Industrial wastewater has become a major problem due to high concentrations of numerous harmful and hazardous pollutants, particularly heavy metals (HMs). Heavy metal pollution and its consequences for human health and the environment have increased interest in developing low-cost, long-term remediation technology. To remove heavy metals, various conventional physicochemical and green biological methods are used. This review article examines both conventional and biotechnological approaches for removing HMs from wastewater and rates their efficiency. The most appropriate technique for removing heavy ions from wastewater is determined by a number of factors, including operation cost, initial metal ion concentration, environmental impact, pH values, chemicals added, removal efficiency, and economic feasibility. These methods include adsorption treatments using various adsorbents, membrane treatments, chemical treatments, electric treatments i.e. electrochemical treatments. In general, chemical, adsorption, and membrane methods are the most practical method addressed in the literature. It has been noticed that there is a clear knowledge gap in the performance of treatment methods for the removal of heavy metal ions from real wastewater because most studies used synthetic wastewater in which one or few metal types are present. Accordingly, additional research should be conducted using real wastewater for treating different contaminants. More research on introducing cost-effective materials and methods for heavy metal removal from wastewater should be carried out. The best techniques for recovering metals with minimal environmental impact and low cost are still being developed and should be considered in future research.