Water safety and purification are issues of great concern to people. Not all water is safe to drink outdoors. Excessive salt in water affects the quality of drinking water, so it is necessary to filter the water for drinking. In this article, you will learn about the dangers of excessive salt in water and how to filter the salt in water.
Sources of salt in water
The salt in water mainly comes from nature, human activities, and climate factors. Nature mainly comes from groundwater and rivers. When flowing through rock formations containing salt minerals, the salt in the rocks will dissolve into the water, such as sodium, potassium, calcium, and other minerals.
Using fertilizers and pesticides may increase the salt content in soil and groundwater, especially in over-irrigated areas. Some industrial processes (such as mining and chemical production) produce salty wastewater, which will increase the salinity of water bodies if discharged into the environment without treatment. There is also wastewater from households, businesses, and industries that contain salt, especially in areas where water softeners are used, and these salts may enter rivers and groundwater.
More water evaporates from lakes and reservoirs in arid or semi-arid areas, leaving higher salt concentrations. Aerosols and dust particles in rainfall sometimes contain salt, which will be deposited on the ground or in water bodies with precipitation.
What are the dangers of excessive salt in water?
Excessive salt in water does bring many hazards. For example, it affects human health, agriculture, industry, the environment, etc. The following will introduce you in detail based on these four impacts:
Impact on human health
Drinking high-salt water can lead to dehydration. This is because salt absorbs water from the human body, leading to dehydration. At the same time, if you drink high-salt water for a long time, it may cause symptoms such as high blood pressure, kidney disease, and gastrointestinal disease. Therefore, you need a reverse osmosis system to filter the salt in the water before drinking it safely.
Impact on agriculture
When you irrigate crops with water, if the water has too much salt, it may cause soil salinization, deteriorate soil structure, reduce fertility, and hinder crop growth. High-salinity water will inhibit the absorption of water and nutrients by crop roots, and will also seriously affect the yield and quality of crops. Therefore, you need to use appropriate methods to filter the salt in the water to ensure the healthy growth of crops.
Impact on Industry
High-salinity water can cause corrosion of pipes and other industrial equipment, thus shortening the service life of the equipment. At the same time, many industrial production processes have high requirements for water quality. High-salinity water may affect the normal operation of the production process, resulting in reduced product quality or equipment failure.
Impact on the environment
The discharge of high-salinity wastewater will increase the salinity of rivers, lakes, and groundwater, destroy the aquatic ecosystem, and affect the survival of aquatic organisms. Therefore, a high-salinity water environment will seriously affect the survival of carbon-aquatic organisms.
Does reverse osmosis remove salt from water
Reverse osmosis can remove salt from water. Because reverse osmosis is an efficient water treatment technology, it is a membrane separation process driven by pressure. During the reverse osmosis process, water molecules flow through the membrane on the low-pressure side of the membrane to the high-pressure side, while other ions, molecules, and particles dissolved in the water are retained by the membrane, thereby achieving water purification and separation.
Reverse osmosis is an efficient water treatment technology that separates dissolved substances and harmful impurities in water, such as salt, heavy metals, bacteria, viruses, etc., through a semi-permeable membrane. The pore size of the RO membrane is 0.0001 microns, which can filter most of the pollutants in the water.
According to the World Health Organization (WHO), the total dissolved solids (TDS) content in water treated with reverse osmosis can be reduced to below 50 ppm, while the TDS content of general tap water is about 300-500 ppm.
Therefore, reverse osmosis is an ideal choice for removing salt from water. There are many types of reverse osmosis systems on the market, and ITEHIL portable water filters stand out with their efficient reverse osmosis filtration technology and portable design.
Advantages of reverse osmosis:
- Efficient water purification
- Efficiently filters salt in water, with a filtration effect of up to 99%.
- Can filter out other harmful substances such as heavy metals, bacteria, and viruses.
- Filtered water is safe and healthy
- Convenient and practical
- Long filter life
- Wide range of applications
Disadvantages of reverse osmosis:
- The filter element of the water filter needs to be cleaned and replaced regularly.
- A certain amount of concentrated water will be produced.
