Effect of seasonal changes in quantities of biowaste on full scale anaerobic digester performance
Introduction
Anaerobic digestion of the organic fraction of municipal solid waste offers several advantages: its odours can be effectively managed and is thus well accepted by neighbouring populations, and it produces energy that can be used through methane production with subsequent thermal usage (Lastella et al., 2002). The main disadvantages are the high costs involved with building and operating anaerobic digesters. This is especially the case for thermophilic digesters due to the vulnerability of the entire anaerobic process (Kim et al., 2002). Several publications discuss process dynamics, regulation and disturbance of anaerobic digestion of organics in municipal solid waste (Gallert and Winter, 1997, Fernandez et al., 2000, Pullammanappallil et al., 2001, Sterling et al., 2001, Mechichi and Sayadi, 2005), but these topics are still poorly understood.
Investigations into the performance of anaerobic digesters are often empirical collections of several process parameters like pH, the concentrations of volatile fatty acids (e.g., propionic or butyric acid) or the concentrations of several nitrogen-fractions with special consideration of . However, we know of no single investigation which includes a further, very important factor – seasonal variability. Both quality and quantity of the gathered biowaste is strongly influenced by seasonal variability in input material and usually digestion plants do not have the ability to equalize these seasonal variations.
The aim of the present investigation was therefore to point to the seasonal changes regarding quality and quantity of biowaste and thus to the impact of this variability on the total performance of a 750,000 l anaerobic digester.
Section snippets
Digester and biowaste
A 750,000 l thermophilic plug-flow reactor located in Roppen (Austria), which follows the KOMPOGAS-dry digestion principle, was investigated. Within this plant the delivered biowaste (separately gathered organic fraction of municipal solid waste) is weighed, transferred to a bunker and mixed (Mashmaster, Komptech®) with chopped branches of trees and bushes. After the separation of metals and larger pieces, the substrate is chopped down to <40 mm. Biowaste is mixed with fresh and/or process water
Process parameters
Table 1 gives an overview of the parameters determined throughout the years 2003–2004. Sample size varied between n = 9 and n = 99 depending on the different sampling intervals and missing values. Although comparable accurate process descriptions are rare, the values in Table 1 indicate that the data are approximately within the range usually known from published literature (Sharma et al., 1999, Vorkamp, 2001, Liu et al., 2004).
The amounts of, and the ratios between, several volatile fatty acids
Conclusions
This study has shown a distinct influence of the seasonality of gathered biowaste on the efficiency of the digestion process. However, further investigations concerning qualitative aspects of the input material are urgently needed. Besides this, the causal interrelationships between abiotic parameters and the microorganisms are still a “black box” and thus a better understanding is needed. Finally, a precise characterization of the input material together with some well known process parameters
Acknowledgments
The study was supported by the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management (BMLFUW) and the counties of Tyrol and Vorarlberg (Project No. 1405).
References (20)
- et al.
Thermodynamics of H2-consuming and H2-producing metabolic reactions in diverse methanogenic environments under in situ conditions
FEMS Microbiology Ecology
(1986) - et al.
Flexible community structure correlates with table community function in methanogenic bioreactor communities perturbed by glucose
Applied and Environmental Microbiology
(2000) - et al.
Mesophilic and thermophilic anaerobic digestion of source-sorted organic wastes: effect of ammonia on glucose degradation and methane production
Applied Microbiology and Biotechnology
(1997) Anaerobic digestion of biomass for methane production: a review
Biomass and Bioenergy
(1997)- et al.
Physiology and biochemistry of the methane-producing archaea
- et al.
Propionic acid accumulation and controlling factors in anaerobic treatment of carbohydrate: effects of H2 and pH
Water Science and Technology
(1996) - et al.
Propionic acid accumulation in anaerobic digestion of carbohydrates: an investigation on the role of hydrogen gas
Water Science and Technology
(1999) - et al.
Comparative process stability and efficiency of anaerobic digestion; mesophilic vs thermophilic
Water Research
(2002) - et al.
Anaerobic digestion of semi-solid organic waste: biogas production and its purification
Energy Conversion and Management
(2002) - et al.
Monitoring and control of an anaerobic upflow fixed-bed reactor for high-loading-rate operation and rejection of disturbances
Biotechnology and Bioengineering
(2004)
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