The best thing about using slow sand water filtration is the fact that it utilizes biological processes in non-pressurized systems in order to produce clean, palatable water. There are no chemicals and no electricity used in the process, so it is very green. They are also very easy to construct. Slow sand filters have been used successfully in countries, such as in isolated areas of Afghanistan, where water quality is low. This can be the simplest, least expensive, and most efficient method of water treatment for many poor areas of the world.

Slow sand filters are typically employed to clean surface water. They do require a large space in which to operate. One or two yards deep is the amount of space usually required. The water run through these filters is stored inside of tanks until they’re needed. Modern cities such as London make use of these filters although they’re usually reserved for use by developing countries. Up to 12 sand beds can be filtering water at the same time with larger operations.

There are a series of herringbone drains covered by pebbles and coarse gravel in each bed. The bedrock is covered with layers of sand after with layers of fine sand are added. In fact, the majority of the sand filter is made up of fine sand. After everything is added, unfiltered water is added to the bed.

Within the first 10 days of operation, a gelatinous layer forms in the fine sand. This layer is made up of protozoa, fungi, rotifera, bacteria, and miscellanous larvae of aquatic insects. As the setup gets older, more organisms will start residing on the layer. This layer is responsible for making the water safe to drink again. This process is capable of removing up to 99% of the bacteria in the water.

The filtering layer needs to be overhauled occasionally in order to keep the water flowing. In some cases, the gelatinous layer is completely removed and then more water is introduced so that the layer will start forming again. This can take a long time Wet harrowing is a much quicker method however. This process washes away the contaminants until new water is added.

Slow sand filters aren’t used as much in the U.S. as they were in the past. Mainly this is due to the fact that they require so much land on which to operate, and as cities expand, they can no longer devote all of this land to water filtration. Slow sand filtration is, however, still one of the most effective ways on earth for the purification of water. Doc No.lsdhhsdlh-sdlkjhsgd

Kristie Brown writes on a variety of topics from health to technology. Check out her websites on Portable water purification system and Water filtration system