PILOT ASSESSMENT OF CORROSION AND ENCRUSTATION POTENTIALS ON GROUND WATER WELL MANAGEMENT IN PARTS OF LAGOS STATE SOUTHWESTERN NIGERIA

Abstract

Reports have shown that a series of boreholes had either failed, collapsed, or abandoned due to casing pipe damages and poor yield in parts of Lagos state and its environs. This have possibly resulted from the poor-quality underground water quality within these areas which could either be from extraneous contaminant or source rock within the area. Consequently, the preliminary study of this underground water was conducted to ascertain possible causes and amelioration processes. To this end, fifteen borehole samples were collected for various laboratory analysis to determine their physical and chemical parameters in order to assess the level of corrosion and encrustation induced by groundwater on borehole casing and screens pipes (mild steel pipes) that are mostly used for deep boreholes within the study area by means of Corrosion and Encrustation Index Parameter (CEIP) and other cognate parameters. The results of the analysis show that the pH value ranges from 5.2 to 6.9, Fe (0.43-2.80mg/l), Mn (0.1-1.2mg/l), TDS (86.0-392.0mg/l), DO (2.1-2.6mg/l) Chloride (Cl (6.8-53.0mg/l), temperature (25-30^oC) and Total hardness (22.0-226.0) respectively. Upon correlating the results with the Corrosion and Encrustation Index Parameter as well as the World Health Organization (WHO, 20O6) it was found out that the pH values, dissolved oxygen, manganese iron, and temperature might have contributed to the corrosion and encrustation activities on the pipe. It is recommended that materials such as UPVC high pressured polyvinyl chloride materials, high corrosion-resistant stainless pipes and corrosion-resistant paints can be used as an alternative to ameliorate the problems of corrosion and encrustation for the use of the groundwater drilling operators