Current Works in Mineral Processing

Download PDF (1653.1 KB) PP. 11 - 21 Pub. Date: September 1, 2020

DOI: 10.22606/cwimp.2020.22001

• Shadrack Fosu^*
  University of Mines and Technology, Tarkwa, 237, Ghana
• Darlington Jerry Yawson
  Zeal Environmental Technologies Limited, No.4 Beachmasters Drive, Harbour Access Road, Takoradi, Ghana
• Clement Owusu
  University of Mines and Technology, Tarkwa, 237, Ghana

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.

coagulation, pH, computer simulation, visual basic programming, process control, water treatment

[1] Linder, K. and Zachman, B. (2009) “Getting Optimized: Optimize Coagulation and Flocculation”, American Water Works Association, Vol. 35, No. 4, pp. 8-9.

[2] Bello, O., Hamam, Y., and Djouani, K. (2016), “A comparative study of prediction models for Coagulation process in drinking Water Treatment Plants”, Int. Journal of Applied Sciences and Engineering Research, Vol. 5, No. 6, pp. 1-9, ISSN 2277-9442.

[3] Cox, C., Fletcher, I. and Adgar, A. (2001), “ANN-based sensing and control in the water industry: A decade of innovation”, In Proceedings of the IEEE International Symposium on Intelligent Control, Mexico City, Mexico.

[4] Koohestanian, A., Hosseini, M. and Abbasian, Z. (2008), “The separation method for removing of colloidal particles from raw water”, American-Eurasian Journal of Agricultural and Environmental Science, Vol. 4, No. 2, pp. 266- 273.

[5] Anon. (2018), “Conventional Treatment”, https://iaspub.epa.gov. Accessed: February 4, 2018.

[6] Gebbie, P. (2006), “An operator’s guide to water treatment coagulants”, In 31st Annual QLD Water Industry Workshop—Operations Skills, University Central Queensland – Rockhampton, pp. 14-20.

[7] Minkah, P.E., Fosu, S., Ndur, S.A., Asante, E.O., 2018. Computer simulation and modelling of chlorine monitoring and regulation system in water and wastewater treatment, 3 (1), pp. 69-78.

[8] Ashery, A.F., Radwan, K. and Rashed, M.I.G. (2011), “The effect of pH control on turbidity and NOM removal in conventional water treatment”, In Proceedings of the Fifteen International Water Technology Conference, Alexandria, Egypt, pp. 28-30.

[9] Bourke, N., Carty, G., O’Leary, G., Crowe, M., Page, D. (2002), “Water Treatment Manuals-Coagulation, Flocculation & Clarification”, Published by the Environmental Protection Agency, Ireland, pp. 14-19, ISBN: 1- 84095-090-0.

[10] BaiChuan, C., BaoYu, G., ChunHua, X., Ying, F., Xin, L. (2009), “Effects of pH on coagulation behaviour and floc properties of Yellow River water treatment using ferric based coagulants”, Chinese Science Bulletin, Vol. 55, No. 14, pp. 1382-1387.

[11] Hu, C., Liu, H., Qu, J., Wang, D. and Ru, J. (2006), “Coagulation behavior of aluminum salts in eutrophic water: significance of Al13 species and pH control”, Environmental science & technology, pp. 325-331.

[12] Kuphaldt, T.R. (2008), “Lessons in Industrial Instrumentation” Creative Commons Attribution/PA Control. Com, pp.491-2512.