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Current Works in Mineral Processing
CWiMP > Volume 2, Number 2, September 2020

Computer Simulation and Control of a Theoretical Coagulation pH System in Water Treatment

Download PDF  (1653.1 KB)PP. 11-21,  Pub. Date:August 17, 2020
DOI: 10.22606/cwimp.2020.22001

Author(s)
Shadrack Fosu, Darlington Jerry Yawson, Clement Owusu
Affiliation(s)
University of Mines and Technology, Tarkwa, 237, Ghana
Zeal Environmental Technologies Limited, No.4 Beachmasters Drive, Harbour Access Road, Takoradi, Ghana
University of Mines and Technology, Tarkwa, 237, Ghana
Abstract
Coagulation is an important process in water treatment operations. Inorganic coagulants such as aluminium salts consume alkalinity and may necessitate the addition of alkaline agent such as lime during coagulation. The pH required for coagulation is very critical. Particularly, aluminium salts serving as a basis for this work are most effective around a pH range of 5.5-6.5. It is therefore vital to attain this pH after the coagulant has been added. In this study, a typical coagulation pH control application called CoagiT has been developed. CoagiT seeks to maintain the optimum pH necessary for effective coagulation in water treatment. The application was developed particularly for application in Ghana using instrumentation and control principles and Visual Basic (VB) programming algorithms. This application can enhance learning by integrating the theoretical cogitation of control process with tactile nature of the plant. The application can operate in both closed-loop manual and automatic control modes. In the manual mode, when the measured pH value of the coagulation water is not equal to the set point pH, the application alerts an operator (by sounding an alarm) and suggests the percentage by which the lime supply rate should be adjusted to achieve the set point. In the automatic mode, the application automatically adjusts the lime supply rate to achieve the set point pH with the help of a pH transmitter and a pH indicating controller. CoagiT may be a useful simulation tool to provide user graphical windows environment in reducing the problems associated with ineffective coagulation due to improper pH control during water treatment.
Keywords
coagulation, pH, computer simulation, visual basic programming, process control, water treatment
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