What is Shallow Sand Filters?
Shallow sand filter is a physical filtration device used for water treatment. It mainly intercepts suspended matter, colloids, microorganisms and other impurities in the water through the sand layer to improve the water quality. The following is a detailed description of its key features and working principles.
1. Structure and composition.
- Tank: Usually made of corrosion-resistant materials, mostly cylindrical or square in shape.
- Filter layer: Use quartz sand of different particle sizes, such as fine sand on the upper layer and coarse yarn on the lower layer, to form a multi-layer filtration structure to enhance the ability to intercept pollutants.
- Water distribution system: Evenly distribute the incoming water to avoid disturbance of the sand layer caused by water flow impact.
- Water collection system: Located at the bottom, collects the filtered clean water, usually designed as a porous plate or filter head structure.
- Backwash device: Used to regularly clean up the intercepted impurities and restore the filtration capacity of the sand layer.
2. Working principle.
- Filtration stage: The raw water flows through the sand layer from top to bottom, and the particles are intercepted step by step by the sand layers of different particle sizes. The fine sand layer is responsible for intercepting tiny particles, and the coarse sand layer prevents blockage and extends the filtration cycle.
- Backwashing stage: The sand layer is expanded by reverse water flow to wash away the sediment, and the backwash water is discharged into the wastewater system. Some designs use automatic control to trigger flushing according to pressure difference or time.
3. Selection considerations.
- Water quality analysis: The turbidity and pollutant type of the inlet water must be clearly defined.
- Flow matching: Design according to the peak flow, and reserve 20% margin to cope with sudden loads.
- Material selection: 316L stainless steel is recommended for acidic water, and thermal deformation factors must be considered in high temperature environments.
Shallow sand filters have become the preferred solution in the fields of reclaimed water reuse and industrial water treatment due to their reliability and economy, especially for projects that require continuous operation and are sensitive to land occupation. In actual applications, customized design needs to be combined with water quality reports.
Any requirements, contact us now!
Nina
Email: nina@filtrationchina.com
Mobile/Whatsapp/WeChat：+86 172 6957 1060
