A microfluidic assessment of seawater intake system in the context of marine life protection

Desalination is a climate independent source of water and its demand for production is growing worldwide due to ubiquitous impact of climate change. One important component of a desalination plant is its intake system, which is highly susceptible to clogging in a marine environment. Intake system requires special attention to manage impingement, entrainment and fouling by marine biota. High mortality rate of marine lives is a common occurrence in the process. Conventional intake systems are extracting raw seawater with a large quantity of marine organisms and debris. This study investigates an innovative solution to decrease the mortality rate of fishes and other marine organisms at those open-water intakes. The intake grill bars are to be replaced with novel rotating discs (modulated) with micro-scale structures engraved on its surfaces, in order to prevent microorganism and other marine foulant attachment. Preliminary investigation indicated that these microstructures inhibit bacterial settlement on its surfaces. A microfluidic experiment with patterned microwells showed that there were almost no settlements of E. coli up to 4 days. Computational Fluid Dynamics (CFD) simulations are carried out to understand the surface-near microfluidic conditions and its relation to dynamic stability of microorganisms. High shear and sharply fluctuating stress-strain rate bounded zones segregate the group settlement (gregariousness) of microorganisms along the path of its progression. This study also reviewed current seawater intake systems and evaluated their efficacy in terms of fulfilling their requirements.