Pretreatment Sand Filtration System

Filtration Stage

Raw water enters from the water inlet at the upper part of the tank and flows downward through the filter media layer.

Pores between filter media particles intercept suspended solids and impurities in the water. Clean water flows out from the bottom water outlet to complete the filtration process.

 Backwashing Stage 

When impurities trapped in the filter media layer accumulate and cause the pressure difference between inlet and outlet water to exceed the set value (or reach the preset time), the system will automatically start backwashing.

The water flow direction is reversed, entering from the bottom and discharging from the top. Meanwhile, the multi-way valve controls

 Water Quality Parameters

Raw water turbidity: The higher the turbidity, the higher filtration precision filter media (such as fine-grain quartz sand) shall be selected, or additional pretreatment processes (such as flocculant dosing) shall be adopted.

 Type of impurities:

●Particulate impurities such as sediment and rust: Quartz sand filter media is preferred;

●Excessive iron and manganese ions: Manganese sand filter media is optional;

●High organic matter content: Activated carbon filtration or oxidation process shall be matched.

 Treatment Flow and Pressure

The conventional filtration flow velocity is 10 m/h; the upper limit can be adopted for large flow scenarios.

Working pressure: The pressure resistance of standard equipment is ≤1.0 MPa; customized pressure-resistant tanks are required for high-pressure working conditions.

 Automation Requirement

Control mode: Manual, semi-automatic or fully automatic (PLC + touch screen). The fully automatic type is suitable for unattended operation.

Backwashing trigger mode: Differential pressure control (recommended for higher accuracy) or time control.