Biogas production from ruminant and monogastric animal manure co-digested with manipueira

The aim of this study was to evaluate ruminant and monogastric animal manure co-digested with 10 % of manipueira through process monitoring parameters and biogas production. In this study, eight semi-continuous digesters, with a capacity of 7.8 liters of substrate in fermentation, operated with 30 days of hydraulic retention time, were used. Monitoring analyses were performed in order to assess: pH, total ammonia nitrogen (TAN) concentration, partial alkalinity (PA), content and biogas yield (m3·kg·Volatile Solids (VS)added). There was no statistic difference for all the pH values, which reached values around 6.8 to 8.0. For PA, all the substrates reached higher than 1.200 mg·L-1 values as recommended. During the process, there was no risk of failure due to TAN concentration. The average biogas productions accumulated per week were 0.00676; 0.01167; 0.01515 and 0.01856 m3 for substrates composed by dairy cattle, sheep, poultry and swine manure co-digested with manipueira, respectively. The biogas yield for those respective substrates were 0.122; 0.275; 0.535 e 0.843 m·kg·VSadded. The highest biogas yield was obtained for anaerobic co-digestion of swine manure with 10 % (volume/ volume) of manipueira.