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Drainfield
Storyboard 
A drainage field is an essential part of a septic system, designed to treat and disperse treated wastewater coming from a septic tank. Its operation is based on the natural filtration of water through the soil and biological processes that remove contaminants before they reach groundwater or surface water.
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Drain field working principle
Description
The drainage field consists of a network of perforated pipes buried in trenches filled with gravel or sand. Wastewater, previously separated from solids and grease in the septic tank, flows into these pipes. From there, it is evenly distributed to the gravel or sand bed, which acts as a filtering medium.
The soil beneath the field plays a crucial role: natural bacteria present decompose organic matter, eliminate pathogens, and absorb nutrients like nitrogen and phosphorus. This process ensures that the water eventually infiltrating the subsoil is significantly purified.
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Creating access to the drainage field
Description
Since the drainage field will be located in the lower part of the terrain and the excavator needs to operate in that area, a pathway must be created to allow the equipment to descend:
Excavator descending
As the excavator progresses, it carves out the access path:
Building the path
Finally, the equipment reaches the lower area:
Pathway completed to the lower zone
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Creation of the drainage field
Description
A trench is excavated measuring approximately 8 meters long, 1 meter wide, and 1.5 meters deep:
Excavating the trench
It is then filled with large stones (bolones) and covered with a plastic sheet to prevent additional water infiltration from the surface:
Covering the drainage field
This system filters the wastewater separated from the sludge by the septic tank, allowing it to be absorbed into the soil.
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Completion of construction
Description
The drainage field is finalized by covering it, while an inspection and distribution chamber is installed at one end. This ensures that the water from the septic tank is properly distributed into the drainage field:
Completed drainage field
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