ABSTRACT
For the production of drinking water, Waterleiding Maatschappij Limburg (WML) will be using more surface water in order to save groundwater. Natural processes have been chosen to give the surface water the character of groundwater by means of recharge. In Heel, water from the river Maas is used, the water being pumped to a reservoir with a volume of 25 million m3. The reservoir ‘De Lange Vlieter’ is the result of gravel extraction from an area 1 km distant from the river Maas. In recent years, different studies have been made of the feasibility and design of the project. As from 2002, 20 million m3 of bank-filtered water will be recovered annually. The reservoir itself will be continuously supplemented by river water. The bank-filtered water will be recovered divided over three well-fields, with in total approximately 30 wells. The design of the wellfields will be such that water in the subsoil will have a residence time of at least 30 days, resulting in pumped water being free of pathogenic micro-organisms. It is judged that disinfection of the pumped water is therefore not necessary. For the design of the posttreatment process for this water, a rapid decrease in its iron concentration is expected. The manganese concentration will also drop, although less rapidly.
