Bioclogging or biological clogging refers to the blockage of pore space in soil by microbial biomass, including active cells and their byproducts such as extracellular polymeric substance (EPS). The microbial biomass obstructs pore spaces, creating an impermeable layer in the soil and significantly reducing water infiltration rates.
Bioclogging occurs under continuous ponded infiltration at various field conditions such as artificial recharge ponds, percolation trenches, irrigation channels, sewage treatment systems, constructed wetlands, landfill liners and natural systems such as riverbeds and soils. It also affects groundwater flow in the aquifer, such as ground source heat pumps, permeable reactive barriers, and microbial enhanced oil recovery. Bioclogging is a significant problem where water infiltration is hampered and countermeasures such as regular drying of the system can reduce the levels of bioclogging. However, bioclogging can also serve beneficial purposes in specific conditions. For instance, bioclogging can be utilized to make an impermeable layer to minimize the rate of infiltration or to enhance soil mechanic properties.
Bioclogging is observed as the decrease in the infiltration rate. A decrease in the infiltration rate under ponded infiltration was observed in the 1940s for studying the infiltration of artificial recharge ponds and the water-spreading on agricultural soils. Allison described [1] that when soils are continuously submerged, permeability or saturated hydraulic conductivity changes in 3 key stages:
This description is based on experiments conducted at that time, and the actual process of bioclogging depends on system conditions, such as nutrient and electron acceptor availability, microbial biofilm formation propensity, initial conditions, etc. In particular, the 3 stages are not necessarily distinct in every field condition of bioclogging; when the second stage is not clear, and permeability just continues to decrease.
The change in permeability with time is dependent on the field condition and there are various causes for the change in the hydraulic conductivity, [2] including physical (suspended solids, disintegration of aggregate structure, etc), chemical (dispersion and swelling of clay particles), and biological causes (as listed below). Usually bioclogging means the first of the following, while bioclogging in a broader sense means all of the following.
Bioclogging is mostly observed in saturated conditions, but bioclogging in unsaturated conditions is also studied. [17]
Bioclogging is a significant issue in various environmental and artificial water systems. Here are some specific field problems related to bioclogging and their potential countermeasures.
In certain environments, bioclogging positively influences hydrological process. Here are some examples.
This article was submitted to WikiJournal of Science for external academic peer review in 2023 ( reviewer reports ). The updated content was reintegrated into the Wikipedia page under a CC-BY-SA-3.0 license ( 2024 ). The version of record as reviewed is: Katsutoshi Seki; et al. (14 February 2024). "Bioclogging" (PDF). WikiJournal of Science. 7 (1): 1. doi: 10.15347/WJS/2024.002 . ISSN 2470-6345. Wikidata Q116782181.