Related: How does reverse osmosis system work
Other ways to filter salt from water
Distillation
Distillation can also remove salt from water. It mainly heats water and evaporates it, then condenses the steam to obtain pure water. Distillation takes advantage of the difference in the physical properties of water and salt. When you heat water, it evaporates. At this time, salt and most harmful impurities will not evaporate, and they will continue to remain in the residual liquid. The specific distillation process is as follows:
Distillation Process
- Heating: The raw water is heated to a boiling point and then evaporates.
- Evaporation: The water begins to evaporate, forming water vapor. Salts and other harmful impurities remain in the raw water and do not evaporate with the water vapor.
- Condensation: The water vapor is directed into a condenser, where it is cooled and condensed back into liquid water.
- Collecting Pure Water: The condensed liquid water is collected in a clean container and is usually free of salt and other impurities.
Advantages
- Efficient salt removal
- Wide range of applications
- Simple and reliable operation
Disadvantages
- High energy consumption
- Slow speed
- High equipment cost
Electrodialysis
Electrodialysis is a highly efficient method for desalination and water purification. It mainly uses the action of an electric field to remove salt from water. Electrodialysis uses the migration characteristics of charged ions in an electric field. By applying a DC electric field to water, cations, and anions will move to the negative and positive electrodes respectively. Electrodialysis systems use specific ion exchange membranes that are selectively permeable to cations and anions, which can separate these ions from water to achieve the purpose of desalination.
Working process
- Water inflow: Water containing salt flows into the electrodialysis unit.
- Ion migration: Under the action of the applied electric field, cations in the water move toward the cathode and anions move toward the anode.
- Ion separation: Cations enter the concentrate chamber through the cation exchange membrane, while anions enter the concentrate chamber through the anion exchange membrane. The ion concentration in the freshwater chamber decreases, while the ion concentration in the concentrate chamber increases.
- Collecting freshwater: The water in the freshwater chamber becomes purer due to the removal of ions and is collected as fresh water.
Advantages
- High efficiency and energy saving
- Wide application range
- Flexible operation
- Low demand for chemicals
Disadvantages
- Higher equipment cost
- Membrane fouling issues
- Limitations in handling high salinity water
Nanofiltration
Nanofiltration is a membrane separation technology that lies between ultrafiltration and reverse osmosis. It mainly uses nanofiltration membranes to separate dissolved substances in water. The pore size of nanofiltration membranes is 1-10 nanometers, which can effectively block larger molecules and multivalent ions and allow water molecules and some small monovalent ions to pass through. The selectivity of nanofiltration membranes depends on the chemical properties and pore size of the membrane material.
Working process
- Pretreatment: The water first passes through the pretreatment equipment to filter large particles and suspended matter to prevent the nanofiltration membrane from clogging.
- Pressurized filtration: The water is pressurized and sent into the nanofiltration membrane module under the action of the pump.
- Separation process: In the membrane module, multivalent ions and large molecular organic matter are retained on one side of the membrane, while monovalent ions and water molecules pass through the membrane and enter the water production flow.
- Collection and discharge: The water passing through the membrane is collected as fresh water, and the concentrated water containing the retained substances is discharged or further treated.
Advantages
- Removal of divalent ions
- Energy saving
- Selective desalination
Disadvantages
- Limited monovalent ion removal
- Membrane fouling
- High initial investment
FAQ
Which filter can remove salt from tap water?
Filters that can remove salt from tap water include reverse osmosis filters, distillation, nanofiltration (NF) filters, ion exchange systems, etc.
Does boiling softened water remove the salt?
Boiling softened water does not remove the salt. Boiling water is to heat water to boiling point, so that harmful microorganisms (such as bacteria and viruses) in the water are killed, but it does not change the concentration of dissolved minerals or salts in the water.
Does charcoal remove salt from water?
Charcoal is not effective in removing salt from water. The main role of charcoal (or activated carbon) in water treatment is to adsorb organic matter in water, remove odors, and improve the taste of water, but its effect on removing dissolved inorganic salts and ions is very limited.
Related: What Does a Carbon Filter Remove From Water?
Final Thoughts
Filtering salt from water can ensure safe drinking water. High-salinity water quality has a great impact on human health, industry, agriculture, and the environment. Therefore, removing salt from water is very important. I believe that after reading the above content, you have a great understanding of how to filter salt from water. I hope this information can help find more solutions to ensure cleaner and safer drinking water.
