Development of sustainable poultry waste management using integrated microalgae cultivation: Towards performance, resource recovery and environmental impact

This study aimed at developing a sustainable waste management from poultry farm by integrating microalgae cultivation with the anaerobic digestion effluent of chicken wastes (ADEC_W). The analysis was focused on system performance, resource recovery and environmental impact of microalgal biomass-derived added value products. Laboratory-scale of three different systems, i.e. suspended microalgae, biofilm microalgae and the control as no microalgae seed added, was conducted under outdoor climatic conditions in Thailand. The results clearly showed that microalgae system was successfully developed with high treatment performance and potential renewable energy production for the ADEC_W. Compared to the control, it was demonstrated that most removals of nutrient and organic pollutants were achieved through microalgal assimilation. Biofilm microalgal system was capable for removing NH₄ ⁺-N, PO₄ ^3--P and dissolved COD of 97 %, 93 % and 75 %, respectively at the cultivation time of 14 days, while for suspended microalgal system these were 92 %, 87 % and 68 %, respectively. Biofilm microalgal system also showed advantages of higher biomass production and simple harvesting of biomass, due to it tightly attached on supporting material by the matrix of extracellular polymeric substances (EPS). Moreover, the analysis of potential electricity generation and environmental impact highlighted the promising sustainability of microalgae-based poultry wastes treatment as microalgae provided significant potentials for electricity generation and CO₂ reduction. The analysis showed that with nationwide egg-laying hen farms in Thailand, the total electricity generation can be as high as 72 GWh/year with the total CO₂ reduction capacity of 99 kton CO₂/year, while CO₂ emission from electricity generated by microalgal biomass is at least 29 % lower than conventional fuels. The study offers a promising waste management alternative with great potential to achieve efficient treatment and valuable resource recovery for poultry farms in the future.