Article

Thermophilic anaerobic co-digestion of cattle manure with agro-wastes and energy crops: Comparison of pilot and full scale experiences

Department of Environmental Sciences, University Ca' Foscari of Venice, Dorsoduro 2137, I-30123 Venice, Italy.
Bioresource Technology (Impact Factor: 4.49). 09/2009; 101(2):545-50. DOI: 10.1016/j.biortech.2009.08.043
Source: PubMed

ABSTRACT

The paper deals with the benefits coming from the application of a proper process temperature (55 degrees C) instead of a 'reduced' thermophilic range (47 degrees C), that is often applied in European anaerobic co-digestion plants. The experimental work has pointed out that biogas production improve from 0.45 to 0.62 m(3)/kg VS operating at proper thermophilic conditions. Moreover, also methane content was higher: from 52% to 61%. A general improvement in digester behaviour was clear also considering the stability parameters comparison (pH, ammonia, VFA content). The second part of the study takes into account the economic aspects related to the capital cost of anaerobic digestion treatment with a 1 MW co-generation unit fro heat and power production (CHP). Moreover, the economic balance was also carried out considering the anaerobic supernatants treatment for nitrogen removal. The simulation showed how a pay-back-time of 2.5 yr and between 3 and 5 yr respectively could be determined when the two options of anaerobic digestion only and together with the application of a nitrogen removal process were considered.

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    • "Fifty percent of the average digester diet is represented by liquid manure, whereas shares of 25%, 20% and 5% are a result of the use of (i) corn silage, (ii) industrial by-products (i.e., glycerine and vegetable oils) and organic urban waste and (iii) winter cereal silage, respectively [9]. Ninety-six percent of the total regional plants are characterized by a nominal power class up to 0.999 MW, corresponding to the maximum threshold for obtaining public funding for electricity production from renewable sources [24]. Given the strict European regulations for nitrogen loads, biogas plants also represent a solution for limiting the negative externalities from disposal of livestock manures, such as groundwater nitrate pollution [25]. "
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