Manure from Our Agricultural Animals: A Quantitative and Qualitative Analysis Focused on Biogas Production

Abstract

Currently, the world population is about 7.39 billion people. However, there are also billions of agricultural animals consuming resources and producing effluents that are having a negative impact on the environment. In 2014, there were about 21.3 billion chickens, 1.67 billion cattle and buffaloes, 1.21 billion sheep, 1.01 billion goats and 0.98 billion pigs. This work presents ready-to-use information on the number of agricultural animals by country, as well as their manure production rate and methane potential; based on quantitave and qualitative data obtained from the Food and Agriculture Organization (FAO), a farm located in the Slovak Republic, the Ministry of Agricultural and Rural Development of the Slovak Republic and available scientific literature. In this context, it was determined that agricultural animals can produce as much manure as 20 million tons of dry matter (TS) and 10 million tons of organic dry matter (VS) daily. Furthermore, it was estimated that there is a methane potential rate of about 1900 million Nm3 d−1 and a gross energy potential rate of 21,000 GWh d−1. Two indexes, one related to water infrastructure and sanitation development, and the other related to transport and infrastructure were introduced in order to estimate a maximum feasible methane production rate for each country. The main intention of this work is to re-open the dialogue concerning the impact that our agricultural animals have on the environment and to encourage the wider application of anaerobic digestion for the waste management of manure and biogas production.