Environmental Impact Cost Analysis of Multi-Stage Flash, Multi-Effect Distillation, Mechanical Vapor Compression, and Reverse Osmosis Medium-Size Desalination Facilities

In response to increasing global water demand, desalination has become an important source of water in many regions of the world. The objective of this research is to compare four different desalination methods operating at a production capacity between 100 and 200 m/d: 1) multi-stage flash (MSF), 2) multi-effect distillation (MED), 3) mechanical vapor compression (MVC), and 4) reverse osmosis (RO). Brine disposal and energy consumption for treatment are also discussed in the paper. The source water and brine disposal requirements for each method vary based on system efficiency. As a system’s treatment efficiency increased, the source water requirement decreased and the salinity of the brine solution increased. RO was the least energy intensive treatment method, requiring 3-5.5 kWh/m. MED and MVC had similar energy requirements at 6.5-12 kWh/m. The least efficient treatment method was MSF, requiring 13.5-25.5 kWh/m. High salinity and large energy requirements can be mitigated by pairing the desalination facility with a waste water treatment plant. Effluent can be mixed with the brine to reduce salinity and thermal energy can be supplied to reduce energy demand.