Composting in a Laboratory Reactor: A Review

Petiot, C.; Guardia, A. de

doi:10.1080/1065657x.2004.10702160

Cited by 45 publications

(29 citation statements)

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“…Under these conditions, metabolic heat generation is combined with the thermal inertia effect found in compost materials due to their self-insulating properties (Haug, 1993), in consequence, high thermophilic temperatures are usually maintained during the maturation or stockpiling of compost (Liao et al, 1995;Avnimelech et al, 2004). This phenomenon is not observed in laboratory or pilot scale studies, in which temperature decreases rapidly when the easily biodegradable organic matter is consumed (Gea et al, 2003;Petiot and de Guardia, 2004). In general, the set-up of an industrial-scale facility is not directly transferable to laboratory-scale (Körner et al, 2003).…”

Section: Introductionmentioning

confidence: 91%

“…On the other hand, amounts of compost at laboratory scale (little mass and high area volume ratio) remain at mesophilic or ambient temperature. This phenomenon is observed in laboratory and pilot composting reactors, where the thermophilic temperature is only maintained for few weeks or even few days (Petiot and de Guardia, 2004). Afterwards, the simulated core temperature reaches a maximum value at day 15 (75ºC).…”

Section: Validation With Experimental Datamentioning

confidence: 99%

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Prediction of temperature and thermal inertia effect in the maturation stage and stockpiling of a large composting mass

2006

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A macroscopic non-steady state energy balance was developed and solved for a composting pile of source-selected organic fraction of municipal solid waste during the maturation stage (13500 kg of compost). Simulated temperature profiles correlated well with temperature experimental data (ranging from 50 to 70ºC) obtained during the maturation process for more than 50 days at full scale. Thermal inertia effect usually found in composting plants and associated to the stockpiling of large composting masses could be predicted by means of this simplified energy balance, which takes into account terms of convective, conductive and radiation heat dissipation. Heat losses in a large composting mass are not significant due to the similar temperatures found at the surroundings and at the surface of the pile (ranging from 15 to 40ºC). In contrast, thermophilic temperature in the core of the pile was maintained during the whole maturation process. Heat generation was estimated with the static respiration index, a parameter which is typically used to monitor the biological activity and stability of composting processes. In this study, the static respiration index is presented as a parameter to estimate the metabolic heat that can be generated according to the biodegradable organic matter content of a compost sample, which can be useful in predicting the temperature of the composting process.

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Section: Introductionmentioning

confidence: 91%

Section: Validation With Experimental Datamentioning

confidence: 99%

Prediction of temperature and thermal inertia effect in the maturation stage and stockpiling of a large composting mass

2006

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“…L and D In this study, the length of the reactor was varied between 0.40 m and 2.50 m and the diameter was varied from 0.20 m to 1.20 m. The proposed ranges for the length and diameter included values that have been chosen when designing and experimenting on similar compost bioreactors (Liao et al, 1994;Nakasaki et al, 1997;Darrell et al, 1998;Day et al, 1998;Freeman and Cawthon, 1999;Lehmann et al, 1999;Vining, 2002;Ekinci et al, 2004a,b;Hess et al, 2004;Hong and Park, 2004;Petiot and de Guardia, 2004;Mason and Milke, 2005;Yu et al, 2005).…”

Section: Equation Formulation and Parameter Identificationmentioning

confidence: 99%

“…The net heat loss rate determines the overall temperature of the system (Nielsen and Berthelsen, 2002). The combined conductive/convective/radiative heat loss mechanisms (Mason and Milke, 2005) can be characterized and monitored by following the variation of the overall heat-transfer coefficient (U-value) (Petiot and de Guardia, 2004) for such a system. Mathematical equations have been proposed to predict the U-values developed during the composting of a mixture of organic biodegradable wastes.…”

