018545:Lettuce D009584:Nitrogen D012499:Sanitation D012639:Seeds D012722:Sewage D012987:Soil D012988:Soil Microbiology D013289:Streptococcaceae D013696:Temperature D014908:Triticum D014934:Wood
Wood sawdust Sewage sludge Wheat straw Composting Phytotoxicity Chemical composition