Application example: Nitrate monitoring in leachate

Density of ecoTech monitoring stations increasing throughout Germany

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Instigation
In many regions of Germany, the nitrate pollution of ground and surface water has remained high over many years. In order to better understand the causes of this pollution, within the context of the agricultural sector, the BEW (Bocholter Energie- und Wasserversorgung GmbH), responsible for the waterworks in 2011, initiated new practices in pollution research and monitoring. The goal was to determine the actual nitrate discharge into the leachate using modern testing methods. As a result of this initiative, ecoTech was commissioned by other water utilities in the western region of Münster to build eight newly designed nitrate monitoring stations across four municipalities in 2012 and 2013 (see NRW map).

Background
The technical objective of the surveys was to determine and clarify the effects of fertilization, soil processing, crop rotation and weather conditions on nitrate release. To achieve this, the BEW and ecoTech developed a new nitrate-monitoring concept, which differed significantly from previous technical solutions. The goal was to permanently monitor the nitrate concentrations in the leachate of typical arable land still under full agricultural management. In this case, the objective was to detect only the only leachate that gravitationally seeped from the root space into the groundwater.

October 2018: 2 First large-scale project in Saxony

ecoTech installs a leachate system on 12 plots as well as two soil moisture monitoring stations for Stadtwerke Leipzig GmbH (Wassergut Canitz).

December 2017: Pilot system in Baden-Württemberg

The Forest Research Institute (FVA) in Freiburg purchases one first suction plate system for a pilot project in Baden-Württemberg

October 2016: 2 new measuring systems in Saxony-Anhalt

The concept, which has been tried and tested in NRW, also attracted attention in other Federal States. In August 2016, ecoTech was commissioned by the State Agency for Agriculture and Horticulture in Saxony-Anhalt (LLG) to install two nitrate monitoring measuring points.

June 2016: 12 new locations in NRW
In 2016 the North Rhine-Westphalia Ministry for Climate Protection, Environment, Agriculture, Nature Conservation and Consumer Protection (MKULNV) financed a nitrate-monitoring project of the LWK NRW (Chamber of Agriculture Nordrhein-Westfalen). The aim of this innovative project was to provide comprehensive monitoring of nitrate discharges from agricultural areas in zones with particularly high nitrate levels in the groundwater. This data, gathered at a larger scale, will help the LWK to better understand the relationships, allowing them provide advice on streamlined land management practices and thus comply with the EU Water Framework Directive.

The new project uses the leachate collection technology already proven in the Münsterland and extends the existing concept of the BEW by two main factors: Firstly, at least two areas are compared and secondly all significant monitoring parameters are recorded at all measuring points (see below).

Following an invitation to tender, ecoTech GmbH was commissioned in June 2016 to supply and install the new leachate monitoring network. By November 2016, 25 leachate measuring stations had been installed at 12 new sites in NRW (see map NRW).

Accompanying measuring technology
New monitoring stations measuring important weather parameters and soil moisture at three depths now flank the leachate monitoring systems at these 12 new sites. The stations automatically send their data to a server of the Geological Service NRW (GD NRW). From this server, the data are processed, graphically prepared and made accessible to all interested parties on the homepage of the GD NRW (https://www.enviwatch.net/~gdnrw/anzeigen.html).
In 2007 the GD NRW had already commissioned ecoTech to construct of six such stations, so that today 18 stations collectively transmit their data to the Central Office (see NRW map).

2012: Improved technology
To realise this new nitrate monitoring concept, we at ecoTech further developed our tried and tested glass suction plates in various respects to ensure interference-free leachate sampling in the field over distances of 20 m and more (behind the tractor paths). To obtain only the gravitational leachate, the suction plates were installed in undisturbed soil at a depth of approx. 100 cm below the root area. The seepage water is then transferred to sample vessels with only a small negative pressure (for example, -60 hPa = field capacity).
Comparison measurements using other measuring techniques and a tracer experiment at the Bocholt site have shown that the concept provides representative results.

Product
Glass suction pads with special hose fittings
TensioMark
Vacuum controller
enviLog Midi with accessories
MeteoMS
  • Various water suppliers in the western Münsterland, NRW
  • North Rhine-Westphalia Chamber of Agriculture
  • State Department for Agriculture and Landscapes, Saxony-Anhalt
  • Forest Research Institute (FVA), Department of Soils and EnvironmentStadtwerke
  • Stadtwerke Leipzig, Wassergut Canitz
  • Bavarian State Institute for Viticulture and Horticulture