Using polyethylene sleeves with forced aeration for composting olive mill wastewater pre-absorbed by vegetative waste

•Olive mill wastewater absorbed by green waste was composted in closed sleeves.•Thermophilic temp. were kept for 1 month, followed by 30–40 °C for extra 3.5 months.•Oxygen levels were controlled and the system was kept aerobic.•Sufficient moisture remained along the composting process.•The final compost was found suitable as an ingredient in growing media.