The Respiration Rate of Composting Pig Manure

Composting kinetics in full-scale mechanical–biological treatment plants

“…Lastly, it should be mentioned that the composting process is normally modelled using a one-time scale exponential model, but, in some situations, a two-time scale exponential model has proven to perform better (Cronjé et al, 2004;de Guardia et al, 2008;Haug, 1993;Kim et al, 2000;Komilis, 2006;Mason, 2008aMason, , 2009Ndegwa et al, 2000;Tosun et al, 2008;Zavala et al, 2004a,b). In a two-time scale model, the substrate is considered to be composed of two fractions: a fast fraction, which is degraded at a fast rate, and which dominates the kinetics in the early stages of the composting process; and a slow fraction, which is consumed at a slower rate, and which governs the kinetics in the late process stages.…”

“…The dependence of composting rate on oxygen concentration in the free air space has been commonly modelled by a Monod type equation (Bertoni et al, 1997;Bongochgetsakul and Ishida, 2008;Cronjé et al, 2004;Haug, 1993;Kim et al, 2000;Li et al, 2002;Petric and Selimbasic, 2008;Qin et al, 2007;Stombaugh and Nokes, 1996;Tollner et al, 1998;Xi et al, 2005Xi et al, , 2008Yu et al, 2009). Richard (1997), Richard and Walker (1999) and carried out detailed experimental work that analyzed the dependence of reaction rate on oxygen.…”

Optimum moisture levels for biodegradation of mortality composting envelope materials

“…Previously reported optimum moisture contents for composting range from 25% to 80% on a wet basis (w.b. ), with generally recommended values in the 50% to 70% range (Bishop and Godfrey, 1983;Haug, 1993;Imbeah, 1997;Richard et al, 2002;Cronjé et al, 2004). As is evident from this relatively wide range of reported values, there is no universally applicable optimum moisture content for composting materials.…”

“…The respiration rate of each envelope material was estimated as a function of moisture content. Microbial respiration rate (oxygen uptake and CO 2 evolution), a widely accepted indicator of the decomposition rate of organic materials (Hamelers and Richard, 2001;Richard et al, 2002;Cronjé et al, 2004), was used to identify the optimal moisture level. Respiration rate is a function of the biodegradable material mass, its stability, and environmental conditions such as temperature, moisture content, matrix bulk density, and air-filled porosity (Haug, 1993;Ekinci et al, 2002;Richard et al, 2002;Cronjé et al, 2004).…”

Application of a modified OxiTop® respirometer for laboratory composting studies

“…For composting studies it is recommended to measure the oxygen uptake rate as carbon dioxide can be produced both in aerobic and anaerobic conditions (Gómez et al 2004, Jędrczak 2007, Villaseñor et al 2011. The respiration rate based on oxygen consumption depends on several factors such as: mass of a material sample and its biodegradability and stability, temperature, moisture content, bulk density and air-fi lled porosity, time and conditions of preincubation and incubation (Haug 1993, Gómez et al 2004, Richard et al 2002, Cronjé et al 2004, Malińska and Richard 2006, Ahn et al 2008. Oxygen consumption and carbon dioxide production can be determined by respirometry including dynamic and static methods for both solid and liquid samples (Haug 1993, Jędrczak 2007.…”