The Design Of Sewage Treatment Control System

With the fast development of China's economy, the problem of resource and entironment is more and more serious, so that China's modernization construction is facing severe challenges. Especially, the phenomenon of China's water shortage and pollution has attracted the close attention, and the sewage treatment projects have been implemented immediately.At present, the majority of sewage treatment control systems in our country are low automatized, low secure and mismanagement, and the efficiency is commonly under the international standard. The problems must be solved are aeration control, data communication, monitoring and management.According to the sewage treatment project in an enterprise, an integration control system is designed including the locale control part, human-machine conversation part and long-distance information monitoring part. PLC, which is stable and reliable, is selected as the locale controller. The advanced Ethernet and GPRS technology are used to upbuild a network of management and monitoring. The same configuration and program are used to provide a friendly human-machine interface in the whole system. The efficiency of wastewater treatment is improved because the control system is designed with the view not only to the equipments' safety and economic operation, but also to the quality of monitoring, management and communication.The dissolved oxygen content in the contact oxidation tank is the key factor of wastewater treatment. The optimized adjustment scheme of dissolved oxygen setting value and human simulating intelligent control algorithm with the characteristics of simple configuration, legible physical signification and convenient use are designed to be used in the frequency conversion control during aeration process to overcome the difficulties of dissolved oxygen content control and its setting value. The simulation results show that the control method is effective, and the scheme is efficient, energy saving and cost saving. The data communication and automatic monitoring are realized, the difficulty of the aeration control is decreased, and the management level of sewage treatment is improved by the designed system. It has great realistic significance for solving environment pollution and energy crisis.