HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Figures Only Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (10) Citing Articles via Google Scholar Google Scholar Articles by Nakasaki, K. Articles by Ohtaki, A. Search for Related Content PubMed PubMed Citation Articles by Nakasaki, K. Articles by Ohtaki, A. Agricola Articles by Nakasaki, K. Articles by Ohtaki, A. Related Collections Other Models Municipal Waste Other Waste Management

TECHNICAL REPORTS
Waste Management

A Simple Numerical Model for Predicting Organic Matter Decomposition in a Fed-Batch Composting Operation

Department of Materials Science and Chemical Engineering, Shizuoka Univ., 3-5-1 Johoku, Hamamatsu, 432-8561, Japan

* Corresponding author (tcknaka{at}ipc.shizuoka.ac.jp)

Received for publication June 4, 2001.

	ABSTRACT

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Using dog food as a model of the organic waste that comprises composting raw material, the degradation pattern of organic materials was examined by continuously measuring the quantity of CO₂ evolved during the composting process in both batch and fed-batch operations. A simple numerical model was made on the basis of three suppositions for describing the organic matter decomposition in the batch operation. First, a certain quantity of carbon in the dog food was assumed to be recalcitrant to degradation in the composting reactor within the retention time allowed. Second, it was assumed that the decomposition rate of carbon is proportional to the quantity of easily degradable carbon, that is, the carbon recalcitrant to degradation was subtracted from the total carbon remaining in the dog food. Third, a certain lag time is assumed to occur before the start of active decomposition of organic matter in the dog food; this lag corresponds to the time required for microorganisms to proliferate and become active. It was then ascertained that the decomposition pattern for the organic matter in the dog food during the fed-batch operation could be predicted by the numerical model with the parameters obtained from the batch operation. This numerical model was modified so that the change in dry weight of composting materials could be obtained. The modified model was found suitable for describing the organic matter decomposition pattern in an actual fed-batch composting operation of the garbage obtained from a restaurant, approximately 10 kg d^-1 loading for 60 d.

	INTRODUCTION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
COMPOSTING OF MUNICIPAL refuse has gained attention because municipal refuse contains large quantities of organic fractions, such as garbage, which can be reclaimed to farmland. In Japan, however, the composting of municipal refuse is not widespread, and at present no more than 30 composting plants operate nationwide. This is because farmers cannot use compost that contains large quantities of impurities, such as plastics. It is expensive to separate such unsuitable materials from municipal refuse, which contains garbage from many sources, and it is difficult to avoid contamination by heavy metals and plastics even when a high-quality separator is used. It is therefore necessary to sort garbage for composting at the place where it is generated. A large number of medium-scale and small-scale composting machines, which allow organic waste to be treated at the generating site, have been developed in Japan in recent years (Shoda, 1996).

The so-called fed-batch system is used in both medium-sized composting machines, which compost meal residues at restaurants and hospitals, and small-scale composting machines, which handle household kitchen waste. In the fed-batch system, raw materials are added daily to the composting machine, and the accumulated materials are agitated and mixed. The compost product is not discharged from the machine until several months have passed. Biochemical engineers have done a great deal of research into fed-batch cultures. Their results have been summarized in several texts (e.g., Crueger and Crueger, 1984; Bushell, 1988). Although biochemical engineers study fed-batch operation from the standpoint of enhancing the efficiency of producing the fermentation product, it should be noted that the fed-batch system has been selected for use in composting not because of its productivity, but because the raw material is generated intermittently.

Several reports have been made on the degradation of organic materials in fed-batch composting operations (Liu et al., 1992; Liu and Mori, 1993; Nakasaki et al., 1998, 2000). In our previous research, fed-batch operation was conducted by daily adding an equal amount of the same previously prepared raw material, and the differences in the degradation patterns of organic raw material between batch and fed-batch operations were discussed (Nakasaki et al., 1998). After that, we predicted the degradation pattern of organic material in fed-batch operation on the basis of the degradation pattern of organic material in batch operation (Nakasaki et al., 2000). However, in that prediction, we used the time course of the degradation pattern of organic material in batch operation directly in order to calculate the pattern in fed-batch operation, instead of describing the pattern as a simple equation of a time-dependent function. That is, the raw material that was added every day in the fed-batch operation independently degraded in a pattern similar to that of the organic material in the batch operation. In the present study, we tried to form a simple equation to describe the degradation pattern of organic material in batch operation, and then, with that simple equation serving as the basis for a numerical model, we tried to predict the degradation pattern of organic material in a fed-batch operation.

