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Sand treatment plant

What is a sand treatment plant?

A sand treatment plant is a mechanism for filtering impurities that consists of a sand tank through which water circulates. The sand acts as a natural filtering agent, capturing any impurities in the water to purify it and ensure its quality.

How do sand treatment plants work?

Every sand treatment plant has a selector valve, a device that allows two pneumatic flows coming from two different pipes to flow into the same pipe without any interference. This filtration process through the valve carries the water to the filter, where impurities are removed and it is returned purified. 

At a sand treatment plant, this valve has 4 to 7 positions, with 6 being the most common. Each has its own function:

  1. Filter: This is the process of filtering water through water intakes or skimmers. This function lets the water that reaches the pump be pushed into the sand tank, where all the impurities are captured and deposited. 
  1. Backwash: every sand treatment plant has a pressure gauge, a component that measures the system’s pressure and ensures it is running properly. The pressure gauge should be washed regularly for sand maintenance. The most common indicator for backwash is that the water flow rate is lower.
  1. Rinse: after washing the sand, dirt must be removed from the bottom of the tank until the water comes out completely clean. 
  1. Recirculate: This option lets the water circulate without going through the sand tank. This procedure is usually done if, for example, the water has undergone a chemical treatment. 
  1. Waste: this involves totally emptying the water from the container. 
  1. Closed: this option is activated to cancel the water’s flow to the tank and the filter. 

In simpler terms, at the sand treatment plant, water with impurities is sucked through a tube, which acts as a collection system. Then, it passes through a filter where the sand is located and where impurities are filtered out and stored. 

What features are involved in a sand treatment plant?

For a sand treatment plant to fulfill its filtering function, the following elements must be installed: 

  • Water pump: responsible for moving the liquid to the filter and returning it once filtered and purified. 
  • Filters: for removing impurities.
  • Sump: located at the bottom of the container to absorb the water.
  • Skimmers: sucks and retains residues from the surface of the water for filtration and treatment. 
  • Nozzles: distributed throughout the container (pool) to expel the purified, disinfected water. 

What are the differences between sand and cartridge treatment plants? 

Unlike sand treatment plants, cartridge filters are lower-capacity filtration systems. Its filters must be replaced at least once a year, and maintenance for it involves removing and cleaning the cartridges periodically. Cartridge treatment plants cost less but are more limited in durability than sand treatment plants. The latter are more expensive, but they can last 7 to 10 years. 

Another big difference between these types of treatment plants is their capacity: the sand version can filter and clean large surfaces, while the cartridge version is more effective for small surfaces. 

Advantages and disadvantages of sand treatment plants

Considering the characteristics of sand treatment plants, some of its advantages would be:

  • It has a long use life.
  • They can be used on large and small surfaces because the filtration capacity can be chosen.
  • It is efficient and ecological to use silica sand as a natural filtering agent. Silica is insoluble in water and doesn’t generate polluting waste. 
  • They are very easy to maintain. 

While this is not really a disadvantage, the initial investment for a sand treatment plant is higher than other filtration systems. However, they tend to last longer, so there is a long-term cost reduction. 

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