Since the advent of membrane technology applications for large-scale commercial seawater desalination in the early Eighties, two critical issues in the application of the technology have emerged and persisted that drastically affected the way plant owners and operators managed these vital water production utilities, and subsequently impacted the total cost of water. The issues are the unpredictability and incidence of membrane fouling and the attainability of water conversion rates above 50%.
This paper attempts to show how the inadequacy of current methodology, innovation and field experience led to the establishment and validation of a novel approach applying certain corrections to the industry-standard performance measurement methodology (ASTM D-4516-001), based on site-specific plant operating conditions, resulting in an analytical method for early-warning detection, measurement, monitoring and effective management of membrane fouling development in real-time. The originality, simplicity and applicability of this innovative approach are exhibited in open-surface plant case studies of 5 trains from 3 different SWRO desalination plants in the Arabian Gulf. The studies are based on historical operating data and SDI15 profiles of feed water, covering many years of operation of these plants. The plants feature different membrane configurations, models and manufactures. The data is evaluated comparatively using both the standard ASTM normalization method, as well as the proprietary corrected parameters based on site-specific conditions of each plant. The result is the establishment and constant monitoring of membrane fouling or non-fouling status for each case in the study and the measurement of its magnitude in real-time as the percentage differential between the two normalization techniques. This differential, known as the Fouling Monitor (FM), is then compared to the ASTM-normalized flux decline trending analysis, as well as the SDI15 profile of that plant, considered by many as a critical fouling indicator.
This results of these plant case studies will show that the SMART approach, unlike most standard fouling management practices is capable of detecting, measuring, monitoring and managing any fouling or scaling development that may occur in the system before it can cause significant and often irreversible losses in membrane performance characteristics. The overall and long-term benefits will be reflected into minimizing the overall cost of water.