Sandfilter

Sand filters, other synonyms for gravel filters used in water technology, are filters that work with sand as a filter medium. They are used in several areas.

Hunting and

The sand filter is a special aquarium filter inside the aquarium. He is one of the external filters.

The sand filter is a multi- sectioned extra tank in which the water flows through different filter wool and sand layers. The extra tank is located below the actual aquarium tank. The water passes through an overflow in this extra pool that is usually located in the lower cabinet. In the last chamber contains an electric submersible pump, which conveys the water back into the pool.

The sand filter is suitable for both freshwater and marine aquariums.

Protection space technology

A sand filter is used in many protective structures. It is an important component of the protective ventilation system, which is responsible for the care of the shelter occupants with clean, fight -free air. It consists in principle of one or more concrete or steel tanks which are filled with sand. The way it works is simple: The fresh air flows through the suction device ( s) in the sand filter chamber and is then pulled through the sand. Here, three things happen:

1 The air is freed of ( radioactive ) particles and biological or chemical warfare agents.

2 If the air temperature is increased, for example by fires outside the shelter, the sand absorbs the heat so that the shelter can continue to prevail tolerable temperatures.

3 A possibly penetrating blast wave is attenuated, if it has not already been stopped by the upstream in some shelters surge- protection valves.

There are two types, the Sandvorfilter and the sandy main filter. The main sand filter is used on its own and to ensure a complete filtering of the fresh air, while the Sandvorfilter is always used in conjunction with spatial filters and the air is to filter out only to protect the air filter from premature clogging or burning. The sandy main filter differs technically only by the finer filter material and the resulting better filter effect from Sandvorfilter.

Waste water treatment

A sand filter is usually applied in a wastewater treatment plant as a final purification step. He serves as a first for the filtration of suspended particles in the wastewater but also for downstream denitrification by addition of easily degradable organic compounds.

Filtration of suspended particles in the wastewater.

The waste water is removed by this method to 99% of solids.

Sand filters are used in rural areas and for purification of domestic wastewater. In areas outside the catchment areas, drains the effluent shall be cleaned with a small sewage treatment plant. Following a septic tank ( mechanical cleaning) prepurified sewage is intermittently sprayed on a sand filter. When leakage through the filter, the water is biologically cleaned and can be released back into the environment in clean condition. In the gradient function sand filter wastewater treatment plants without electricity.

Other uses of the term

In aeronautics special filters before the air intakes of turbines are referred to as sand filters or foreign body trap. These structures hold the sand and other small parts away from the turbines and thus increase the life and reliability of drives strong. They are mostly used in helicopters, flying in desert regions or frequently over unpaved ground.