Two‐phase anaerobic codigestion of a cassava starch‐based biopolymer with papaya waste

Abstract

The objective of this work was to evaluate anaerobic digestion processes of mixtures of cassava starch‐based polymer (CSP) and papaya fruit pulp waste (PPW) at different ratios, with physical division of digestion stages. Acidogenic phase (phase 1) was conducted under temperature of 45°C and hydraulic retention time of 96 h. Monitoring reactors with destructive samples were subjected to the same conditions in order to assess the initial degradation profile of the substrates. The methanogenic phase (phase 2) was conducted under temperature of 37°C and the hydraulic retention time was defined as equal to the time the biogas production ceased. The results showed that the CSP/PPW mixtures presented interesting synergism and high biogas production potential under the conditions studied. The treatment with CSP/PPW at the ratio of 75/25 showed the best digestion performances in the phase 1. The highest CSP to PPW ratios showed satisfactory results for accumulated biogas productions (5955.58 mL) and for maximum biogas production rate (25.64 mL gVS−1 day−1) in the phase 2.