Methane yields, thermophilic

Thermophilic (55 C) digestion of the caustic-treated feed at 0.4 lb VS/ft -day loading and a 6-day detention time showed the same methane yield of about 4 SCF/lb VS added as observed during mesophilic digestion of the pretreated feed at a 0.1 lb VS/ft -day loading and a 12-day detention time (Run 5T/24, Table II). However, the thermophilic gas production rate was 4-5 times the mesophilic rate. Also, the caustic requirement for feed pretreatment was lower for the thermophilic run owing to the recycling of the spent caustic solution. 

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