# Towards Digitalization of Water Supply Systems for Sustainable Smart City Development--Water 4.0
## 3 Moving from Industrial Revolution to Water System Revolution  
Industry 4.0 is the fourth industrial revolution developed to meet multiple demands of additive manufacturing processes and has been implemented in multiple engineering fields such as provisioning of smart monitoring and control capabilities to water supply systems. A comprehensive study is taking place in this area. Figure 2 shows the four stages of the industrial and water system revolution. The industrial revolution can be traced back to its stem in manufacturing processes. It began with Industry 1.0, called the age of steam, involving the utilization of the energy from water and steam for production systems. Only a few products could be accomplished during this era, thus enhancing manufacturing activity led to the second industrial revolution called Industry 2.0. This revolution is also called the age of electricity where mass production with the use of electrical power was achieved. As illustrated in Figure 2, Industry 2.0 was revolutionized by the advent of information technology to automate production procedures. This led to Industry 3.0, which enhances process flexibility. More recently, studies and projects have been devoted to Industry 4.0, initially proposed in Germany [28]. This project is an initiative to revolutionize the manufacturing sector. This revolution consists of an integrated method for the use of emerging technologies which include cyber-physical systems (CPS), internet of things (IoT), cloud computing, artificial intelligence and automation to enhance productivity. This revolution offers a better way to use information, control, and communication theory to provide improved operations. The idea has been applied in some areas of engineering such as the medical field [29], smart logistics [30] and the energy sector [31,32]. As shown in Figure 2, the use of this concept is being proposed for the water sector. This is currently referred to as Water 4.0. Before the key drivers of Water 4.0 are addressed, an overview of the revolutions within the water system is presented. As shown in Figure 2, the first revolution in the water sector involved the use of local ad-hoc systems to pipe potable water in and sewage out of population centers. During the second stage, treating drinking water to kill infectious microbes and protecting users from diseases transmitted through the very success of Water 1.0 was accomplished through the use of large centralized infrastructure. Water 3.0 saw widespread adoption of computers and control in the water sector. One of the successes from such application is sewage treatment plants [33]. The current stage of revolutions in the water sector (Water 4.0) involves an integrated method for the use of emerging digital technologies, which include CPS, IoT, cloud computing, artificial intelligence, and automation to enhance water supply system operations. Water 4.0 provides a unique opportunity to identify a promising approach to addressing future management problems in water supply networks. It incorporates the primary features of Industry 4.0 such as digitization and automation to achieve a systemic water management context. Through the use of automation and increased integration of sensors (for pressure, flow and temperature measurements) and model applications (such as the hydraulic model of water networks), opportunity may be created to better understand water management problems in terms of their complexity and to illustrate the use of Water 4.0 in production, early warning and for the decision making process. Water 4.0 also provides a greater ability to optimize the management of the water supply system to achieve efficient use of scarce water resources. Therefore, utilizing the key features of Water 4.0 in enhancing water supply network management operations motivates the need to conduct more research in this area. However, in addressing this, the salient features of Water 4.0 need additional study.