The biological processes improving fast are shown among the future technologies. In these processes which biological materials are used as degraders, raw wastes are processed to remove the contaminants in them. Biotechnological processes are used for wastewater treatment, gas treatment and disposal of solid wastes in environmental engineering. Also, these processes can be utilized for the production of biogas and hydrogen as new energy resources. For preventing environmental pollution in environmental engineering, activated sludge process, trickling filters, biotrickling filters, oxidation ponds, anaerobic treatment, composting units and biogas reactors are used extensively among the waste treatment technologies. In this review paper, the role of biotechnology on waste treatment was assessed and several treatment methods were investigated