Organic solid waste management and the removal of harmful heavy metals continue to be global concerns. In recent years, the use of additives for the improvement of organic solid waste composting has garnered wide interest as an efficient, low-cost alternative for eliminating or reducing the toxicity of heavy metals from organic solid waste. Widely applied additives include natural minerals as well as some waste and by-products. The increasing use of additives in composting has led to increased research about the composting process and improving the quality of the final product. Chapter 11 begins with an introduction to the global perspective on heavy metal contamination and conventional approaches for the removal of heavy metals. Then it covers the performance and mechanism of some of the typical additives on heavy metal immobilization. Finally, the effect of assistive utilization on the physiochemical changes during bioprocessing of solid waste is presented.