Bioclogging or biological clogging is clogging of

pore space in soil The pore space of soil contains the liquid and gas phases of soil, i.e., everything but the solid phase that contains mainly minerals of varying sizes as well as organic compounds. In order to understand porosity better a series of equations have ...

by microbial biomass; their body and their byproducts such as

extracellular polymeric substance Extracellular polymeric substances (EPSs) are natural polymers of high molecular weight secreted by microorganisms into their environment. EPSs establish the functional and structural integrity of biofilms, and are considered the fundamental comp ...

(EPS). The microbial biomass blocks the pathway of water in the pore space, forming a certain thickness of impermeable layer in soil, and it reduces the rate of

infiltration Infiltration may refer to: Science, medicine, and engineering *Infiltration (hydrology), downward movement of water into soil *Infiltration (HVAC), a heating, ventilation, and air conditioning term for air leakage into buildings *Infiltration (me ...

of water remarkably. Bioclogging is observed under continuous ponded infiltration at various field conditions such as artificial recharge ponds,

percolation trench A percolation trench, also called an infiltration trench, is a type of best management practice (BMP) that is used to manage stormwater runoff, prevent flooding and downstream erosion, and improve water quality in an adjacent river, stream, lake ...

irrigation Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...

channel,

sewage treatment Sewage treatment (or domestic wastewater treatment, municipal wastewater treatment) is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable for discharge to the surrounding envir ...

system and

landfill liner A landfill liner, or composite liner, is intended to be a low permeable barrier, which is laid down under engineered landfill sites. Until it deteriorates, the liner retards migration of leachate, and its toxic constituents, into underlying aqu ...

. It also affects groundwater flow in

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characterist ...

, such as

permeable reactive barrier A permeable reactive barrier (PRB), also referred to as a permeable reactive treatment zone (PRTZ), is a developing technology that has been recognized as being a cost-effective technology for ''in situ'' (at the site) groundwater remediation. PRBs ...

and

microbial enhanced oil recovery Microbial enhanced oil recovery (MEOR) is a biological based technology consisting in manipulating function or structure, or both, of microbial environments existing in Petroleum reservoir, oil reservoirs. The ultimate aim of MEOR is to improve the ...

. In the situation where infiltration of water at appropriate rate is needed, bioclogging can be problematic and countermeasures such as regular drying of the system are taken. In some cases bioclogging can be utilized to make impermeable layer to minimize the rate of infiltration.

General description

Change in permeability with time

Bioclogging is observed as the decrease of the infiltration rate. Decrease in the infiltration rate under ponded infiltration was observed in 1940s for studying the infiltration of artificial recharge pond and the water-spreading on agricultural soils. When soils are continuously submerged, permeability or saturated

hydraulic conductivity Hydraulic conductivity, symbolically represented as (unit: m/s), is a property of porous materials, soils and rocks, that describes the ease with which a fluid (usually water) can move through the pore space, or fractures network. It depends on th ...

changes in 3 stages which was explained as follows. # Permeability decreases for 10 to 20 days possibly due to physical changes of the structure of the soil. # Permeability increases due to dissolving the entrapped air in soil into the percolating water. # Permeability decreases for 2 to 4 weeks due to disintegration of aggregates and biological clogging of soil pores with microbial cells and their synthesized products, slimes or polysaccharides. The 3 stages are not necessarily distinct in every field condition of bioclogging; when the second stage is not clear, permeability just continues to decrease.

Various types of clogging

The change in permeability with time is observed in various field situations. Depending on the field condition, there are various causes for the change in the

, summarized as follows. # Physical causes: Physical clogging by

suspended solids Suspended solids refers to small solid particles which remain in suspension in water as a colloid or due to motion of the water. Suspended solids can be removed by sedimentation if their size or density is comparatively large, or by filtration. It ...

or physical changes of soils such as disintegration of aggregate structure. Dissolving of the entrapped air in soil into the percolating water is physical cause for the increase of the hydraulic conductivity. # Chemical causes: Change in the

electrolyte An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon dis ...

concentration or the

sodium adsorption ratio The Sodium adsorption ratio (SAR) is an irrigation water quality parameter used in the management of sodium-affected soils. It is an indicator of the suitability of water for use in agricultural irrigation, as determined from the concentrations of t ...

in the aqueous phase, which causes

dispersion Dispersion may refer to: Economics and finance * Dispersion (finance), a measure for the statistical distribution of portfolio returns * Price dispersion, a variation in prices across sellers of the same item *Wage dispersion, the amount of variat ...

and swelling of clay particles. # Biological causes: Usually bioclogging means the first of the following, while bioclogging in broader sense means all of the following. ## Bioclogging by microbial cell bodies (such as

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

and

fungus A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from th ...

) and their synthesized byproducts such as

(EPS) (also referred to as slime), which form

biofilm A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular ...

microcolony {{Short pages monitor