Anaerobic co-digestion of hatchery waste and wastewater to produce energy and biofertilizer - Batch phase

ABSTRACT Aiming to evaluate different wastewaters in the anaerobic co-digestion (ACoD) of hatchery wastes, a batch test was conducted in bench horizontal digesters. At the end of the process, the potential production of biogas and methane was calculated as well as the chemical composition (macro- and micronutrients) of the effluent and the concentrations of methane and carbon dioxide gas at 60 days. The monitoring of the process included observations of the reduction of the organic carbon, chemical oxygen demand, and total (TS) and volatile solids (VS), as well as the variation of pH and electrical conductivity (EC). The results showed that the mixing between the hatchery fresh waste and swine wastewater (T4) and among fresh hatchery waste, water from the first anaerobic pond of the hatchery and swine wastewater (T5) represent significant sources of renewable energy and thereby greater potential for biogas production (192.50 and 205.0 L biogas per kg of VS added to T4 and T5, respectively). The average concentration of methane in the biogas varied from 72 to 77% among the treatments. For all treatments, reductions were observed in TS and VS and increases in pH and EC. It was concluded that the energy recovery from hatchery wastes is favoured by the addition of swine wastewater in the ACoD process.