Abstract: A process for the treatment of liquid waste biomass, especially liquid manure compositions, wherein the biomass is converted to a fertilizer product. The process at least includes a nitrification step including a first biological conversion stage wherein ammonium is converted to nitrite using nitritifying bacteria in an aerated reactor, and a subsequent chemical oxidation stage wherein nitrite is converted to nitrate by heating the liquid waste biomass in an aerated reactor under acidic conditions. The process is particularly suitable for treating liquid manure, because of the high ammonium nitrogen contents thereof, which render the process essentially self-regulatory. In addition a process for the treatment of liquid waste biomass wherein organic matters are converted to energy sources, referred to as biogas and green cokes, and wherein nitrogen is fixed in a fertilizer product in the form of ammonium nitrate, is provided, the process including the present nitrification process.