One method for purifying water is sand filtration. This process uses the porous properties of sand to retain specific substances. Combining this method with others, such as activated carbon, is common when performing filtration. As its name suggests, sand water filters are just that: filters that use sand as their media.
Sand water filters comprise sand of varying sizes, with a porous double bottom (collector) at the filter’s base. Depending on the liquid flow rate, sand water filters can be small or very large. A filter made of concrete, plastic, or steel usually contains sand.
What is the process of sand filtration?
Sand filters use sand with a certain particle size to filter water as it runs horizontally through a bed of sand. It is common practice to use many layers of sand of varying particle sizes to filter out different types of floating debris from water. A porous layer in the sand bed guarantees the filter’s functionality. Additionally, sand water filters can undergo a number of biological and physical processes. This leads to the removal of even more components.
The sand filter’s upper layer will collect the removed particles, and after some time, further pressure will help force the water through the filter. After some time, you can reuse a sand water filter by backwashing it. This removes any remaining particles and keeps the filter from clogging. The water’s flow direction is reversed to accomplish this backwashing.
What are the advantages of sand water filters?
- The most durable materials are glass and sand.
- It is possible to remove ammonia, demagnification, and deferrisation.
- Efficient removal and extended lifespan.
- Decrease of bacteria and protozoa.
- Simple to operate and easy to use.
- Minimal maintenance is needed, and it is easy to run.
- It is possible to eliminate various floating particles.
What are the drawbacks of a sand filter?
- Invisible, microscopic particles suspended in water
- One way to reduce water waste in a pool is to backwash it.
- Not very good at preventing the spread of viruses.
- The filters’ height and weight make transportation a challenge.
- Sand needs replacement every five years.
- The possibility of filter clogging is a significant drawback of slow sand filtration.
- It will cost extra to treat and dispose of the water.
What can sand filtration remove?
Sand filtration removes manganese particles, seeds, sludge, solids, precipitated iron, and insects. It can also reduce the population of bacteria and protozoa through biological and physical processes within the filter. Things like drinking water, process water, wastewater, surface water, pool water, and cooling water have this taken out of them.
The three types of sand filters?
A sand water filter is a typical choice when purifying water. Particularly in places lacking centralized sewage systems, their low cost and ease of operation make them popular.
Rapid Sand Filters
Municipal drinking water facilities often use these systems as a multi-stage treatment system. In order to remove contaminants from water that have become trapped in a flocculation due to flocculation chemicals, they use a granular medium such as moderately coarse sand. With the flocculated materials contained as the water flows through the sand matrix, the emerging water is clean and safe to drink.
After forcing compressed air up through the bottom of the filter, you can clean the rapid sand filter by flowing water upwards through it. This air-blowing operation breaks up the compact media filter.
Advantages:
- They are reusable and may be cleaned by flushing them back.
- Removes almost all particles that exceed the specified pore sizes.
- Because of their relative strength, they are able to endure pressure differentials of 2 to 5 atmospheres.
- Their incredibly thin profile allows liquids to pass through them at high speeds.
- Unlike sand and paper filters, parts as fine as 0.3 µm are captured.
Slow sand filters
Most of these filters are slow-sand types. Sand filtration uses the natural filtration properties of sand to create potable water. People in isolated and economically challenged places have the best option for water purification with this procedure. This is because it requires minimal operator training, chemicals, mechanical power, replaceable components, and periodic maintenance.
Space and land are abundant in areas where slow sand filters can be used. This allows water to be passed through at a leisurely pace. Rather than relying on physical processes to purify water, these sand filters employ biological processes. They are not pressure-sensitive devices.
Upward flow sand filters
These filters collect sand from the ground. Unlike traditional filtration methods, which involve pushing water downward through layers of gravel and sand, these sand water filters use an upward motion to move water. Gravel and sand act as filters, drawing out pollutants from the water as it flows through them.
Applications of Sand Filtration
For its low price and wide availability, sand is a great filtration medium for removing suspended solids, improving water’s smell, taste, and color, and even killing 99 percent of germs.
- Iron removal
- Wastewater treatment
- Filtration of the surface or water
- Membrane systems’ pre-filtration
- Drinking water production
- Cooling water preparation
Sand selection is always a must! In addition to having specific qualities, the chosen medium must be washed at an appropriate processing facility. Depending on the system in question, these features could vary slightly, but they always encompass:
Hardness
It is best to use hard, dense, and resistant particles with a high silica concentration. Otherwise, they will be more prone to erosion.
Sand can be utilized alone in water filtration systems or as part of a multi-media system (in conjunction with flocculants and other filtration materials like charcoal) for enhanced efficiency.
Shape
The ideal grain form is somewhere between sub-angular and sub-rounded. Too-smooth grain increases the likelihood that it will dissolve and shorten the filter’s life. Cleaning (back-washing) might cause flat grains to become lost.
Effective Size
Particles won’t be able to be caught if the sand is too big, and they’ll build up on the filter bed’s surface if it’s too tiny, blocking the passage of fluid.
Conclusion
Sand embodies both traditional knowledge and contemporary efficiency in water filtering. Its natural filtering properties, affordability, and adaptability make it an essential part of water treatment systems all around the globe. To get in touch with the ideal industrial filtration system that suits your needs, contact Express Drainage Solutions immediately. Your team can improve performance and save money with our extensive filtering options.