Laboratory Technique Enhancement for the Analysis of Geothermal Fluids in EDC Geothermal Fields and Its Impact to the Overall Efficiency of the Laboratory Analytical Processes

Abstract

This study aims to improve the current analytical procedures of EDC laboratories in terms of sample volume requirement, analysis speed, waste generation and environmental impact to improve the overall productivity of its analytical processes. Inductively Coupled Plasma- Optical Emission Spectroscopy (ICP-OES) an analytical technique generally used for the analyses of metals with an advantage of improved analysis speed and reduce analytical volume requirement is the method proposed to succeed the current methods used in the analysis of Boron (Titration and UV-Vis Spectroscopy) , SiO2 (UV-vis spectroscopy), and metals (AAS). Current procedures used for Boron, Silica and metal analyses are time consuming, with longer chemical exposure due to extended sample preparation time and high chemical waste producer. In this study, several verification studies to ensure the applicability of ICP-OES in geothermal brine matrix and comparative studies between ICP-OES and current methods to assess the degree of agreement of the methods were conducted. The results of the verification studies showed that ICP-OES is a good technique for the analysis of metals, Silica and Boron in terms of linear dynamic range, detection limits, accuracy and percent recovery in both low and high saline geothermal fluids. Moreover, proficiency test result showed that the result provided by the new method is precise when compared to the results of other laboratory and accurate as shown by the high recovery percentage. With the positive results in the verification and proficiency testing, the transition to adopt ICP-OES as a new method for EDC laboratories yielded several benefits. The method reduced the volume requirement for B, SiO2 and metals (Na, K, Ca, Mg, Fe, Mn, Rb, Li, Al) analyses down to 100mL from 700mL (~86% reduction), analysis time by 88% and analytical cost to 70%. Volume reduction significantly lessened the effort in terms of handling and mobilization during sampling, shipping and logistics costs, the amount of waste generated by the laboratory, the chemical exposure of the analyst due to the new method, and heightened laboratory productivity as shown in the decrease in sample preparation and analysis time. Still, this volume requirement is limited only to the above-mentioned parameters; additional volume would be required for a complete suite analysis of geothermal samples.