- 2025-07-22
Green Sand Filter
The natural glauconite medium removes iron and manganese ions through oxidation reaction. After saturation, two regeneration methods can be used:
Continuous regeneration: chlorine is continuously added to the water inlet pipeline to ensure that the free chlorine concentration of the outlet water is maintained at 0.5-1ppm. When the test value exceeds this range, the water inlet flow rate needs to be adjusted synchronously to match the oxidation reaction rate.
Batch regeneration: Potassium permanganate (KMnO₄) cleaning is performed after the system is isolated. Taking a water source with an iron content of 1.0 GPG and a manganese content of 0.015 GPG as an example, at a filtration rate of 4 GPM/ft²:
TEXT
KMnO₄ demand = (1×Fe) + (2×Mn) = (1×1.0) + (2×0.015) = 0.13 GPG
Media load capacity: 1000 grains/square foot
Processed water volume: 1000 ÷ 0.13 ≈ 7692 gallons/square foot
Operation time: 7692 ÷ 4 = 1923 minutes (about 32 hours)
The corresponding backwash cycle is 30-36 hours.
System composition and operation specifications
The standard green sand filter includes a glass fiber reinforced plastic/steel tank, a valve control system (top/side mounted valve or PLC controller) and a medium layer (green sand + support layer). The system configuration follows the following principles:
Scale adaptation:
Small unit: equipped with Fleck®/Clack® mechanical valve
Medium unit: using pneumatic/electric diaphragm valve + digital display controller
Large unit: equipped with electric butterfly valve + PLC main control system
Operation parameters:
Optimum filtration rate: 2-5 GPM/ft²
Backwash intensity: ≥12 GPM/ft²
Medium filling volume: 50% of the tank volume (40% expansion rate during backwashing)
Engineering application scenarios
Direct filtration: Treat groundwater containing iron (≤15ppm), manganese (≤5ppm), and hydrogen sulfide (≤8ppm), and the output meets GB 5749 drinking water
Pretreatment system: Provide water supply guarantee for reverse osmosis device (control iron ions ≤ 0.05ppm, manganese/hydrogen sulfide approaching zero value)
Typical applications: industrial pure water preparation, municipal water supply quality improvement, commercial water quality upgrade
Technical advantage verification
Membrane system protection: Stable control of iron ions below the tolerance threshold of RO membrane (0.05ppm), extending membrane life by 3-5 times
Operation reliability: 1923 minutes of continuous operation cycle (previous working condition) reduces backwash frequency by 50%
Multi-scenario adaptation: single tank to multi-tank parallel architecture meets 2-500m³/h treatment needs
