Basically as explained previously, Waste Water Evaporators are designed to remove the solvents which can be any liquid with low boiling point or water from non-soluble solids and other solute heavy components. It is very much similar as what you would find in a distillation process whereby chemicals which are deemed to have the recovery and reusable value to undergo the process so that this will lessen the waste discharge and at the same time, minimize operating cost in the long run since the recovered materials can be returned back to the systems. Hence it offers a closed loop system which can serve as valuable unit of operation.
Waste water evaporators are widely used in different industrial processes especially the metal and electroplating industries and while refinements have been made on the design part, different engineering principles can be applied to improve it further. Vacuum application is one of it, as introduction of vacuum can help to lower the boiling point of the solvents, thus leading to increased efficiency of the waste water evaporators. Apart from the vacuum, another applied technique which is rather common is by using forced circulation usually achieved by using a centrifugal pump to feed the liquid into the evaporation chamber and as it enters the compartment in forced mode, the liquid is dispersed and flash off immediately. In effect, both vacuum and high pressure feed will help to increase overall efficiency and make the evaporators use less energy when in operation.
Efficiency of the waste water evaporators also depend on how the heating element is designed and constructed. Basically a few simple approaches are by using climbing film or falling film and the idea is to have tube arrangements that form the highest surface area available for heat transfers. For the heating media that passes through the tube or coil, typically steam is the preferred choice but in recent years, development of thermal oil has made its way to be applied in newer models of the evaporator units. Usually efficiency of a newly installed system can suffer due to scaling of the tube, excessive carry over of solute going to the condenser leading to flooding of the system and also poor maintenance is to be blamed as the root cause the decreases the life span and efficiency of the waste water evaporators.