Abstract

There are various methods like composting, combustion, gasification, pyrolysis, and anaerobic digestion to convert animal wastes that harm the environment into various bio-products. Horse manure containing lower ash and higher rate of lignin compositions can be potentially reuse as a valuable feedstock in anaerobic digestion method to produce nutrient-rich digestate (bio-fertilizer) clean and cheap biofuels, and bio-energy to replace the cost effective fossil fuels which not only make climate change but harms our health by generating toxic emissions and contamination of soil and water. Therefore, converting bio wastes into useful green resources especially using anaerobic co-digestion is necessary to reduce their adverse environmental impact and can contributes towards the achievement of sustainable development goals (SDGs) 2, 3, 5, 6, 7, 9, 12, 13 and 15. As can be seen today, various animal manure types have begun to be used in different situations for their green benefits. This review aimed to provide an overview of the transformation of horse manure into compost, biogas in terms of its preferability as a renewable energy source or a value-added product that mitigate the environmental problems and contribute to the SDGs specially 7, 9, 12, and 13. The potential of animal manure to produce biomaterials, organic acids, biofuels and bioenergy is clear. Therefore, bioprocesses or biorefineries using this biomass as raw material may be promising in the near future in the context of bioeconomy, may help increase renewable energy production and may become capable of promoting innovation that boosts the value of livestock-derived organic fertilizers. There are still needs to extend the development of technologies for converting on-site bio waste resources to useful forms, exploring new and safe biological conversion pathways and bio waste processing methods.