sealing mechanism of wastewater ponds

Columns packed with sand, sandy soil, loamy soil, and silty clay were planted at the bottom of a newly-constructed dairy wastewater pond to determine the reduction of the infiltration rate and the chemical changes of soils. Hydraulic conductivities of subsequently recovered columns indicated a significant reduction of infiltration rate. Ponds can be sealed off within 2 months after operation. The sealing was attributed to the physical entrapment of organic particulates in the soil pores followed by the growth of slime-forming microorganisms. The chemical changes of soil did not play any significant role in the process. This seal was not permanent and can be broken by drying.