Seawater Desalination

Seawater Desalination

Seawater Desalination

From water-makers to industrial sized Seawater Desalination Purification, we offer a full range of systems. We are manufactured to cut a large amount of salts and other minerals from seawater desalination using SWRO. Our equipment does the filtration by employing a high-pressure pump to salty water forcing it through semi-porous membranes denying salts and other organics from flowing through.

The membranes are only tasked to remove dissolved solids while dividing the feed water into purified water and rejected concentrated salts. The salts and other organics are thrown into the brine stream then flushed into a drain. At the end we have purified water that has 99% less dissolved salts. These sea water desalination SWRO systems have the power to purify extremely high TDS water.

Desalination plant SWRO systems are usable anywhere from yachts to municipalities. It’s important to choose the correct materials of construction to handle seawater (which is highly corrosive). TWA uses materials such as Duplex SS 2205, SS 2207 or Monet, and SS 904 to guarantee a longer operating life and less maintenance.

TWA has extensive experience desalting seawater all around the world. Our engineers consult for other manufacturers of desalination equipment. Take advantage of our ability. Contact Us today for expert, friendly service and top quality support.

Problems With Reverse Osmosis

Scaling occurs on RO membranes when the concentration of scale-forming species exceeds saturation, producing additional solids within the RO feedwater. Scalants include such chemical species as calcium carbonate, calcium sulfate, barium sulfate, strontium sulfate, and reactive silica. Since these species have very low solubilities, they are difficult to remove from RO membranes. Scaling decreases the effectiveness of the membranes in reducing the solids and causes more frequent cleanings. A scale on a membrane provides nucleation sites that increase the rate of formation of additional scale.

Methods to minimize scaling

Magnesium hydroxide tends to absorb silica, another scalant. Another softening procedure involves zeolite in an ion exchange process.
Often used with acidification, or by itself, are antiscalants. Antiscalants are chemicals added to wastewater to minimize scale carbonate or sulfate based scale. They consist of acrylates and phosphonates which inhibit the precipitation of carbonate or sulfanates.

Methods to prevent fouling

The second problem with reverse osmosis is with the fouling of membranes. Fouling occurs when suspended solids, microbes and organic material deposit on the surface of the membrane. Another problem is from colloidal sulfur, which when oxidized from H2S can foul RO membranes.
Coagulation is one technique that neutralizes the negative surface of the suspended solids, allowing the particles to cometogether. These large particles are then easy to remove from the water using filtration. The most common coagulants used are cationic polymers, inorganic salts, and aluminum and iron salts. Inorganic solvents tend to form large particles, while catonionic polymers require much less product for coagulation. Similar to coagulation is the clarification method, which destablizes suspended particles through charge neutralization. This is generally done by oxidizing iron and manganese and physically removing the precipitates in the manganese greensand bed.