Perkolasjon

Perkolasjon, or percolation, is the process by which a liquid moves downward through a porous medium under the influence of gravity and pressure differences, driven by capillary forces in the pore spaces. In soil science and hydrology, perkolasjon describes how water infiltrates soil, drains, and moves through the subsurface. The rate and pattern of perkolation depend on soil properties such as porosity, permeability, and pore-size distribution, as well as moisture content and temperature. In many models the flow is described by Darcy's law, which relates discharge to hydraulic conductivity and gradient; in practice, percolation through soils can be slowed by low permeability, soil layering, or macropores that channel flow.

Perkolasjon has important practical implications. It governs groundwater recharge, the leaching of nutrients and contaminants, drainage design for agriculture and construction, and the operation of filtration systems and wastewater-treatment media. In Norwegian contexts, perkolasjonstest is used to evaluate soil drainage capacity for septic systems and drainage fields, guiding the sizing of infiltration beds and leachate management.

In culinary uses, perkolasjon also refers to a coffee brewing method in which water is repeatedly forced through coffee grounds by a percolator. The process exposes grounds to hot water through multiple cycles, producing a strong, robust brew, though flavor can vary with design and technique.

Overall, perkolasjon describes the movement of liquids through porous media across disciplines, from natural hydrology to engineered filtration and even culinary applications.