A screen arc model well to simulate iron bacterial fouling

Abstract

A laboratory modelling system is described within which the activities associated with the microbiological fouling (plugging) of a well can be stimulated at much higher rates than are experiented in the field. The method employs a miniaturised quadrant of a well established within a defined chemostat system in which a nutrient enriched water is flowed through a gravel pack to a slotted stainless steel arc of well screen material into a discharge cistern where either drainage or over-spillage can be used to partially control flow. Oxygen conditions may be manipulated by either the introduction of continues or sequential pulses of air or oxygen exclusion through a nitrogen sparging the enclosed system. Monitoring is undertaken by determining the drainable volume of water from the well which declines as the biofilm volume increases and intercedes flow and also by measuring the drainage time which increases as a resistance to flow is generated by the biofilm growth. A process of self-purification of a model well subjected to total plugging with a consortial iron bacterial growth is described by way of an illustration of the usefulness of the procedure.