Many researches so far have used composting kinetics and constructed numerical models, and the validity of these models has been ascertained in the various composting systems (Haug, 1993; Rosso et al., 1993; Stombaugh and Nokes, 1996; Richard and Walker, 1999; Shin et al., 1999; Agamuthu et al., 2000; Huang et al., 2000; Lasardi et al., 2000). To our knowledge, however, no previous reports have attempted to predict the decomposition of organic matter in fed-batch composting. This may be because fed-batch composting is not popular except in Japan and some other countries. It would be helpful, in attempting to design a high-performance fed-batch composting machine, to have a way to apply data from a short-term batch experiment in order to predict organic matter degradation during long-term fed-batch operation. Therefore, a simple numerical model that can predict organic matter degradation of a fed-batch operation has been urgently required.

	MATERIALS AND METHODS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Raw Materials for Composting
A commercial dog food with the trade name VITA-ONE Soft (Japan Pet Food Co. Ltd., Tokyo) was used as a model for the organic waste that comprises composting raw materials (Nakasaki et al., 1998). In preliminary experiments, the use of dog food as a model of organic waste was shown to give good reproducible data on composting, provided that the dog food's composition was uniform. The carbon and nitrogen contents, on a dry weight basis as determined by elemental analysis (three replicates), were 38.2% (±SD = 0.3%) and 4.2% (±SD = 0.2%), respectively. Thus, the carbon to nitrogen ratio was approximately 9.1 to 1. The ash content of the dog food, as determined from ignition loss at 550°C (three replicates), was 9.7 (±SD = 0.2%), and the percentages of organic matter constituents, as supplied by the maker of the dog food, were as follows: proteins >29.5%, fats >9.6%, dietary fibers <4.7%, and the remainder (including carbohydrates) approximately 47.9% on a dry weight basis. The dog food was minced before being used as a composting material.

Composting Operation
A schematic diagram of the composting apparatus is shown in Fig. 1 . The stainless steel composting reactor was cylindrical (160 mm in diameter, 180 mm in depth) with a perforated plate at the bottom to distribute the air supply (Nakasaki et al., 1998). A batch operation experiment (Run A) and a fed-batch operation experiment (Run B) were conducted. In Run A, 100 g of sawdust (in dry weight) was used as a bulking agent, and 1.12 g of inoculum (in dry weight), which was a commercially available seeding material (Alles G; Matsumoto Laboratory of Microorganisms, Ltd., Matsumoto, Japan), was used as a starter culture. The sawdust and the inoculum were mixed thoroughly and placed inside the reactor. At the start of the composting process, 112 g of dog food (dry weight), which served as the raw compost material, was introduced into the reactor. Thus, the mixing ratio of sawdust, inoculum, and dog food was 90:1:100 on a dry weight basis. In Run B, however, 1.12 g of dog food was added daily to the reactor after the sawdust and the inoculum had already been placed there and mixed. At the start of both experiments, the pH was adjusted to approximately 8.5, and the moisture content was adjusted to approximately 55% after the dog food was initially introduced. The reactor was submerged in a water bath (0.55 by 0.55 by 0.4 m³) to control the reaction temperature. The temperature was raised from room temperature to the set point of 60°C at a constant rate, and that temperature was maintained until the end of the experiment.

View larger version (43K): [in this window] [in a new window]   Fig. 1. Schematic diagram of the experimental composting system.

The compost was manually turned in the reactor every 24 h in order to ensure uniform decomposition. Throughout the composting process, a sample was withdrawn each time the compost was turned, its moisture content was measured, and then an adequate amount of distilled water was added to the remaining compost to prevent it from drying out and to maintain the moisture content in the optimum range of 40 to 60% (Nakasaki et al., 1994). Runs A and B were terminated at 6 and 14 d after the start of the composting experiments, respectively. The reproducibility of the experimental results for Runs A and B was checked by performing triplicate runs.

