Modification of Volume Silica Analysis Method in Water Samples to Reduce Hazardous Wastewater at Badak LNG Laboratory

Abstract

Volume of hazardous wastewater generated from analysis of the Badak LNG laboratory activities was found around 1.93 tons with an average of 161 kg/month in 2018 where 27% of this total wastewater came from silica analysis activities. Hence, many efforts have been done to reduce the amount of hazardous wastewater. In this research, the silica analysis activities have been carried out using American Journal of Public Health (APHA) 4500-D Heteropoly Blue method by modification of the volume from the silica content of water samples and reagents at 75%, 50%, and 25% (or ¾, ½, and ¼) recipes. Moreover, in the testing and validation phase, the measurement of silica levels in all samples has been performed using UV-Vis spectrometer at a wavelength of 815 nm. These modifications have included parameters of linearity, precision, accuracy, limit of detection (LoD), and limit of quantitation (LoQ). It was found that the volume modification for all samples have fulfilled the required parameters from association of official analytical chemists (AOAC) in linearity, accuracy, and precision. For instance, sample with ½ recipes showed coefficient of determination (R2) of 0.9997%, an accuracy of 103.80, and precision (%RSD) value of 0.524. Indeed, LoD and LoQ values for this sample were found to be 0.004 and 0.008. Modification to the volume of ½ recipe was particularly chosen because it was produced the minimum amount of liquid waste remaining at 8.25 mL with the test Duplo analysis. These results demonstrated that silica analysis activities can be used for reduction of wastewater.