The Carbon Dioxide-Rumen Fermentation Processes-strategy, a proposal to sustain environmentally friendly dairy farms

Abstract

A novel Carbon Dioxide Utilization (CDU) approach from a relatively minor biogenic carbon dioxide emission source, Rumen Fermentation Processes (RFP), is presented. The CO2-RFP strategy explores the potential treatment of the liquid manure storage located at the bottom of the dairy barns with CO2-enriched air coming from cattle exhalation and belching to produce an important fertilizer such as NH4HCO3 (ABC, ammonium bicarbonate). The unusual CDU strategy, analyzed exclusively from a chemical point of view, could yield over 31.6 Million of tones, Mt, of ABC in aqueous solution using c. 18.0 Mt of CO2 and capturing c. 6.9 Mt of NH3, ammonia. This process would consume less energy than the traditional synthetic method (ABC fertilizer process) and would not produce any by-products or chemical compounds which may enter into conflict with the dairy sector. The quantity of ABC obtained by this strategy would be equivalent to four times the world production per year.Taking into consideration only the most relevant dairy countries, the estimate of the CO2negative emission achieved suggests a capture of around 1.8 Gt of CO2 equivalents and 82.8 Mt of NH3 from now to 2030. With the aim of providing a realistic outlook on the CO2-RFP strategy, the proposal is discussed considering a number of possible scenarios: the CO2-RFP strategy (1) in a typical livestock dairy farm, (2) in the most relevant dairy countries and (3) as a N-fertilizer supplier.