A Simple Numerical Model for the Batch Operation
An attempt to evaluate the quantity of organic matter decomposition in the dog food in Run A was made by constructing a simple numerical model. Three assumptions were made in calculating the percentage of carbon loss, as follows. First, a certain quantity of carbon in the dog food was assumed to be recalcitrant to degradation in the composting reactor within the retention time allowed. Second, the decomposition rate of carbon was assumed to be proportional to the quantity of easily decomposable carbon remaining in the dog food. Third, a certain lag was assumed to occur before the beginning of active decomposition of the organic matter in the dog food. This lag corresponds to the time required for microorganisms to proliferate and become active. Under these assumptions, the rate of organic matter decomposition, that is, the consumption rate of carbon corresponding to the production of CO₂, is shown by the following equations:

[1]

[2]

where C is the carbon quantity of the organic materials in the dog food (kg), C_r is the carbon quantity recalcitrant to degradation in the dog food (kg), t_L is the lag time before the organic material begins to decompose (h), and is the degradability coefficient based on the quantity of carbon in the dog food (h^-1). By integrating Eq. [2], the following equation is obtained:

[3]

where C₀ is the initial carbon quantity of organic materials in the dog food (kg). Therefore, the percentage of carbon loss, X_C, is expressed by using a fraction to stand for the carbon recalcitrant to degradation in the dog food, f_r (= C_r/C₀) as follows.

[4]

[5]

Application of the Numerical Model for Predicting the Fed-Batch Operation
The degradation pattern of the organic material during the fed-batch operation was predicted, as follows, from the numerical model constructed in the batch operation. First, in the fed-batch operation, it was assumed that the dog food that was added every day independently degraded in a pattern similar to that of the organic material in the batch operation. Secondly, it was assumed that the fed-batch operation required a shorter time lag to achieve a high-density level of microorganisms than the batch operation did, because in the fed-batch system the dog food is put into the reactor when microorganisms are already proliferating. For the sake of simplicity in calculation, the lag time, t_L, was always kept at zero, even for the dog food placed in the reactor at the start of the fed-batch operation (i.e., on the 0th day). The carbon quantity of the dog food introduced on the ith day of operation is expressed as follows:

[6]

By taking into account the carbon quantity of each batch of dog food that had been added by a certain time in the fed-batch operation, and by summing these carbon quantities, we obtained the total quantity of carbon remaining inside the reactor at the time of measurement. To calculate carbon loss as a percentage, we subtracted this quantity from the cumulative carbon quantity of the dog food introduced into the reactor up to that time, and divided the difference by the cumulative carbon quantity introduced into the reactor up to the time of measurement. The time course of carbon loss in the fed-batch operation was predicted by sequentially repeating this calculation. Thus, the percentage of carbon loss for the fed-batch operation with the daily addition of an equal amount of the same previously prepared raw material at the operation time t, between the Nth and (N + 1)th days, is expressed as:

[7]

Fed-Batch Operation of Composting Machine Treating Actual Garbage from a Restaurant
Using a medium-sized (500-L volume capacity) composting machine, actual garbage discharged from a restaurant was composted. The garbage was a mixture of many kinds of organic constituents, including fruit and vegetable trimmings, fish and meat cooking residues, and leftovers including those cooked materials. However, the garbage did not include paper or cardboard. Before the fed-batch operation began, we placed into the machine a mixture of sawdust as a bulking agent and a commercially available seeding material, Alles G, as an inoculum; the mixing ratio was 90:1 on a dry weight basis (64.8 kg wet weight, with 48% moisture content). It is well known that, in the early stages of composting, garbage tends to show a decrease in pH associated with the production of organic acids. In raw materials with an initially low pH, microbial activities are inhibited by the temporary drop in pH, and thus the decomposition of organic materials in the composting may come to a stop. Therefore, we adjusted the pH of the raw mixture to around 8.5 by adding 0.2 kg of slaked lime. This was done to maintain a weakly alkaline condition despite the drop in pH at the early stages of composting.

This machine was continuously operated for 60 d by introducing an average of 10 kg wet weight of garbage per day. The temperature of the composting material was kept at around 60°C, both by self-heating and by the regulation of supplied air temperature. The aeration rate was adjusted to 400 L min^-1, and the compost was turned intermittently (i.e., once per hour, for three minutes). Although the concentration of CO₂ cannot be monitored in this fed-batch operation, the total weight, including the machine itself and the composting material, was measured continuously because the machine was kept on a loading gauge. A sample of the composting material was removed from the composting machine each time the compost was turned (which was before the daily garbage was added), and was then subjected to moisture content analysis. Afterward, an adequate amount of tap water was added to prevent the compost from drying out.

