Cycles of carbon, nitrogen and phosphorus in poultry manure management technologies - environmental aspects

Poultry manure (PM) has become a serious environmental problem due to large scale of industrial production and unsustainable management, causing emissions of greenhouse gases (GHGs), odors, leakage of nutrients as well as inorganic, organic and biological pollutants. The main goal of this review was to get a better understanding of carbon, nitrogen, and phosphorous cycles in processing of poultry manure with the most common technologies such as composting, anaerobic digestion, or thermal processes, e.g. pyrolysis. The carbon contained in organic matter (ca. 31%) is mineralized and humified under aerobic conditions (matter recovery) and/or converted into biogas under anaerobic conditions (energy recovery). PM as a feedstock for pyrolysis to obtain biochar may effectively store and prevent C, thus contributing to climate change abatement. During composting, nitrogen is reduced from the compost mixture by leachates in the form of NH4+, NO3- or gaseous emissions of NH3, N2O, N-2. The C/N ratio is also decisive parameter. Most environmental threats of unmanaged PM result from ammonia and nitrous oxide emissions, being higher for PM compared to cattle and cow manure independently of technological processes. The phosphorous in PM is mainly inorganic (32-84%). Using untreated manure as a fertilizer does not allow taking up high doses of phosphorus contained in poultry manure, so the excess accumulates in the soil and then leaches into groundwater. Biochar and struvite are an alternative to storage and source of high concentrations of phosphorous. Cycles of carbon, nitrogen and phosphorus are an integral effect of technologies used for PM management.

Automated summary

Poultry manure management is an environmental problem, and the cycles of carbon, nitrogen, and phosphorus play an essential role in the processes of composting, anaerobic digestion, or thermal treatment.