Sand Filtration

Overview

The sand filter is an environmentally-friendly wastewater and ground water treatment method, which is relatively simple and inexpensive. Its principle involves percolating water through a sand bed. It is a process in which the treatment of the water is done by the ‘porous’ nature of the sand layer which traps particles present in water. Grains of sand form a layer which is penetrated by the water and which will stop larger particles in the intervals between grains acting like a simple sieve. Smaller particles will also be retained by the wall effect on the grain surface when they touch a grain as they pass through the filter. The smaller the diameters of the grains, the longer the particles remain in the filter, the higher the filter’s stopping power is.

Various other physical/ biological processes also take place in a sand filter which further strip the water of different substances (deferrisation, demanganisation, ammonium removal). It is also used to remove dissolved iron. Iron and manganese in groundwater are oxidised by aeration and the flocs formed are subsequently trapped in the sand filter. After a certain period of time, the filter is saturated with particles and must be cleaned to prevent it from blocking up completely. Sand filters are cleaned by backwashing with air and/or water.

Waterman supplies four types of sand filtration, depending on the requirements of the treatment plant and the quantity of water needing filtering :

• rapid (gravity) sand filters
• rapid (pressure) sand bed filters
• upflow sand filters
• slow sand filters

Waterman’s complete range of modular and flexible skid-mounted sand filters and multimedia filters, allows for the whole range of requirements, from municipal application to industrial application:

• Drinking water treatment
• Process water production
• Treated water reuse

Our expert team is always ready to help what ever your need, no matter how big or how small. Contact Waterman Eswatini today.