Biomedical waste (BMW) contains pathogenic microorganisms that may severely harm the community and environment. Due to the Covid pandemic-2019, isolated wards at health care units and even due to the home treated patients; vast quantities of BMW are generated. Covid-19 converts even ordinary waste such as gloves, testing kits, and personal protective equipment into high-risk BMW. The appropriate disposal of such waste involves safety, affordability, and efficacy; hence can be considered a complex issue. A solution proposed in this article is an OSBMWTU (on-site biomedical waste treatment unit) by using microwave radiation. The possibility of enhancing the thermal effect of microwave radiation by using chemical additives was tested. The proposed machine reduces waste volume, inactivates microorganisms, and disposes BMW on-site. Findings suggest that adding butter spray to microwave radiation enhances thermal effectiveness by 43%, increasing treatment temperature while minimizing time, power, and running costs. The proposed machine will work automatically after filling the BMW, thus, minimizing the human involvement. It prevents bio-hazardous waste accumulation and decreases its volume by up to 80%. The designed machine is characterized by safety, low cost, and small dimensions. A machine that can handle 72 kg BMW/day can be set up on-site in an area of 1.5 m2. The suggestion of the proposed machine as a BMW management and treatment system will reduce environmental pollution due to BMW during COVID-19 and even after the pandemic.