The percentages of reduction and decomposition of the garbage were calculated during the fed-batch operation of composting. The percentage of reduction was defined as the ratio of weight loss (from organic matter decomposition and water vaporization) to the cumulative wet weight of garbage introduced into the composting machine. The weight loss was calculated by subtracting the residual wet weight of the composting materials, excluding the sawdust and the inoculum, from the cumulative wet weight of garbage introduced into the machine. The percentage of decomposition was defined as the ratio of the dry weight decrease associated with organic matter decomposition to the cumulative dry weight of garbage introduced into the machine. It can be deduced from the results of the fed-batch composting of dog food in the present research (as discussed below) that the CO₂ evolved from sawdust and inoculum will be negligible also in fed-batch composting of actual garbage from restaurants. Thus, we did not account for the weight loss of the sawdust and inoculum in calculating the percentages of reduction and decomposition. Because the moisture content of garbage introduced into the machine was not measured every day, the percentage of decomposition of garbage cannot be determined accurately. However, for calculating the percentage of decomposition, a value of 80.7%, which was the averaged value for the six intermittent measurements of moisture content for garbage (±SD = 3.8%) during the composting, was used as the moisture content for all the garbage introduced daily.

	RESULTS AND DISCUSSION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Comparison of the Degradation Pattern of Organic Material in the Batch and Fed-Batch Operations
Changes in the percentages of carbon loss for Runs A and B are compared in Fig. 2 . The averaged carbon loss in the batch operation began to rise at the composting time of 10 h, then increased rapidly, and finally leveled off near 93.8%. The final value of carbon loss did not exceed 100%, unlike in the batch composting in our previous research (Nakasaki et al., 2000), in which carbon loss reached 120% in the final stages of composting. That high value of carbon loss attained in our previous research was explained by the fact that the mixing ratio of sawdust to dog food was relatively high (90:10). In the previous research, the CO₂ evolution from sawdust was estimated by mixing a known quantity of protein hydrolysate (peptone) with the sawdust and then subtracting the CO₂ that originated from the peptone from the overall CO₂ evolution from the sawdust–peptone mixture. It was clarified that the CO₂ evolution from the sawdust was far smaller than that from the same dry weight of the dog food; that is, the ratio of the CO₂ evolved from the sawdust to that from the dog food was approximately 1:30 (Nakasaki et al., 2000); however, the CO₂ evolution from the sawdust could not be ignored in case the mixing ratio of sawdust to dog food was high as in the previous research. By contrast, in Run A where the mixing ratio of sawdust and dog food was set at 90:100, it can be assumed that the quantity of CO₂ evolved from sawdust was negligible relative to that from dog food. In addition, the mixing ratio of inoculum to the dog food in Run A was 1:100, which was quite small. Thus, the contribution of CO₂ evolved from inoculum can be considered negligible in relation to the total CO₂ evolution in Run A. The percentage of carbon loss in the previous research, obtained after correction for sawdust degradation, corresponded to the percentage of carbon loss from the dog food alone, which was proven to be 89.7% (Nakasaki et al., 2000). The difference in carbon loss between the previous and the present studies was small. This suggested that the assumption of ignoring the CO₂ evolution associated with sawdust and inoculum in Run A was practically acceptable.

View larger version (20K): [in this window] [in a new window]   Fig. 2. Changes in the percentage of carbon loss, XC, with time during composting. Error bars indicate ±SD. (A) Batch operation. (B) Fed-batch operation.

Description of the Carbon Loss in the Batch Operation by the Numerical Model
Table 1 shows three sets of three parameters, denoted as Sets I, II, and III, used for calculating Eq. [5]. A set of parameters, t_L = 18 h, = 0.033 h^-1, and f_r = 0.060, shown as Set II in the table, was determined by Marquardt's method, which is popularly used to estimate the parameters of a nonlinear equation in order to fit the calculated results and the experimental data. The other sets of parameters (i.e., Sets I and III) were used to show the sensitivity of the calculated results on the set of parameters. Figure 3 compares the measured data of the percentage of carbon loss in Run A and the calculated results using the numerical model with the three sets of parameters. If the Set II parameters are adopted, the calculated and measured values coincide with each other (R² = 0.99) after the first day of composting, which includes the time required for the microorganisms to proliferate and become active. The t_L, , and f_r values affect the standing-up point, the slope gradient, and the final approaching value of the carbon loss curve, respectively. The larger the value, the steeper the slope became; and the smaller the f_r value, the higher the final approaching value of the curve became. The physical meaning of was clear, but the reason why the single value of can express the organic matter decomposition rate of dog food—a mixture of many different kinds of organic constituents (proteins, carbohydrates, fats, and dietary fibers) with various degrees of degradability—remains unexplained.

