Ammonia emissions from the composting of different organic wastes. Dependency on process temperature

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

“…The majority of N losses could therefore be explained by ammonia emissions and N2 losses (Table 4.2). It is well known that temperatures above 45 °C increase ammonia volatilisation dramatically (Pagans et al, 2006). In this experiment, the thermophilic phase (> 45 °C) lasted for more than three weeks (Fig.…”

“…Controlling the pH using additives is another option for minimising ammonia volatilisation from composting because pH > 9 increases the production of ammonia (Pagans et al, 2006). The use of NH4 + absorbents such as active carbon, biochar and zeolite has also been recommended to mitigate N losses from composting (Steiner et al, 2010;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). Many studies have shown that more than half of total N losses occur during the thermophilic stage of composting (Pagans et al, 2006;Dias et al, 2009).…”

“…High temperatures (> 45 0 C) shift the NH4 + = NH3 equilibrium towards ammonia (Pagans et al, 2006). The addition of N-rich substrate at the beginning of composting increases N losses due to the combination of labile N and high temperatures during the thermophilic phase, which is a conducive environment for ammonia volatilisation.…”

“…the thermophilic phase, are essential for compost sanitisation. High temperatures (> 45 o C) shift the NH4 + = NH3 equilibrium towards ammonia (Pagans et al, 2006) and inhibit nitrification, both of which increase ammonia volatilisation. Poultry manure has a high NH4+ concentration, implying that composting of municipal waste with poultry manure may increase ammonia volatilisation, and thereby result in high N losses.…”