Employs physical barriers like sand, gravel, or cartridge filters to trap suspended solids, sediments, and larger particles. Advanced systems may use multi-stage filtration to progressively refine water quality, ensuring clarity and reducing turbidity.

Targets harmful microorganisms—bacteria, viruses, and protozoa—using techniques like chlorination (adding chlorine compounds), UV radiation (disrupting microbial DNA with ultraviolet light), or ozonation (introducing ozone gas for oxidation). Each method balances effectiveness with safety for human consumption.

Adjusts water properties by adding coagulants (e.g., alum) to clump fine particles for easier removal, or chemicals to control pH, hardness, or specific contaminants like heavy metals. This step often enhances downstream processes like filtration or disinfection.

Utilizes semi-permeable membranes to separate impurities at a molecular level, offering precision in water purification:

• Reverse Osmosis (RO): Applies high pressure to force water through a membrane, removing dissolved salts, minerals, and organic compounds—ideal for producing ultra-pure water.
• Ultrafiltration (UF): Uses membranes with tiny pores to filter out bacteria, viruses, and fine particulates, often as a pre-treatment for RO or standalone purification.
• Nanofiltration (NF): Targets divalent and larger ions (e.g., calcium, magnesium) for water softening, bridging the gap between UF and RO in selectivity.
• Microfiltration (MF): Removes larger particles, sediments, and some microorganisms, serving as an effective initial filtration layer.
• Electrodeionization (EDI): Combines ion-exchange resins and an electrical current to continuously remove ions from water, producing high-purity water without chemicals—often used in pharmaceutical or semiconductor industries.

Uses porous materials like activated carbon to capture and remove dissolved organic compounds, chlorine, and taste/odor-causing substances. It’s highly effective for polishing water after other treatments, ensuring superior quality.

A versatile process that uses resins to swap ions in water with ions on the resin, allowing for the removal of unwanted ions. Different types of ion exchange resins are used for specific applications:

• Cation Exchange: Removes positively charged ions (cations) such as calcium (Ca²⁺), magnesium (Mg²⁺), and heavy metals. Commonly used for:
  • Softening: Replacing hardness-causing ions (calcium and magnesium) with sodium or potassium to prevent scale formation in pipes and equipment.
  • Removing specific cations like iron or lead from water.
• Anion Exchange: Removes negatively charged ions (anions) like nitrates (NO₃⁻), sulfates (SO₄²⁻), and chlorides (Cl⁻). Used for:
  • Targeting specific contaminants such as arsenic or fluoride.
  • Decarbonation or dealkalization to adjust water chemistry.
• Mixed Bed Ion Exchange: Combines cation and anion resins in a single unit to remove both types of ions simultaneously, producing highly purified water for specialized applications like laboratory or pharmaceutical use.

The most widely used method, where seawater is pressurized through a semi-permeable membrane, leaving salts and impurities behind. It’s energy-intensive but highly efficient, producing potable water with minimal chemical use.

Heats seawater to evaporate it, then condenses the vapor into fresh water, separating it from salts and minerals. Multi-stage flash distillation improves energy efficiency, making it viable for large-scale plants.

Employs an electric current to drive salt ions through selective membranes, concentrating them in separate streams while purifying the water. It’s particularly effective for brackish water with lower salinity.

Leverages solar energy to heat and evaporate seawater, followed by condensation, offering an eco-friendly, low-cost option for small-scale or remote applications.

A physical stage using screens to remove large debris and sedimentation tanks to settle heavy solids. It reduces solids by up to 60%, preparing water for further treatment.

Employs biological processes—activated sludge (microorganisms digest organic matter) or trickling filters (biofilms break down waste)—to remove dissolved organic content, reducing BOD significantly.

An advanced polishing step using sand filtration, chemical disinfection, or nutrient removal (e.g., phosphorus, nitrogen) to meet stringent reuse or discharge requirements, such as for irrigation or industrial cooling.

Handles the residual solids from treatment via anaerobic digestion (producing biogas), dewatering (reducing volume), or incineration, turning waste into a manageable or reusable byproduct.

Manages water in cooling systems to prevent scaling (mineral buildup), corrosion (metal degradation), and microbial growth (e.g., Legionella), using biocides, inhibitors, and regular monitoring.

Treats feedwater to eliminate scale (from calcium/magnesium deposits) and corrosion, while controlling dissolved oxygen and pH to extend boiler life and maintain steam purity for turbines or heating.

Customizes water quality for specific needs—e.g., deionized water for electronics, softened water for textiles, or sterile water for pharmaceuticals—ensuring product consistency and safety.

Processes effluents laden with chemicals, oils, or heavy metals using techniques like chemical precipitation, biological treatment, or membrane filtration to meet discharge limits or enable water recycling.

Integrates artificial intelligence to optimize dosing, predict equipment failures, and monitor water quality in real time, cutting costs and improving reliability across treatment plants.

Harnesses nanomaterials—like carbon nanotubes or graphene—for ultra-fine filtration, enhanced adsorption of pollutants, or catalytic breakdown of complex contaminants, outperforming traditional methods.

Pairs treatment systems with solar panels, wind turbines, or biogas from sludge to power operations, lowering energy bills and carbon emissions while supporting off-grid facilities.

Combines IoT sensors and data analytics to track water usage, detect leaks, and optimize distribution networks, ensuring sustainable supply and reducing waste in real time.