In-situ bioremediation is a viable option for denitrification of Chalk groundwaters

Nitrate potentially has a major impact on the quality of groundwater for po table supply. Conventional treatment methods to control nitrate problems in abstracted groundwater are expensive, in terms of unit costs and environme ntal impact. utilizing the natural denitrifying capacity of aquifers offers an alternative approach to nitrate management based on in-situ bioremediat ion, which may have a number of strategic advantages including financial be nefits and environmental sustainability, This paper reviews a range of lite rature from different scientific disciplines, regarding the physical and bi ological factors controlling denitrification in fissured aquifers, to asses s whether in-situ bioremediation of nitrate in Chalk groundwaters is techni cally feasible. The principal conclusion is that, despite the dual-porosity operating in this type of aquifer, nitrate removal by engineered, in-situ bioremediation is potentially a viable and practicable method for treating groundwater. Process optimization could be achieved by investment in a prog ramme of fundamental research in a number of key areas. The review highligh ts the need for a combined experimental and modelling approach, to satisfy the data and predictive requirements for configuring in-situ bioremediation systems at the field-scale. It also provides the necessary conceptual basi s for developing a combined macroscale hydrogeological and biochemical mode l of denitrification activity in Chalk aquifers.