The influence of beach well and deep ocean intakes on TEP reduction in SWRO desalination systems, Jeddah, Saudi Arabia

Transparent expolymer particles (TEP) are believed to be a key organic compound that leads to membrane biofouling in SWRO systems. The sticky nature, high surface reactivity and micro-gel character of TEP play a major role in a membrane fouling, because deposition on the membrane surface acts as culture media for bacterial growth and as a depositional substrate. In turn, the TEP contributes to biofilm formation and membrane clogging with time. The removal of TEP at early stages of the desalination process is important to avoid any adverse effect on membrane operation. The intake system can play a significant role in TEP reduction. In this research, the impact of intake systems on TEP reduction was investigated. Two RO desalination plants in Jeddah, Saudi Arabia were studied. One of the SWRO desalination plants uses a deep-open ocean intake (9 meter depth) and the other uses four wells. Water samples were collected from the seawater surface, the intake, and after the pre-treatment processes. The efficiency of TEP removal by each treatment stage was evaluated. Organic compounds, bacterial and algae concentrations were determined for both sites. The results revealed that the use of well intake system reduced the TEP significantly compared to the raw seawater. By comparing the TEP concentrations in the surface seawater to those determined in the deep intake, it was found that the particulate TEP concentration was 70% lower in the deep intake, but colloidal TEP concentrations were much higher. These data provide insight into improved design of SWRO intake systems that take into consideration potential TEP occurrence and reduction scenarios.