Utilize este identificador para referenciar este registo: http://hdl.handle.net/10348/7948
Título: Delayed application of N-rich substrate affects GHG emissions during composting
Autor: Mota, Ana Cláudia Simões da
Orientador: Kuyper, Thom
Nigussie, Abebe
Trindade, Henrique
Palavras-chave: Compostagem
Gases com efeito de estufa
Data: 2016
Resumo: A significant amount of nitrogen (N) is lost during composting and this loss reduces the fertilizing value of the final product. Greenhouse gas emissions (GHG) – mainly methane (CH4) and nitrous oxide (N2O) – also occur during composting. High temperatures (> 45°C) increase ammonia volatilisation. The addition of an N-rich substrate after the thermophilic phase (late addition) is therefore proposed as a way of reducing nitrogen losses and GHG emissions from composting thereby improving the agronomic value of the final product. Vermicomposting – composting by earthworms – has also been suggested for reducing N losses from composting. However, the effect of these practices on the GHG emissions is unclear. The objective of this thesis was, therefore, to investigate the effect of delayed addition of N-rich substrate on greenhouse gas emissions during composting and link this effect to the different composting method. The results showed that the treatments with early addition increased CO2 production (P = 0.03), irrespective of the composting method. Apart of the mixing ratios of the substrate, vermicomposting increased the CO2 emissions by 22 - 47% compared with traditional composting (P < 0.01). Vermicomposting also increased N2O emissions (P = 0.01) by 160 – 230%, but decreased CH4 emissions (P = 0.01) from 97-253%. The timing of substrate addition on GHG emission showed the same pattern regardless the composting methods. Delayed addition increased N2O emissions, but reduced CH4 production. With vermicomposting, the NO3- concentrations increased from 90%-140% and the NH4+ concentrations decreased by 23 – 44% except in the 3rd treatment where it increased 98%. The pH dropped ( 0,5 – 3%) in the presence of earthworms. In conclusion, the timing of addition of N-rich substrate influences the total GHG emissions and chemical properties of compost and hence further studies are suggested to understand the mechanisms.
Descrição: Dissertação de Mestrado em Engenharia Agronómica
URI: http://hdl.handle.net/10348/7948
Tipo de Documento: Dissertação de Mestrado
Aparece nas colecções:TD - Dissertações de Mestrado

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