Reverse Osmosis Filtration, Sand Filtration, Carbon Filtration, Precision Filtration, Fully Automatic Water Purification System

Product description

1. Sand Filtration (Pre-Filtration)

Purpose

• Removes physical contaminants (e.g., sand, silt, rust, suspended solids) from raw water.
• Acts as the first line of defense to protect downstream filters and membranes.

Mechanism

• Media Bed: Uses graded sand (or gravel) as a filter medium. As water passes through, particles are trapped via mechanical straining (blocked by sand gaps) and adsorption (sticky surfaces of sand grains capture smaller particles).
• Backwashing: Automatically triggered (via pressure sensors or timers) to reverse water flow, flushing out trapped debris and regenerating the filter bed.

Applications

• Pre-treating well water, surface water, or municipal water with high turbidity.
• Common in industrial, commercial, and residential systems (e.g., swimming pool filtration).

Specifications

• Media Size: 0.5–1.2 mm (coarse sand for high turbidity; fine sand for finer particles).
• Flow Rate: 5–20 m/h (dependent on media depth and tank size).
• Pressure Loss: 0.5–1 bar (replaced during backwashing).

2. Carbon Filtration (Pre/Post-Filtration)

Purpose

• Removes organic compounds (e.g., chlorine, pesticides, humic acids), odors, and color from water.
• Protects RO membranes from chlorine damage (chlorine degrades polyamide RO membranes).

Mechanism

• Activated Carbon Media: Porous structure with a high surface area (up to 1,500 m²/g) adsorbs contaminants via physical adsorption (van der Waals forces) and chemical adsorption (for polar molecules).
• Types of Carbon:
  • Granular Activated Carbon (GAC): Used for general dechlorination and organic removal.
  • Powdered Activated Carbon (PAC): Fine particles for high-efficiency adsorption (less common in automatic systems due to difficulty in backwashing).

Applications

• Pre-treatment before RO to protect membranes.
• Post-treatment in drinking water systems to enhance taste and odor.

Specifications

• Contact Time: 5–15 minutes (longer contact time improves adsorption efficiency).
• Backwashing: Similar to sand filters, using water or air to remove trapped organic matter.
• Media Lifespan: 6–12 months (depends on contaminant load; shorter in chlorinated water).

3. Precision Filtration (Pre-RO Filtration)

Purpose

• Removes fine particles (5–100 microns) that bypass sand and carbon filters, such as colloids, rust, and suspended solids.
• Protects the RO membrane from physical damage (e.g., scratches, clogging).

Mechanism

• Cartridge Filters: Disposable or cleanable filters with predefined pore sizes (e.g., 1, 5, or 20 microns).
• Types of Cartridges:
  • PP (Polypropylene) Spun Filters: Low-cost, high dirt-holding capacity for general particle removal.
  • Membrane Filters: Polyethersulfone (PES) or nylon membranes for precise particle retention.

Applications

• Critical pre-treatment for RO systems in industries like electronics, pharmaceuticals, and food processing.
• Ensures RO membrane feed water meets turbidity <1 NTU and SDI (Silting Density Index) <5.

Specifications

• Pore Size: Typically 1–5 microns for RO pre-treatment.
• Replacement Interval: 1–3 months (depending on water quality and flow rate).

4. Reverse Osmosis (RO) Filtration (Core Treatment)

Purpose

• Removes dissolved salts (e.g., NaCl, Ca²⁺, Mg²⁺), heavy metals, bacteria, viruses, and micron-scale contaminants (0.0001–0.001 microns).
• Produces low-salinity water (e.g., <50 ppm TDS for drinking water).

Mechanism

• Semipermeable Membrane: Allows water molecules to pass through but rejects ions and larger molecules via size exclusion and charge repulsion (for ionic contaminants).
• High-Pressure Pump: Generates pressure (5–10 bar for brackish water; 60–80 bar for seawater) to overcome osmotic pressure.
• Concentrate Rejection: Undesired contaminants are flushed out as concentrate (reject water), with a typical recovery rate of 70–90% (higher with energy recovery devices).

Applications

• Desalination of brackish water or seawater.
• Industrial water purification (e.g., boiler feedwater, pharmaceutical-grade water).
• Residential drinking water systems.

Specifications

• Membrane Type: Thin-film composite (TFC) polyamide for high rejection rates (>99% for salts).
• Lifespan: 3–5 years with proper pre-treatment and maintenance.

5. Fully Automatic Control System

Key Features

• PLC/Touchscreen Interface: Manages all processes (filtration, backwashing, RO flushing, tank level control) via programmable logic.
• Sensors:
  • Pressure Sensors: Monitor inlet/outlet pressure to trigger backwashing or filter replacement.
  • Conductivity/TDS Meters: Measure water purity and adjust RO operation (e.g., flush when TDS exceeds set limits).
  • Flow Meters: Track water usage and detect leaks.
• Automatic Backwashing/Flushing:
  • Sand/Carbon Filters: Backwashed with water (and air for carbon) to remove debris.
  • RO Membrane: Flushed with permeate water post-operation to prevent salt buildup.
• Fault Alarms: Notifies operators of issues (e.g., low pressure, high TDS, pump failure).

How They Work Together: System Flowchart

Raw Water → Sand Filter (removes large particles) → Carbon Filter (removes organics/chlorine) → Precision Filter (removes fine particles) → RO Membrane (removes dissolved salts) → Treated Water Tank  
                                                                          ↓  
                                                               Concentrate (discharged/recycled)  

Applications of the Fully Automatic System

1. Drinking Water Production: Combines all filters for safe, low-salinity tap water.
2. Industrial Processes: High-purity water for electronics (e.g., semiconductor cleaning), power plants (boiler feedwater), and cosmetics.
3. Marine Desalination: Converts seawater to potable water on ships/yachts.
4. Agriculture/Irrigation: Reduces salinity and hardness to protect crops and irrigation systems.

Advantages of an Integrated System

1. Comprehensive Contaminant Removal: Addresses physical, organic, and ionic contaminants.
2. Low Labor Cost: Fully automated operation reduces manual intervention.
3. Consistent Water Quality: Real-time monitoring ensures stable output.
4. Longevity: Proper pre-treatment extends RO membrane life and reduces maintenance.

Maintenance Tips

• Sand/Carbon Filters: Backwash regularly (weekly/monthly) and replace media every 1–2 years.
• Precision Filters: Replace cartridges every 1–3 months.
• RO Membranes: Perform chemical cleaning (e.g., with citric acid or sodium hydroxide) every 6–12 months to remove biofouling/scaling.
• Sensors/Valves: Calibrate annually and inspect for leaks or blockages.