ELEKTROKOAGÜLASYON YÖNTEMİYLE KAĞIT ATIK SUYU ARITIMINDA pH KONTROLU.

In this study proportional integral derivative control of pH which is the output variable of paper mill wastewater treatment process with electrocoagulation has been performed. Flow rates of 0.1 M HCl and 0.1 M NaOH solutions have been chosen as manipulated variables. Firstly dynamic analysis and system identification studies have been carried out. pH data was collected by giving step changes to acid and base flow rates and auto regressive moving average with external input models were obtained by using recursive least squares method for each process where pH affected by acid and base flow rates respectively. Models were used in theoretical proportional integral derivative control program coded in MATLAB to determine optimum proportional integral derivative controller parameters by trial and error method. These parameters were then used in real time proportional integral derivative controller coded in MATLAB/Simulink to perform experimental studies. When coordinated control is applied to process by using acid and base flow rates as manipulated variables, pH value ranged from 5 to 11 and it is shown that the highest removal efficiency of turbidity and colour are 98.6% and 99.4%, respectively. [ABSTRACT FROM AUTHOR]