Animal waste such as fecal material from swine, chicken, turkey, and cattle is converted into useful forms such as
fertilizer, other types of soil builders, and even
nutrient feed additives. Devices, systems, and methods are provided that allow economical conversion and in many instances, alleviate the production and release of undesirable gases such as
sulfide and
ammonia. In one embodiment, undesirable anaerobic and
facultative anaerobic bacteria are killed at a greater rate than desirable soil compatible
aerobic bacteria. The use of low temperature killing diminishes off gassing commonly associated with other techniques, and the use of gas
trapping additives such as zeolites provides enhanced soil building qualities such as slow release of
nitrogen and slow release of
moisture to soil. The methods allow convenient adjustment of composition, allowing conversion of waste into tailored designer
fertilizer suited for particular soils. Other embodiments provide other soil building qualities as well as
nutrient qualities for feedstock used in
animal husbandry such as
aquaculture.