DESALINATION

AWSE uses the latest highly optimized desalination methods to resolve water shortage in specific regions of Africa where surface water or ground water may not be sweet.

The production of potable water out of salt water is a complex process that requires the designing of desalination plants in order to remove minerals present in the water either by evaporation or physically by filtration with a Reverse Osmosis membrane (RO).

Osmosis is a movement phenomenon of solvent molecules through a semi-permeable membrane that separates two solutions having different solute concentration.

Desalination & Brackish Water Treatment

RO has various uses and serves municipalities and modern industries including pharmaceutical, food industries or boiler water used in power plants needing specific water profiles that can be delivered by RO plants.

This water purification process includes a semipermeable membrane which retains particles from water. The design of the plant will focus on three operational expenditures: annual chemical expenses, energy recovery that can reduce energy consumption down to 50% and membrane lifespan.

This unique water purification technology is a well-tried technology to desalinate sea and brackish water for industrial processes or human consumption with optimal results with well-managed expenses.

RO requires an additional post-treatment named remineralisation as low mineralized water has negative effects. Indeed, cerebrovascular disease and ischemic heart can be the consequence of drinking demineralized water (or rain water). An other adverse effect is water is potentially highly corrosive.

World Heatlh Organisation recommends 10 mg/L of Magnesium (US EPA does not limit the Mg content) and 30 mg/L of Calcium for drinking water as the highest desirable level and 50 mg/L as the maximum level.

The presence of boron in sea water and brackish water is found in much higher levels than freshwater and may not be adequately removed in a single reverse osmosis cycle (from 50 to 70% is removed at a first stage).
Boron is an essential nutrient for growth and development of plants and is used in agriculture as micronutrients in fertilizers but in large concentration is used as an herbicide, algaecide or pesticide. This chemical component is not currently present in drinking water regulations and therefore the public is not adequately protected from it. According to the latest information, EPA would not regulate this element as primary contaminant under the Safe Drinking Water Act because of not being enough present in common sources of potable water.

Seawater and brackish water can also contain endocrine disruptors, pharmaceuticals or toxins from marine algae which may not also be removed on a single RO cycle.

In order to avoid the presence of boron and other elements dangerous for health, AWSE adds systematically a second reverse osmosis cycle to guarantee the production of an extremely pure water, regardless to the increase of production costs, prioritizing health matters.

AWSE can offer economical plants and proven technologies for each kind of environment and requirements.

Other technologies can be used depending on the needs and the configuration of the environment such as:
– Thermal desalination Multi-Stage Flash (MSF)
– Thermal desalination Multi-Effects Distillation (MED)
– Thermal Vapor Compression (TVC)
– Mechanical Vapor Compression (MVC)

Desalination & Brackish Water Treatment

The common industrial desalination method requires consequent energy supply (3 to 5,5 kWh/m3) for the water to go through RO membrane which increases OPEX.
Alternative methods such as Multiple Effects Distillation consumes less energy (1,5 to 2,5 kWh/m3) for reducing OPEX and lower CAPEX compare to Reverse Osmosis. Such systems are highly reliable and very simple to operate: they require very low maintenance costs, can run 24H/day with a minimum staff to supervise operations.

AWSE delivers optimized sea water desalination solutions depending on the needs which are of great value for people and industries in Africa.

Please contact us to describe your project and submit your water analysis so we can suggest the best water treatment solution designed in accordance to your requirements.