If not captured, CH4 contributes to global warming as a greenhouse gas. Nitrogen Manure contains several forms of nitrogen, which are continually transformed by microbial activity. As with carbon, the nature and extent of these transformations are affected by environmental conditions such as temperature, pH, moisture, and oxygen concentration. Organic nitrogen Most organic nitrogen is protein, and can be of plant, animal, or bacterial origin. The organic nitrogen in urine is primarily urea.
Microorganisms transform ammonia to nitrite and then nitrate through the process of nitrification .
This is an oxidation process which is therefore only significant in aerobic systems. Although this is a two-step process, formation of nitrite is normally the limiting step, so most of the oxidized nitrogen is in the nitrate form. Nitrates can be converted to nitrogen gas through the process of denitrification . This is another microbial process which occurs under anaerobic conditions. Some biological waste treatment systems are designed to reduce nitrogen levels through a sequence of aerobic and anaerobic processes.