Industrial water treatment facilities cover a multitude of activities as part of the purification process before water can be returned to rivers and municipal drainage systems. Waste water is treated to cover neutralization, coagulation, sedimentation, odour control, fluoridation etc. with water passing from one process tank to another, these varying in shape and size depending on volumes of water to be treated. Tanks are sometimes raised on structures to make best use of space and to suit process flow activity. The relating interconnected pipework and valve equipment is also very complex covering tank filling, injection of additives and variable discharge points and backwashes. Ladders usually run up the tank sides providing top access for regular maintenance and cleaning. This model represents a three elevated tank process prior to sludge settlement.