LAUSR

Abstract This paper aims to (1) examine the challenges in the compost facilities of the Kingdom of Saudi Arabia (KSA), (2) optimize the composting techniques using indigenous natural zeolite and locally produced biochar from agricultural residues and (3) evaluate the environmental and economic benefits of optimized food waste composting. In KSA food waste is the most abundant stream of municipal solid waste that contribute up to 50% of the total waste. The landfill disposal of this waste results in several environmental and public health issues. Resource recovery through composting is one of the best approaches for treating such nutrient-rich organic waste. There exist several facilities in KSA for the conversion of food waste to compost using conventional methods of compost piles and trenches. However, none of the produced compost is capable of improving the quality and fertility of sandy soils and the growth of the crops due to limited values of organic matter, nutrients and water holding capacity along with high moisture contents, nitrification index, weed seed contents and ammonia emissions. In KSA, vast reservoirs of natural zeolite are available near to Jeddah city. Similarly, in KSA the most cultivated tree is date palm with more than 22 million date trees that would provide sufficient feedstock for biochar production. Therefore, diverting food waste from landfills to optimized composting facilities using natural zeolites and biochar could benefit the KSA economy with a total net savings of about US $70.72 million per year.