<p>A water treatment assembly breaks down chemical residues present in lakes or lagoons by a photo-catalytic process. Water is sucked by a submerged pump (3) to the surface through an inverted funnel (2) and riser pipe (4). At the top of the riser pipe (4) water flows through a solid-phase fixed photo-catalytic converter of titanium dioxide (10) in the upper reactor section (5) and over the phase-bound catalyst (9), which is held in place by a number of segmented concentric (10) rings. The catalyst substrate (6) is situated in a shallow, hollow truncated cone surrounding the riser pipe which drains to a dish (7) and is discharged (8) through horizontal outlets (13).</p>
