METHANE FERMENTATION OF DUNG FROM LITTER-FREE REARED DOMESTIC-ANIMALS- AN OPTIMIZATION STUDY

Data on the quantity (27 453 tons from litter-free reared animals in B ulgaria, only) and the chemical and energy characteristics of dung pro duced in intensive management farms for domestic animals suggests that technologies combining biogenic elements recycling with energy utilis ation and dung decontamination are expedient to be applied on these ty pes of farms. To this effect a fermenter was designed and a mathematic al model (a Chen-Hashimoto model based computer programme) was applied , as a result of which the optimum methane fermentation parameters wer e determined. The technological methane output (Y-v) - indicator of bi ogas production efficiency (output/dm(3) fermenter volume) showed an o ptimum at temperature 55 degrees C and period of exchange 6 days. The methane output per unit mineralised organic matter in the substrate (B ) - assumed as an indicator of ecological efficiency (maximum organic matter degradation) exhibited an optimum at 33 degrees C for 15 days p eriod of exchange.