Potential of aeration flow rate and bio-char addition to reduce greenhouse gas and ammonia emissions during manure composting

Closing the nutrient loops in (peri-)urban farming systems through composting

“…Ammonia volatilisation occurs mainly during the thermophilic phase of composting (Chowdhury et al, 2014). Similarly, Eklind et al (2007) showed that higher temperatures (i.e., 67 °C) increase ammonia loss by more than 100% compared to lower temperatures (i.e., 40 °C).…”

“…Mg -1 fresh weight during garden waste composting (Anderson et al, 2010). Most CH4 emissions occur during the thermophilic stage of composting due to the coexistence of labile carbon compounds and anoxic microsites (Anderson et al, 2010;Chowdhury et al, 2014), and the activity of methanogens increases at high temperatures (Ermolaev et al, 2014). Chowdhury et al (2014) and Vu et al (2015) showed that more than 70% of CH4 production occurs during the thermophilic phase.…”

“…Most CH4 emissions occur during the thermophilic stage of composting due to the coexistence of labile carbon compounds and anoxic microsites (Anderson et al, 2010;Chowdhury et al, 2014), and the activity of methanogens increases at high temperatures (Ermolaev et al, 2014). Chowdhury et al (2014) and Vu et al (2015) showed that more than 70% of CH4 production occurs during the thermophilic phase. On the other hand, N2O is emitted after the thermophilic stage because nitrifying and denitrifying bacteria are mesophilic (Hao et al, 2004;Vu et al, 2015).…”

“…Reducing nitrogen losses and GHG emissions are among the main challenges of the composting process because these losses reduce the fertilising value of compost and contribute to climate change. Ammonia volatilisation is the major N loss from compost and accounts for over 60% of total N losses (Dias et al, 2009;Chowdhury et al, 2014).…”

“…Several technologies, such as the addition of crop residues (Santos et al, 2016;Vu et al, 2015), the control of aeration rate (Chowdhury et al, 2014) and the control of pH (Awasthi et al, 2016) (section 1.2. ), are suggested as ways of reducing N losses and GHG emissions from composting.…”