Efficiency of batch model biodigestors in the treatment of swine manure in deep litter

Abstract

Swine production is characterized as a potentially harmful activity to the environment. Therefore, it is necessary to find alternatives that can minimize problems caused by this activity. Among the alternatives, we highlight the use of deep litter, which provides a breeding system that promotes the treatment of waste in solid form. The digester is used as an adjunctive treatment to the deep litter as this alone is not sufficient to remove all content of polluting waste. The objective of study was to evaluate the efficiency of laboratory digesters in reducing pollutant loads from swine deep litter. Deep litter composed of wood shavings and sugarcane bagasse was used. Samples were collected at the inlet and outlet of the biodigester. Six model laboratory batch digesters with a volume of 20 liters were used in treatment. For the efficiency reduction pollutants manure analysis, the following physical-chemical parameters were analyzed in the inlet and outlet: Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Solids (TS), total nitrogen, total phosphorus and pH. The mean removal efficiencies of BOD, COD, TS were 53.38; 54.53% and 44.97%, respectively. Based on the results it was found that the anaerobic treatment system was effective to reduce and stabilize the organic matter of the manure. There was an increase in total nitrogen and total phosphorus after treatment, which makes its favorable for use as a biofertilizer. There were no significant changes in pH indicating good tamponade of the system.