Section: Introductionmentioning

confidence: 99%

“…This range encompassed the thermal conductivities of a variety of plastics and insulation materials (expanded polystyrene, polystyrene, high density polythene, cotton wool, corkboard, hardboard, glass wool, fiberglass, foams (Styrofoam), polyurethane (Hogan et al, 1989;Bari et al, 2000;Adani et al, 2001;Ekinci et al, 2004b;Petiot and de Guardia, 2004;Mason and Milke, 2005;Ghaly et al, 2006) * of which the reactor could be lagged.…”

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confidence: 99%

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Sensitivity Analysis and Parameter Optimization of a Heat Loss Model for a Composting System

Mudhoo

Mohee

2006

J ENV INFORM

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ABSTRACT.A combined multi-parameter sensitivity analysis/frequency array analysis technique was employed to assess the impact of design conditions and matrix-specific properties on the rate of heat loss from a self-heating composting process. This method was specifically used to identify the range of parameters over which a model predicting the overall heat-transfer coefficients (U-values) for the heat loss process are particularly sensitive. The model was found to be most sensitive for the following range of input parameters: the internal diameter of reactor varying from 0.8 m to 1.2 m, the combined reactor wall and insulation thickness ranging from 4 cm to 6 cm, the free airspace of the matrix varying from 50% to 60%, the reactor length varying from 1.0m to 1.5m, the thermal conductivity of the organic substrates ranging from 0.1 W/m.K to 0.2 W/m.K and the preferred thermal conductivity of the insulation material being less than 0.2 W/m.K. A second sensitivity analysis was performed to identify which input parameters actually influenced the model's response the most. This analysis compared the acceptable and unacceptable frequency distributions of each input parameter, with model outputs below a U-value of 4.5 W/m 2 .K being an acceptable composting performance from a thermodynamics consideration. This analysis disclosed the matrix free airspace, the internal diameter of the reactor and the combined thickness of reactor wall and insulation as the most important parameters which should be given high priority when designing invessel compost reactors.

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A kinetic study on how C/N ratio affects energy consumption of composting of rose oil‐processing wastes with caged layer manure and straw

Onursal

Eki̇nci̇

2016

Env Prog and Sustain Energy

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Composting process parameters such as C/N ratio, moisture content, and temperature are well studied, but limited knowledge exists on energy consumption of the process itself. In this study, co‐composting of rose oil‐processing wastes (ROPW) with caged layer manure and straw was performed to optimize the system in terms of energy use. Intermittent aeration applied to the five compost mixtures with initial C/N ratios of 12.81, 21.37, 24.66, 29.22, and 37.41 was conducted using fifteen identical cylindrical reactors with volume of 60 L. O2 and CO2 concentrations, compost temperature, dry matter loss, organic matter loss, electrical conductivity, and pH were measured. A first‐order kinetic model based on material mass balance was applied to determine kinetic parameters such as decomposition rate and compost equilibrium mass. An equation describing specific energy per initial dry mass of composting as a function of initial C/N ratio was presented and used to optimize initial C/N ratio to maximize composting of ROPW to reach a given level of compost mass ratio. The maximum decomposition, based on dry matter loss, occurred at the initial C/N ratio of 30.18 was 0.032 kg kg−1 day−1. Initial C/N ratio to minimize specific energy use of ROPW composting with caged layer to reach a given level of compost ratio of 0.82 was 29.11. Composting operation can be performed at this initial C/N ratio (29.11) to minimize airflow to keep the power requirement low while still operating the system efficiently. This helps to reduce the energy required for ROPW composting with caged layer to reach a given compost mass ratio. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 129–137, 2017

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Composting in a Laboratory Reactor: A Review

Cited by 45 publications

References 44 publications

Prediction of temperature and thermal inertia effect in the maturation stage and stockpiling of a large composting mass

Prediction of temperature and thermal inertia effect in the maturation stage and stockpiling of a large composting mass

Sensitivity Analysis and Parameter Optimization of a Heat Loss Model for a Composting System

A kinetic study on how C/N ratio affects energy consumption of composting of rose oil‐processing wastes with caged layer manure and straw

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