Psychrometric effluent water evaporator is a low cost zero discharge system. Many industrial processes produce abundant quantity of wastewater.
This wastewater is to be treated to prevent any damage to the aquatic life in the receiving water body. The wisdom of conventional effluent treatment plant is to convert soluble pollutants into solid phase, separate them from wastewater and finally this treated effluent is discarded.
But, in zero discharge system, instead water is separated from effluents and pollutants are converted directly into the sludge. Moreover, there is no liquid effluent remaining for discharge; hence it is termed as the zero discharge technique.
To achieve zero discharge objectives, there are two types of systems available in the market, i.e., (a) Reverse Osmosis (RO) system, and (b) Multiple Effect Evaporators (MEE).
Here, Psychrometric Evaporators can be the third alternative. It is highly energy efficient and effective with very low operating cost.
In psychrometric evaporation, air and water are kept in intimate contact with each other. Evaporation of water takes place by diffusion process at the wet bulb temperature of air, so that heat required for evaporation is very low grade, hence any waste heat produced in plant processes having temperature more than 50oC can be employed.
The psychrometic evaporation system is made of mainly two equipments in which one is psychro-evaporator, where, by principle of diffusion, water evaporates by utilizing the sensible heat of warm effluent.
In another equipment, i.e., effluent preheater, a suitable type of heat exchanger, waste heat is transferred from hot vapours, fluids, liquids or hot gases into the effluent to make it warm. The process of waste heat transfer and its utilization is repeated in every cycle.
In short, Psychrometric Evaporator with assured and lowest possible cost of evaporation of wastewater is very effective and economical zero discharge method. Moreover, it is utility (hot as well as cold) saver, energy saver, space saver and capital cost saver.