PREDICTING THE CLOGGING RATE OF ARTIFICIAL RECHARGE WELLS

When infiltrating pretreated surface water in the soil with recharge w ells, one may be confronted with clogging of these wells, caused by de position of particles and by bacterial growth, In practice, it is diff icult to predict the clogging rate of these recharge wells. The Modifi ed Fouling Index, measured with membrane filters with 0.45 mu m pores (MFI (0.45)), and the assimilable organic carbon content (AOC) are, in practice, valuable parameters with regard to the clogging potential o f the water to be infiltrated. However, for a reliable prediction of t he clogging rate of recharge wells, these parameters prove to be inade quate. The measurement of clogging potential as a result of particle d eposition together with bacterial growth, forms an essential supplemen t to the MFI (0.45) and the AOC content, The method applied for this m easurement makes use of experimental filters in which the simulated cl ogging process occurs in an accelerated way. In principle it is possib le to predict the clogging rate of the recharge wells on the basis of the measured clogging potential. For this, the composition of the soil must be established precisely. Furthermore, if no disinfectant is add ed, the AOC content should show no significant variations.