View larger version (20K): [in this window] [in a new window]   Fig. 3. The courses over time of the measured and calculated values of percentage of carbon loss during the composting of the batch operation. Calculated values were obtained using Eq. [5] with each of the three sets (I–III) of parameters shown in Table 1.

View larger version (29K): [in this window] [in a new window]   Fig. 4. The courses over time of the measured and predicted values of percentage of carbon loss during the composting of the fed-batch operation. Predicted values were obtained using Eq. [7] with the three sets of parameters (I–III) shown in Table 1. For the sake of simplicity in calculation, tL was always kept at zero, even for the dog food thrown into the reactor at the start of the fed-batch operation on the 0th day.

View larger version (25K): [in this window] [in a new window]   Fig. 5. The courses over time of the cumulative wet weight of garbage introduced into the composting machine, and the residual wet weight of the garbage.

View larger version (21K): [in this window] [in a new window]   Fig. 6. The courses over time of the moisture content, and the percentage of reduction calculated as a ratio of weight loss (from organic matter decomposition and water vaporization) to the cumulative wet weight of the garbage introduced into the composting machine.

[8]

where Dⁱ₀ is the dry weight of the garbage introduced into the machine (kg), Dⁱ_r is the dry weight of organic matter recalcitrant to degradation and ash in the garbage (kg), and ß is the degradability coefficient determined on the basis of the dry weight of the garbage (h^-1). By assuming constant values (throughout the composting) for the fraction of dry weight recalcitrant to degradation, including the ash in the garbage, g_r , and ß, then the percentage of decomposition of garbage, X_D, is expressed as follows:

[9]

Figure 7 compares the percentage of decomposition, predicted by using the simple numerical model with a constant value of ß, 0.025 h^-1, and three different values of g_r (0.31, 0.38, and 0.45), with the measured percentages of decomposition. Though not shown here, the influence of the value of ß on the predicted results was restricted only at the earliest stage of composting (i.e., the slope gradient of the rise in the decomposition curve). The rise in the decomposition curve was explained by the value of ß, 0.025 h^-1, which is smaller than that obtained for the dog food, . This indicates the garbage was less degradable than the dog food. Weight loss associated with organic matter degradation in the batch operation was described by a first-order kinetic equation, and the first-order kinetic constant, which corresponds to the degradability coefficient based on the dry weight of garbage in the present research (ß), was in the range of 1.7 x 10^-4 to 0.027 h^-1 (Haug, 1993; Shin et al., 1999). It was difficult to compare the kinetic constant from this research to those of previous researchers, because the conditions of composting—such as the kinds of organic wastes, C to N ratio, temperature, moisture content, and pH—differed in each experiment.

View larger version (28K): [in this window] [in a new window]   Fig. 7. The courses over time of the measured and predicted values of the percentage of garbage decomposition using three different values for gr, a fraction of dry matter recalcitrant to degradation in the garbage. Closed circles are for the measured values, and the solid, broken, and dotted lines refer to the predicted values by using Eq. [9] with the gr values of 0.31, 0.38, and 0.45, respectively.

	CONCLUSIONS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Using dog food as a model of the organic waste that comprises composting raw material, the degradation pattern of organic materials was examined by continuously measuring the quantities of CO₂ that evolved during the composting process in both batch and fed-batch operations. A simple numerical model was made to describe the organic matter degradation in the batch operation, and this model was then used to predict organic matter degradation in the fed-batch operation. The degradation pattern of the organic material during the fed-batch operation was successfully predicted by the numerical model and by the parameters determined from the batch operation. Moreover, it was possible to predict the degradation pattern of organic material in an actual fed-batch operation, in which garbage from a restaurant was put into a composting machine at the rate of 10 kg d^-1 for 60 d.

The sensitivity of the numerical model for predicting the decomposition rate must be examined by varying the quality and quantity of the composting raw material added daily to composting machines, and by varying the operational conditions of composting. This will further our understanding of the actual fed-batch operation of composting machines.

