DETERMINING THE BEST INTAKE BLENDING SCENARIO OF SEAWATER AND TREATED SEWAGE FOR POTENTIAL REVERSE OSMOSIS DESALINATION IMPROVEMENT (CASE STUDY: UNTUNG JAWA ISLAND)

Abstract

The seawater desalination using Reverse Osmosis (SWRO) has overcome the increasing potable demand in Untung Jawa Island. However, the drawbacks are linked to high operational and maintenance requirements. The decline of seawater ecosystem harmony around the intake pump and brine discharge area also worsens. Thus, the reuse of treated sewage (TS) blended with seawater (SW) intake for decreasing feed water pollutant load is becoming a viable option to tackle this problem from the source. The digital simulation for SWRO modeling was necessary to be carried on due to time and cost efficiency, plant availability, and experiment complexity. The study’s objectives are to validate the simulation software, predict the potential improvement of SWRO by intake blending model, and determine the best intake blending scenario that suitable for SWRO Untung Jawa Island. The method of this study is based on secondary data collection and digital data processing to simulate existing condition, potential plant integration, and ten variations of intake blending using WAVE Design Software. It continued with the plot-graph and reduction percentage data analysis of SWRO variables from intake blending model. The output shows that existing condition result from software simulation is in the range of secondary data. Plant distance and capacity make the plant integration possible; however, the additional utilization of Sewage Treatment Plant (STP) advanced treatment is required. Through the intake blending model, the higher percentage of TS has potentially reduce SWRO technical variables. The study concludes that WAVE Design Soft are was applicable for SWRO digital modeling. The intake blending model is expected to improve SWRO performance and seawater ecosystem harmony. The best SW:TS percentage for SWRO Untung Jawa Island intake is 70:30 (15.97:6.85 m3/h) with potential reduction of 30% brine rate and 19% brine TDS, 40% seawater intake rate, 13.9% overall feed water rate, 32.8 RO energy consumption.