Submersible sampling pump proves indispensable when measuring water quality in the Netherlands

Under the Water Framework Directive (WFD), there is a legal obligation to guarantee the quality of groundwater. With this legislation in mind, a groundwater quality monitoring network consisting of some 70 to 80 locations throughout the Dutch province of Limburg has been set up. Samples are taken annually at these locations and on the advice of Eijkelkamp Soil & Water, Grundfos MP 1 submersible pumps are used. These Grundfos submersible pumps are ideal for pumping and sampling monitoring wells with a diameter of 55 mm or more.

The MP1’s pump motor is controlled by a special, adjustable frequency converter. Since the frequency is continuously adjustable, the capacity of the MP1 pump can be controlled from 0 to 2 m3/hour, which allows water to be pumped through the monitoring well quickly. A lower frequency is set for sampling the monitoring wells.'

In addition to the groundwater quality monitoring network, the Grundfos MP 1 pumps are also utilised for the mine water monitoring network. After the closure of the mines in South Limburg (late 1960s, early 1970s), the pumping systems that kept the mines dry were stopped. Since then, the mine water has continued to rise. The Ministry of Economic Affairs has therefore instructed the Province of Limburg to conduct more extensive research into the extent of the increase and quality of this mine water. For these reasons, seven new wells are being drilled. These wells are each fitted with three filters with a filter depth varying from approximately 40 to approximately 400 m below ground level. The hydraulic head of the groundwater is measured, and all filters are sampled. After the first year, the measurement and sampling regime for the coming years will be evaluated and co-ordinated.'

There are many advantages to working with the Grundfos MP 1 pumps. The MP 1 pumps deliver an impressive flow rate and have sufficient head. The latter is important because the groundwater in mine water wells is usually located at great depths. In addition, the diameter of the pump is suitable for most monitoring wells. The pumps are easy to install and made of a relatively inert material, so they do not contaminate the samples.