I-Corps: Small-Scale Low-Temperature Multiple Effect Distillation for Brackish Groundwater Desalination Using Heat from Biomass Pyrolysis

New Mexico State University, Las Cruces NM

Investigators

Abstract

The broader impact/commercial potential of this I-Corps project is the development of a new kind of water desalination system that operates on renewable energy and is suitable for the small scale: individual farms or processing facilities, or small groups of houses. This system combines beneficial use of solid biomass wastes with production of high purity water and a marketable biochar co-product that can be used to offset water treatment costs. This project may enable feasible water desalination for those with difficult-to-treat, hard brackish water and those without easy access to the electricity or the replacement membranes needed for reverse osmosis systems. Water desalination is a multi-billion dollar industry worldwide and is growing steadily to meet expanding demands for fresh water. New system designs create more options for the industry to find environmentally and economically sustainable water treatment solutions. This I-Corps project is focused on the identification of end users and potential licensees for a low-temperature multiple effect distillation (MED) system that derives its energy from pyrolysis of waste biomass such as agricultural residues, food processing wastes, and urban yard waste. In MED systems, heat is used to boil water and the heat of boiling is recycled from one evaporator to another. Advantages of low-temperature MED operation conditions are that hard brackish water is less likely to scale, hot water from a variety of potential sources can be used for the heat of boiling, and there are no membranes to replace. Current research has focused on the chemical engineering simulation of the entire pyrolysis-MED process and the development of a laboratory-scale prototype to study the effects of water chemistry on desalination performance. Early results suggest that this type of unit has strong potential for use in areas with limited access to reliable electricity and abundant supplies of unused biomass such as rural agricultural communities, especially in the developing world.