	ACKNOWLEDGMENTS

 
This research was supported partly by a Grant-in-Aid from the Scientific and Technology Agency of Japan.

	REFERENCES

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 

• Agamuthu, P., L.C. Choong, S. Hasan, and V.V. Praven. 2000. Kinetic evaluation of composting of agricultural wastes. Environ. Technol. 21:185–192.
• Bushell, M.E. 1988. Progress in industrial microbiology. Volume 25. Computers in fermentation technology. Elsevier Sci. Publ., Amsterdam.
• Crueger, W., and A. Crueger. 1984. Biotechnology a textbook of industrial microbiology. Sinauer Associates, Sunderland, MA.
• Haug, R.T. 1993. The practical handbook of compost engineering. Lewis Publ., Boca Raton, FL.
• Huang, J.-S., C.-H. Wang, and C.-G. Jih. 2000. Empirical model and kinetic behavior of thermophilic composting of vegetable waste. J. Environ. Eng. 126:1019–1025.
• Lasardi, K.E., E.I. Stentiford, and T. Evans. 2000. Windrow composting of wastewater biosolids: Process performance and product stability assessment. Water Sci. Technol. 42:217–226.
• Liu, B.G., and T. Mori. 1993. Complete treatment of shochu processed wastewater by thermophilic oxic process. Proc. Environ. Eng. Res. 30:165–174.
• Liu, B.G., S. Noda, and T. Mori. 1992. Complete decomposition of organic matter in high BOD wastewater by thermophilic oxic process. Proc. Environ. Eng. Res. 29:77–84.
• Nakasaki, K., N. Akakura, K. Atsumi, and M. Takemoto. 1998. Degradation patterns of organic material in batch and fed-batch composting operations. Waste Manage. Res. 16:484–489.[Abstract/Free Full Text]
• Nakasaki, K., N. Akakura, and M. Takemoto. 2000. A Prediction for the degradation pattern of organic materials in the composting of a fed-batch operation as inferred from the results of a batch operation. J. Material Cycles Waste Manage. 2:31–37.
• Nakasaki, K., N. Aoki, and H. Kubota. 1994. Accelerated composting of grass clippings by controlling moisture level. Waste Manage. Res. 12:13–20.
• Nakasaki, K., A. Watanabe, M. Kitano, and H. Kubota. 1992. Effect of seeding on thermophilic composting of tofu refuse. J. Environ. Qual. 21:715–719.[Abstract/Free Full Text]
• Richard, T.L., and L.P. Walker. 1999. Oxygen and temperature kinetics of aerobic solid-state biodegradation. p. 85–91. In W. Bidlingmaier et al. (ed.) Proc. of Organic Recovery and Biological Treatment, Part 1, ORBIT99, Weimar, Germany. 2–4 Sept. 1999. Rhombos Verlag, Berlin.
• Rosso, L., J.R. Lobry, and J.P. Flandrois. 1993. An unexpected correlation between cardinal temperatures of microbial growth highlighted by a new model. J. Theor. Biol. 162:447–463.[Web of Science][Medline]
• Shin, H.-S., E.-J. Huang, B.-S. Park, and T. Sakai. 1999. The effects of seed inoculation on the rate of garbage composting. Environ. Technol. 20:293–300.
• Shoda, M. 1996. The present situation and a new trend on composting in Japan. p. 722–728. In M. de Beltoldi et al. (ed.) The science of composting. Blackie A&P, London.
• Stombaugh, D.P., and S.E. Nokes. 1996. Development of a biologically based aerobic composting simulation model. Trans. ASAE 39:239–250.

This article has been cited by other articles:

				J. I. Chang, J. J. Tsai, and K. H. Wu Composting of vegetable waste Waste Management Research, August 1, 2006; 24(4): 354 - 362. [Abstract] [PDF]

				K. Nakasaki, K. Nagasaki, and O. Ariga Degradation of Fats during Thermophilic Composting of Organic Waste Waste Management Research, August 1, 2004; 22(4): 276 - 282. [Abstract] [PDF]

This Article Abstract Figures Only Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (10) Citing Articles via Google Scholar Google Scholar Articles by Nakasaki, K. Articles by Ohtaki, A. Search for Related Content PubMed PubMed Citation Articles by Nakasaki, K. Articles by Ohtaki, A. Agricola Articles by Nakasaki, K. Articles by Ohtaki, A. Related Collections Other Models Municipal Waste Other Waste Management