Sand Filter,Carbon Filter,Softener Belt Primary Reverse Osmosis With Precision Filter Purification Water Treatment Equipment

Product description

1. Sand Filter
Function and principle
Core function: Through the interception effect of filter media such as quartz sand, large particle impurities such as suspended solids, sediment, rust, colloids, etc. in raw water are removed, and the turbidity of water is reduced (usually from tens of NTU to below 5NTU).
Workflow:
Filtration stage: Raw water enters the sand filter from the top and passes through the filter layer from top to bottom, with impurities trapped on the surface and pores of the filter material.
Backwash stage: When the resistance of the filter layer increases (such as when the pressure difference reaches the set value), automatic backwashing is initiated, and the water flow reverses to flush the filter material, remove trapped impurities, and restore filtration capacity.
Key parameters: The particle size of the filter material is generally 0.5-1.2mm, the filtration flow rate is 5-10m/h, and the backwash strength is 15-20L/(m ² · s).
2. Carbon Filter
Function and principle
Core function: Utilizing the adsorption properties of activated carbon, it removes residual chlorine, organic matter (such as pesticides and humic acid), pigments, odors, and some heavy metals (such as lead and mercury) from water, protecting subsequent reverse osmosis membranes from oxidative damage.
working principle:
Activated carbon has a huge specific surface area (500-1500m ²/g) and microporous structure, which captures pollutants through physical adsorption (van der Waals force) and chemical adsorption (surface functional group reaction).
The adsorption of residual chlorine belongs to a chemical reduction reaction (such as activated carbon reducing Cl ₂ to Cl ⁻).
Maintenance points: After saturation of activated carbon adsorption, it needs to be replaced regularly (usually 1-2 times a year), or its performance can be restored through regeneration treatment.
3. Softener Belt
Function and principle
Core function: Remove calcium (Ca ² ⁺) and magnesium (Mg ² ⁺) ions from water through ion exchange resin, reduce water hardness (such as reducing hardness from 100mg/L to below 5mg/L), and prevent reverse osmosis membrane fouling (such as precipitation of calcium carbonate and calcium sulfate).
working principle:
In the resin filled tank, Na ⁺ on the resin undergoes an exchange reaction with Ca ² ⁺ and Mg ² ⁺ in the water:
2R Na+Ca ² ⁺ → R ₂ – Ca+2Na ⁺ (R represents resin group).
Regeneration stage: Rinse the resin with sodium chloride (NaCl) solution to replace Ca ² ⁺ and Mg ² ⁺ and remove them, restoring the resin’s exchange capacity.
Type: divided into manual regeneration and fully automatic regeneration (such as regeneration cycle controlled by PLC).

4. Primary Reverse Osmosis (RO)
Function and principle
Core function: Utilizing the selective permeability of semi permeable membranes, dissolved salts (such as NaCl), bacteria, viruses, small molecule organic matter, etc. in water are intercepted under high pressure (0.8-1.5MPa), producing low salt purified water (desalination rate usually reaches 95% -98%).
System composition:
High pressure pump: provides the pressure required for membrane separation, and the power is designed according to the water production rate (for example, a pump power of about 3-5 kW is required for a water production rate of 1 m ³/h).
Reverse osmosis membrane: commonly used roll type membranes (such as Dow FilmTec, Heidelberg), with membrane element diameters of 4-8 inches and lengths of 36-60 inches.
Concentrated water discharge: About 15% -25% of the raw water is discharged as concentrated water to remove trapped impurities, which can improve water utilization efficiency through a concentrated water recovery system.
Key indicators: influent SDI (pollution index) ≤ 5, residual chlorine ≤ 0.1mg/L, water temperature 15-35 ℃.
5. Precision Filter
Function and principle
Core function: Also known as a security filter, it is installed in front of the reverse osmosis membrane with a filtration accuracy of usually 5 μ m. It intercepts small particles, colloids, and suspended solids remaining after sand filtration/carbon filtration, and protects the reverse osmosis membrane from physical damage (such as scratching the membrane surface).
Structural features:
Cylindrical filter shell, filled with PP melt blown filter element or wire wound filter element, the replacement cycle of the filter element depends on the water quality (usually 1-3 months).
When the filtration flow rate is 1-3m ³/(m ² · h) and the pressure difference exceeds 0.1MPa, the filter element needs to be replaced.
Equipment linkage process and application scenarios
1. Processing flow
plaintext
Raw water → sand filter (to remove large particles) → carbon filter (to remove residual chlorine and organic matter) → softening device (to remove calcium and magnesium ions) → precision filter (to remove fine particles) → primary reverse osmosis (deep desalination) → purified water
2. Application scenarios
Industrial production: electronics industry (chip cleaning water, resistivity ≥ 15M Ω· cm), chemical industry (desalination of process water).
Drinking water treatment: community direct drinking water system, school/hospital water purification equipment (effluent meets GB5749 standard).
Food and beverage: Pre treatment of water sources in beer and purified water production to ensure taste and process requirements.
Boiler water: Reduce hardness, prevent boiler scaling, and ensure safe operation of equipment.
Equipment advantages and maintenance points
advantage
Multi stage filtration collaboration: gradually removing impurities from large particles to ion level, ensuring stable effluent quality.
Automation control: PLC system can be configured to achieve fully automatic operation of sand filter/carbon filter backwashing, softening regeneration, reverse osmosis start stop, etc., reducing labor costs.
High cost-effectiveness: Compared to two-stage reverse osmosis, the cost of first stage RO combined with pretreatment equipment is lower, making it suitable for medium desalination demand scenarios.

Maintenance points
Regularly monitor the inlet and outlet pressure difference of sand filter/carbon filter, and promptly backwash or replace the filter material.
The regeneration frequency of softened resin is adjusted according to the hardness of the raw water (such as shortening the regeneration cycle when the hardness is high).
Regular chemical cleaning of reverse osmosis membranes (such as using citric acid solution to remove carbonate scale and sodium hydroxide solution to remove organic pollution) can extend membrane life (usually 3-5 years).
This combination device achieves efficient removal of impurities in water through a multi-stage filtration mode of “pretreatment+desalination”, especially suitable for scenarios with high hardness and high organic content in raw water. It is one of the mainstream solutions in the industrial and civilian water purification fields.