IMPROVEMENT OF ANAEROBIC CODIGESTION OF SWINE MANURE AND POULTRY MANURE BY THE ADDITION OF CATTLE MANURE

Abstract

Introduction:
In Cuba, there is a tendency to decentralize productions with the creation of livestock modules where different livestock species coexist, such as swine, cattle and poultry. In this context, anaerobic digestion (AD) is an alternative for the decarbonization of the agricultural sector, since it generates energy during waste treatment.
Objective:
To evaluate the AD of swine manure (SM) and poultry manure (PM) with cattle manure (CM) in terms of biochemical methane potential (BMP), and kinetic parameters in mono and co-digestion.
Materials and Methods:
The trial was conducted in 2 L reactors at 27 °C (average). The BMP of SM, PM and CM was determined in mono-digestion, and then with addition of 15, 30 and 45 % of CM, to the PM40:SM60 mixture. To describe the kinetic behavior of the process, experimental data were fitted to three first and second order models.
Results and Discussion:
The experimental BMP with CM addition was higher than expected, with increase between 26-31 %, demonstrating the synergy of the mixtures; since the C/N ratio and the methanogenic archaeal community were improved. The models were adjusted to the experimental data with adjusted coefficients of determination higher than 90 %.
Conclusions:
The addition of CM increased the experimental methane yield over the expected one. The Hill model shows a maximum yield of 369 LCH4/kgVS for mixtures with 15 and 30 % CM. The best variant was with 15 %, and it is necessary to transport manure from 20 cows to the biodigester.