Optimization of windrow food waste composting to inactivate pathogenic microorganisms

Çekmecelioğlu, Deniz
Graves, RE
Davitt, NH
Composting is a popular means of treating organic wastes, and properly controlled composting can destroy the pathogenic microorganisms present in wastes for a human- and environment-friendly end product. Therefore, optimization of windrow composting of food waste, manure, and bulking agents was evaluated for maximum pathogen inactivation (Salmonella and E. coli O157:H7). Seasonal effects on reductions of Salmonella and E. coli O157:H7 according to the compost temperatures were studied (90 to 150 days). Fecal coliforms and fecal streptococcus were also monitored during composting. The most probable number (MPN) method was used for enumerating both indicator and pathogenic microorganisms. The results of this study indicated that seasonal differences caused significant effects on the peak temperatures and the duration of high thermophilic temperatures (>= 55 degrees C) of windrows. Winter conditions resulted in inconsistent inactivation of pathogenic microorganisms including regrowth to high values during several time intervals. The reduction levels of Salmonella spp. and E. coli O157:H7 ranged from initial ranges of 377-483 MPN/g to final ranges of 6-150 MPN/g in whiter and to 0.90) between the number of fecal coliforms and the pathogenic microorganisms (Salmonella spp. and E. coli O157:H7). Fecal streptococcus was only slightly reduced in the majority of the trials from 377-483 MPN/g to 221-514 MPN/g in winter and from 365-460 MPN/g to a range of 11-265 MPN/g in summer Extreme Vertices Mixture Design (EVMD) analysis suggested an optimum mixture as: 43.3% food waste, 28.3% manure, and 28.3% bulking agents. The performance of the optimum mixture has been validated, achieving a high level of inactivation of pathogens similar to that with previous trials, with good correlations of fecal coliforms to the pathogens of interest, but with a high resistance of fecal streptococcus to inactivation. It was concluded that the EVMD design was successful in optimizing mixture components for windrow composting in order to achieve maximum pathogen reduction.


Applicability of optimised in-vessel food waste composting for windrow systems
Çekmecelioğlu, Deniz; Graves, RE; Davitt, NH (Elsevier BV, 2005-08-01)
The presence of pathogens in various organic wastes requires careful attention to the composting process to minimise the chance of their survival. An optimised composting mixture from previous in-vessel composting studies (50% food waste, 40% manure, and 10% bulking agent) was evaluated using windrow composting. Conventional layering and mixing methods were used for constructing the windrows. Temperature was monitored as the indication of the efficiency of composting. Initial and final physico-chemical char...
Modeling of composttemperature and inactivation of Salmonella and E-coli O157 : H7 during windrow food waste composting
Çekmecelioğlu, Deniz; Demirci, A; Graves, RE (2005-03-01)
A simulation model was developed to predict temperature and inactivation of E. coli O157:H7 and Salmonella during windrow composting. In particular, the model included an energy balance to estimate the change in temperature based on heat generated by biological decomposition and heat losses by convection, conduction, evaporation, and radiation. The model was validated with the measured data for the effects of seasonal variation on compost temperature and pathogen reduction. Sensitivity analysis was performe...
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Direct disposal of vinasse, a by-product of molasses fermentation plants, threatens environmental health. This study investigated the usage of vinasse as a nutrient source for the heterotrophic and mixotrophic cultivation of novel Micractinium sp. ME05. The 500-mL flask experiments resulted in higher biomass productivities under mixotrophic conditions (0.16 +/- 0.01 g L-1 day(1)) than the heterotrophic conditions (0.13 +/- 0.01 g L-1 day(1)). A 1.7-fold increase in biomass productivity was achieved by scali...
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Biosorption, using cadmium-resistant bacterial isolates, is often regarded as a relatively inexpensive and efficient way of cleaning up wastes, sediments, or soils polluted with cadmium. Therefore, many efforts have been devoted to the isolation of cadmium-resistant isolates for the efficient management of cadmium remediation processes. However, isolation, identification and in situ screening of efficient cadmium-resistant isolates are primary challenges. To overcome these challanges, in this study, cadA, c...
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Hydrogen can be produced sustainably by utilizing organic wastes through photofermentation. In order to obtain an economically feasible operation, the photobioreactor design is of crucial importance. An optimal photobioreactor design should provide uniform velocity and light distribution, low pressure drop, low gas permeability and efficient gas-liquid separation. The aim of this study was to design a pilot-scale photobioreactor satisfying these criteria and to test the reactor under outdoor conditions with...
Citation Formats
D. Çekmecelioğlu, R. Graves, and N. Davitt, “Optimization of windrow food waste composting to inactivate pathogenic microorganisms,” TRANSACTIONS OF THE ASAE, pp. 2023–2032, 2005, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/55900.