Evaluating Environmental Parameters for Minimum Ammonium Losses during Composting of Trimming Residues

Abstract

A neural fuzzy system was used to investigate the influence of environmental variables (time, aeration, moisture, and particle size) on composting parameters (pH, organic matter [OM], nitrogen [N], ammonium nitrogen [NH 4 ϩ -N] and nitrate nitrogen [NO 3 Ϫ -N]). This was to determine the best composting conditions to ensure the maximum quality on the composts obtained with the minimum ammonium losses. A central composite experimental design was used to obtain the neural fuzzy model for each dependent variable. These models, consisting of the four independent process variables, were found to accurately describe the composting process (the differences between the experimental values and those estimated by using the equations never exceeded 5-10% of the former). Results of the modeling showed that creating a product with acceptable chemical properties (pH, NH 4 ϩ -N and NO 3 Ϫ -N) entails operating at medium moisture content (55%) and medium to high particle size (3-5 cm). Moderate to low aeration (0.2 L air/min ⅐ kg) would be the best compromise to compost this residue because of the scant statistical influence of this independent variable.

Changes in Physico-Chemical Parameters During Forced-Aeration Static-Pile Co-Composting of Cattle Manure With Calcium Cyanamide

“…However, different results have been found in some studies, for instance, Bueno et al (2009) reported that the NH 4 + -N concentrations increased significantly at the initial stage and then decreased during composting of trimming residues at different levels of moisture and particle size. 6, the NH 4 + -N concentrations in all piles, although occurring at different times, increased significantly at the initial stage and reached their maximum level because of ammonification which is always associated with temperature increase and mineralization of organic N compounds (Bueno et al 2009). 6, the NH 4 + -N concentrations in all piles, although occurring at different times, increased significantly at the initial stage and reached their maximum level because of ammonification which is always associated with temperature increase and mineralization of organic N compounds (Bueno et al 2009).…”

“…6, the NH 4 + -N concentrations in all piles, although occurring at different times, increased significantly at the initial stage and reached their maximum level because of ammonification which is always associated with temperature increase and mineralization of organic N compounds (Bueno et al 2009). During the thermophilic phase, lower increments were detected with respect to the mesophilic phase because of the inhibitory effect of NH 3 and high temperature on the growth of nitrifying bacteria (Huang et al 2004;Bueno et al 2009). Except in test III, the NH 4 + -N contents in other piles were <400 mg/kg at the end of composting, which is the maximum limit recommended for a mature compost.…”

“…As shown in Fig. Then, the NH 4 + -N concentrations decreased due to NH 3 volatilization and immobilization by microorganisms (Bueno et al 2009), indicating that the inhibitor was gradually eliminated as composting process continued. Then, the NH 4 + -N concentrations decreased due to NH 3 volatilization and immobilization by microorganisms (Bueno et al 2009), indicating that the inhibitor was gradually eliminated as composting process continued.…”

“…One of the nutrient losses during composting is N which is mainly lost as ammonia (NH 3 ) but may also as N 2 , N 2 O and NO x (Bueno et al 2009;Velasco-Velasco et al 2011). The N losses during composting can be influenced by several factors including temperature, pH, C/N ratio, and turning (Parkinson et al 2004;Bueno et al 2009). The N losses during composting can be influenced by several factors including temperature, pH, C/N ratio, and turning (Parkinson et al 2004;Bueno et al 2009).…”