During drinking water treatment, the chemical dosing processes, such as coagulant dosing process, ozone dosing process and chlorine dosing process are usually manually operated based on the operator knowledge and experience. However, due to the variations of water quality, water flow and process operational conditions and characteristics of large time-delay and nonlinear for the chemical dosing processes, it is difficult to adjust the chemical dosages in time by operators to keep the treated water quality stable, especially during the periods of rapid and frequent variations of water quality, water flow and process operational conditions. Thus, the improvements of control methods for the chemical dosing processes are essential to the operation of drinking water treatment plants. The Xiangcheng Water Treatment Plant in Suzhou, China has been utilizing the automatic control for chemical dosing processes since February 2012. Automatic controllers are designed respectively for the coagulant dosing process, ozone dosing process and chlorine dosing process. After the implementation of automatic control, operators are not necessary to keep constant attention. In addition, due to the improvements of control accuracies for the chemical dosing processes, the chemical dosages are reduced on the premise of ensuring safe water. Thus, both of the human resource costs and material costs can be saved. The practical control results demonstrate the efficiencies of proposed methods.

Oxytetracycline (OTC) is one of the extensive use antibiotics in livestock. Untreated waste of livestock and poultry breeding discharged into the soil or applied to the soil, directly, lead to pollution of soil in antibiotics. Current antibiotics pollutes caused problem to cause social attention more and more. As soil is the main destination of antibiotics like other pollutants, the antibiotics would eventually be accumulated in the soil when they entered the environment, researching antibiotics in soil migration and diffusion in water environment is important. To analyze environmental risks in antibiotics, and to provide reference basis for antibiotic pollution control, OTC in soil adsorption process and mechanism are conducted. Research showed that first-order kinetic equation model, double constant equation model, and parabolic equation can describe the adsorption process of OTC in soil. Under PH=7 condition, the strongest adsorption and the maximum adsorption capacity are appeared. Adsorption of OTC in soil has a certain mobility, and there are certain security threats in surface water and groundwater environment.