The Underlying Problems of Putrefaction

Typically, slurry will become a problematic waste product when conversion takes place by means of putrefaction processes. This involves decay under anaerobic conditions, i.e. in the absence of oxygen. Anaerobic conversion of slurry leads to the development of malodorous gases, including hydrogen sulphide and ammonia, and (odourless) methane gas. Also problematic, the odour carriers in manure – indole and skatole (3-methylindole) – attract harmful insects. These insects lay their eggs in the slurry, and the subsequent larvae often remain in the slurry when it is applied on the fields, leading to crop damage and the need to apply pesticides. Furthermore, the valuable substance ammonium nitrogen is lost in the anaerobic slurry, because ammonium is converted into ammonia, through volatilization, and consequently is no longer available as a nutrient for plants.

Oxygen through Aeration or Optimized Decomposition 

The conventional method of introducing oxygen into the slurry involves mechanical aeration by means of stirrers or compressors. However, this technical method becomes problematic when dealing with large quantities of slurry which cannot be stirred effectively every day. Floating layers then quickly form, further sealing off the slurry from the oxygen supply and thus strengthening the anaerobic environment. Also, the annual energy costs for stirring/agitation operations can be considerable.

But there is another way! The simple and natural solution to turn slurry into a valuable organic fertilizer involves activating decomposition processes in the slurry which only take place with oxygen. The decomposition processes involve mold fungi, yeasts and many other microorganisms; include several biological processes which are absolutely vital to maintaining a state of equilibrium in nature. Mold fungi very quickly bind any ammonia which is present in the first stage of the decomposition process to form ammonium nitrogen, which is subsequently available to plants as a slow release source of nitrogen. The harmful and unpleasant biogases are also largely eliminated, providing for a noticeable difference in the pit/lagoon and during application. Healthy, decomposed (rotted) slurry thus constitutes an important element of a closed substance cycle management system which benefits the soil, plants, animals and humans alike.