A mathematical model is developed for biosparging with a horizontal slotted pipe. Biological processes are handled by means of Monod kinetics; biomass, oxygen, and substrate concentrations are assumed to be significant. The injected air is assumed to move through persistent channels in the aquifer. Distributed nonaqueous phase liquid may be present. The dependence of model results on some of the model parameters is explored. The sparging and biosparging of nonaqueous phase liquid volatile organic compounds of quite low water solubility (such as n-octane) are shown to be extremely slow. High dispersivities (perhaps the result of pulsed air injection) result in very markedly increased remediation rates.