The Hidden Complexity Of Surface Water Treatment Surface water treatment is often underestimated in its complexity. Unlike groundwater, surface water is a dynamic and biologically active system that presents a wide range of treatment challenges. These include: Highly soluble colour from fulvic and humic acids Algae and biological growth Extracellular polymeric substances (EPS) Bacteria and pathogens Colloidal matter Significant seasonal fluctuations In essence, surface water