Nowadays ecology aspects are very crucial. They apply to all areas related to human life. The development of ICT (Information Communication Technologies) means that ecological issues are becoming increasingly important. Thus Green Computing or sustainability is not only the operational energy consumption of computing equipment but also it must take the product life cycle into consideration, from production to operation to recycling. In this study the authors are taking into consideration the role of Green Computing and Green Internet Of Things. The major challenge in Green Computing and Green Internet Of Things is the recyclability of the hardware, software, computer items such as cartridges and toners. Moreover, the save of energy is important as well. This study is interdisciplinary. The knowledge about reverse logistics of computer hardware needs specific management. That is why the knowledge management of green computing is a topic that is not widely discussed, but it is very important because it has a strong impact on the existence of Earth.