By quasi-continuous, three-stage mesophilic-thermophilic-mesophilic anaerobic treatment, a methane yield of 0.24 m³ per kg organic dry matter was achieved from the liquid manure of dairy cattle receiving a high-fiber diet. Given a minimum guaranteed retention time of 4 h at 55°C, the number of fecal coliforms was reduced to below 10 MPN per g fresh matter on average. The number of infectious Cryptosporidium oocysts was reduced by more than 5 log units. Increasing the feeding interval from 1 h to 4 h had no significant influence. Lowering the temperature in the first stage from 38°C to 20-25°C improved process stability in the thermophilic stage, but did not affect digestion and sanitation performance.
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By quasi-continuous, three-stage mesophilic-thermophilic-mesophilic anaerobic treatment, a methane yield of 0.24 m³ per kg organic dry matter was achieved from the liquid manure of dairy cattle receiving a high-fiber diet. Given a minimum guaranteed retention time of 4 h at 55°C, the number of fecal coliforms was reduced to below 10 MPN per g fresh matter on average. The number of infectious Cryptosporidium oocysts was reduced by more than 5 log units. Increasing the feeding interval from 1 h to...
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