Influence of bulking agents on organic matter evolution during sewage sludge composting; consequences on compost organic matter stability and N availability

Influence of bulking agents on CH4, N2O, and NH3 emissions during rapid composting of pig manure from the Chinese Ganqinfen system

“…These results were similar to those of Fukumoto et al (2003) and Jiang et al (2011). The bulking agent could increase the N availability by enhancing the N organization and limiting N losses by volatilization during composting (Doublet et al, 2011), and the loss of N by volatilization was affected by the loss of C during the composting process rather than by the moisture content or aeration regime (Barrington et al, 2002), and also by the initial C/N ratio of the composting mixtures and the presence of recalcitrant carbon fractions such as lignin (Goyal et al, 2005). However, N 2 O produced by both nitrifiers and denitrifiers was optimized under microaerobic conditions (Czepiel et al, 1996).…”

“…However, the temperature in the SWD run increased rapidly after the fourth turning and then decreased gradually. The nature of bulking agents influences the time needed to reach similar organic matter (OM) stability and the biochemical evolution of OM (Doublet et al, 2011). Sawdust had the higher content of lingocellulose materials and low available carbon sources for microorganism than corn stalk and spent mushroom compost, and therefore, temperatures in the SWD run were lower than others in the first 17 d. However, after that, turning activities made the composting materials more homogeneous especially the easily degradation lignocelluloses of sawdust, which made the activities of microbes increase after Day 17 in the SMC run.…”

“…Fukumoto et al (2003) showed that a large-scale compost pile increased the emission rate of gaseous components, especially N 2 O and CH 4 . The bulking agent influenced the C dynamics during composting, which was related to their own degradability, more specifically, the nature and recalcitrance of their holocellulosic fractions (Doublet et al, 2011), so that they could influence the biodegradability of organic matter during the composting process. However, CH 4 production was not only related to the content of carbohydrates (Fukumoto et al, 2003), but more importantly to the physicochemical characteristics of the composting mixture (e.g., temperature, strict anaerobic condition, and compost structure) (Szanto et al, 2007;Beck-Friis et al, 2000;Jiang et al, 2011).…”

“…Therefore, the addition of a bulking agent is necessary to compost the separated solid fraction of pig manure (Nolan et al, 2011). A bulking agent is the material that adjusts the C/N ratio, provides optimum free air space (FAS), and regulates the water content of the waste to be composted (Gea et al, 2007;Kato and Miura, 2008;Iqbal et al, 2010;Jolanun and Towprayoon, 2010;Doublet et al, 2011), which are usually fibrous with carbonaceous material (Iqbal et al, 2010). The bulking agent represents a large proportion of the composting mixture as a source of carbon and energy for micro-organisms (Adhikari et al, 2009).…”

Composting of olive processing wastes and tomato stalks together with sewage sludge or dairy manure

“…Fernández et al (2010) and Sánchez-Arias et al (2008) achieved fruitful results through co-composting sewage sludge with plant and animal based wastes. Hygienization as well as reduction in volume and the amount of sludge through composting are achieved and thus it enables the use of stabilized compost as a nutrient source in agriculture (Doublet et al 2011). Addition of materials to improve free air space (FAS) of the initial mixture may bring about composting process to the optimum levels in terms of moisture content, C/N ratio, particle size, and pH while also ensuring a high rate of decomposition of organic matter (Ingelmo et al 2012).…”