MEE (Multiple Effect Evaporator) is inevitable component of Zero Liquid Discharge plants. Use of new technology could replace MEE, reducing costs to 35 - 50%.
About
MEE is used to achieve Zero Liquid Discharge of wastewater. Due to high costs (capital and operational) achieving ZLD becomes unviable. Failure of plants will not only add costs to industries for compliance but also will contaminate natural resources. Hence there is a need of cost effective alternative to MEE, which can concentrate salts effectively and sustainably. Inorganic constituents of wastewater are concentrated using RO (Reverse Osmosis) units and product water is reused. As concentration of dissolved salts in feed to RO increases, power consumption goes up rapidly. Thus, after a particular point, use of RO becomes uneconomical and MEE has to be used to recover water. Evaporation systems are expensive and have very high power and steam demand. This increases cost per m3 of water recovered and makes ZLD unviable for the industries. Efficient solution using new technology can replace MEE. Special property of membranes, have been used applied effectively for this new technology. Salts can be concentrated using membrane filtration system by maintaining lower power demand and steam is not required. Particular property of membranes is used to concentrate salts by keeping feed pressure at lower values. This reduces power demand and cost of water recovered. Use of steam is eliminated and return on investment could be achieved in < 2 years. It also minimizes complex operations of MEE and related maintenance.
Key Benefits
Concentration of dissolve salts could be achieved in efficiently. Capital and operational costs for using MEE could be reduced significantly (up to 50 %). Existing seawater desalination plants can be augmented to increase recovery up to 2 times.
Applications
1) Seawater Desalination – Efficiency could be increased to 75% from 35 to 40% 2) Complete or partial replacement of MEE for ZLD plants treating industrial wastewaters