Investigation on greenhouse gas emissions and compost dynamics during in-vessel co-composting of septage and mixed organic wastes
2020
Thomas, A. R. | Arulraj, P. R. | Kranert, Martin | Philip, Ligy
Greenhouse gas emission during composting process is inevitable, although it relies on natural degradation. A good balance on carbon-to-nitrogen (C/N) ratio as well as the aeration mode could significantly control the emissions. The C/N ratio can be adjusted using optimal feedstock composition. The aeration can be done using passive and active modes. In the present study, greenhouse gas emissions during in-vessel co-composting of septage and organic waste with active and passive modes of aeration were investigated. This fills the gap in implementing suitable septage treatment practice. Retention of high temperature (> 55 °C) for prolonged period ensured the compost hygienization. The active aeration system showed significantly lower greenhouse gas emission compared to that of passive system. The contribution of CH₄ and N₂O to the total greenhouse gas was estimated to be 2.5% and 7.4% in the passive and 0.9% and 3.8% in the active aeration modes while > 90% was CO₂. The resulted compost maturity was confirmed by seed germination index (> 80%) and NO₃⁻/NH₄⁺ index (> 6.25). Our study highlight that in-vessel co-composting with active aeration is a suitable option to convert waste to a nutrient-rich fertilizer in a shorter period compared to other septage treatment options.
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