Crude oil and some petroleum products pose a risk to groundwater. During a lecture held at the Erdöl-Erdgas-Museum Twist, experts from the company Hölscher Wasserbau based in Haren, Germany, explained how damage can be repaired.
Head of Research and Development Josef Teiken and process engineer Sascha Schulte used project examples to describe how experts develop special solutions for their customers in order to solve their problems. Teiken started off by delving into one of the petroleum industry’s common issues. At the Vopak Dupeg Terminal Hamburg, petroleum products are transshipped between ship, rail and road in the port. The rainwater running off the port was pretreated in the city of Hamburg’s sewer leading to high post-treatment costs. Hölscher Wasserbau was given the task of post-treating the water from the oil separators in such a way that it fulfils the strict standards governing the discharge into the Rethe waterway.
Process engineer Schulte explained how a sophisticated filtration system was used in Hamburg to achieve success. High safety precautions had to be met at the demand of the regulatory bodies. Samples were taken on a weekly basis before the water was discharged in the Rethe waterway on February 1, 2018. Teiken also explained that the purified water can be used as process water.
WTD 91 remediation
Schulte is in charge of groundwater remediation at the German Federal Armed Force’s defense technology center (WTD 91) in Meppen, Germany. Large quantities of the hazardous chemical trichloroethylene leaked during a system breakdown and caused an “extremely high” amount of pollution, as described by Schulte. Samples from inspection wells showed that the groundwater pollution spread all the way to Meppen-Borken. Water has therefore been pumped out of the upper aquifer and cleaned on the WTD site since 2007. In 2017, four wells were drilled into the second aquifer near Borken.
(https://www.noz.de/lokales/meppen/artikel/992069/grundwassersanierung-in-meppen-kommtvoran#gallery%260%260%26992069) The water taken from it is cleaned and drained away so that it’s only necessary to intervene with natural groundwater on a minimal scale. “Everything’s running smoothly thus far,” says the process engineer.
Peat and Sand
While developing Hamburg’s industrial park Neuland 23, Emsland specialists found a solution to a problem they are all too familiar with from their hometown. There is a layer of peat measuring up to six meters in thickness that covers the entire 25 hectares of land. The idea, which was taken from Haren, is to remove the water from this layer of peat to compact it, while simultaneously applying sand to the top layer upon which the extracted water is drained off. This helps to prevent a reduction in the amount of groundwater. Teiken explained that a sufficient load-bearing capacity for buildings and traffic areas can therefore be provided by compacting the layer of peat. The water from the peat layer, however, is rich in iron which actually prevents water from seeping into the applied layer of sand. The mineral is inexpensively recovered from the renewable resource potato starch in large basins. Hölscher developed this process in collaboration with Emsland-Stärke GmbH from the municipality of Emlichheim, reports Teiken.
This procedure used in the industrial park in Hamburg raised the question as to whether this procedure can be used as a solution for roads in Emsland. After all, Landesstraße 47’s road in Twist is all rippled due to the layer of peat in the embankment. Teiken explained that this could be tested.
Hölscher has a test field in Haren that it uses for developing new processes. One observation was made here, said Teiken: the quality of the groundwater is worsening due to the nitrate in fertilizer. The quality of drinking water in Emsland is still excellent, however, the nitrate pollution will have to be reduced in order to maintain these good values in the future.
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