Tracerexperiment uitgevoerd in april/mei 1996 ten behoeve van de In Situ Biorestauratie te Asten
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Series / Report no.
Open Access
Type
Report
Language
nl
Date
1997-09-30
Research Projects
Organizational Units
Journal Issue
Title
Tracerexperiment uitgevoerd in april/mei 1996 ten
behoeve van de In Situ Biorestauratie te Asten
Translated Title
A tracer experiment carried out in April/May 1996
in the framework of the project "In Situ Bioremediation" in
Asten
Published in
Abstract
Ter afsluiting van de praktijksanering in het kader van
het project "in situ biorestauratie van een met olie verontreinigde bodem",
is een tracerexperiment op de locatie te Asten uitgevoerd. Bij deze
saneringstechniek wordt gebruikt gemaakt van water om zuurstof (in de vorm
van waterstofperoxyde) en nutrienten aan de locatie toe te voeren ter
stimulering van de microbiologische afbraak van de verontreiniging. Voor
een goed eindresultaat is het van belang dat de bodem uniform doorstroomd
wordt. Het doel van het tracerexperiment was na te gaan in hoeverre dit
bereikt is door de stroombanen en verblijftijden van het grondwater te
onderzoeken. In het infiltratiewater werd chloride gedoseerd; door
metingen in alle 25 onttrekkingen werden doorbraakcurves bepaald. Tussen de
onttrekkingen traden grote verschillen op in het moment van
chloridedoorbraak, maar de onderlinge resultaten in drie gebiedjes op de
locatie vertoonden overeenkomsten. Met name in het gebied ten oosten van de
bedrijfswoning begon de chlorideconcentratie al snel op te lopen en trad na
ongeveer 235 uur doorbraak op. In de onttrekkingen ten westen van het
tankeiland is geen doorbraak gemeten. De verschillen in doorbraaktijd
kunnen waarschijnlijk toegeschreven worden aan de bodemkarakteristieken
zoals bijvoorbeeld de doorlatendheid. Aan de hand van de resultaten uit het
tracerexperiment kunnen de grote verschillen die te zien zijn in de gemeten
benzinegehaltes in de bodem en -concentraties in het grondwater verklaard
worden.
The aim of the tracer experiment, carried out in the framework of the project 'in situ bioremediation of oil polluted soil' in Asten (Noord-Brabant) at the end of the remediation on a commercial property and a tank island, was to trace to what extent the infiltrated water flowed uniformly through the soil. This was done by studying the flow paths and residence times of the groundwater from 25 withdrawals. In the remediation technique chosen, water was used to supply oxygen (in the form of hydrogen peroxide) and to bring nutrients to the location to stimulate the microbiological degradation of pollutants. Chloride was applied to the infiltration water in such doses as to bring the chloride concentration to about 400 mg.l-1. The concentration was measured daily in all 25 withdrawals. The measuring frequency was increased the moment the concentration in the withdrawal rose to 2 or 3 times a day. Breakthrough curves were determined in this way. Although large differences in withdrawals were observed at the moment of chloride breakthrough, the results in three of the areas within the location did show some similarities. The chloride concentration started to rise soon after the start of the experiment and broke through after 235 hours in the area to the east of the commercial property. In the withdrawals on the west side of the tank island no breakthrough was measured, and in some withdrawals there was not even a rise in the concentration. The differences in breakthrough times can probably be ascribed to soil characteristics, for example, the permeability. The differences in breakthrough times could explain the large differences between the concentration levels of petrol measured in the soil and concentrations of petrol in the groundwater.
The aim of the tracer experiment, carried out in the framework of the project 'in situ bioremediation of oil polluted soil' in Asten (Noord-Brabant) at the end of the remediation on a commercial property and a tank island, was to trace to what extent the infiltrated water flowed uniformly through the soil. This was done by studying the flow paths and residence times of the groundwater from 25 withdrawals. In the remediation technique chosen, water was used to supply oxygen (in the form of hydrogen peroxide) and to bring nutrients to the location to stimulate the microbiological degradation of pollutants. Chloride was applied to the infiltration water in such doses as to bring the chloride concentration to about 400 mg.l-1. The concentration was measured daily in all 25 withdrawals. The measuring frequency was increased the moment the concentration in the withdrawal rose to 2 or 3 times a day. Breakthrough curves were determined in this way. Although large differences in withdrawals were observed at the moment of chloride breakthrough, the results in three of the areas within the location did show some similarities. The chloride concentration started to rise soon after the start of the experiment and broke through after 235 hours in the area to the east of the commercial property. In the withdrawals on the west side of the tank island no breakthrough was measured, and in some withdrawals there was not even a rise in the concentration. The differences in breakthrough times can probably be ascribed to soil characteristics, for example, the permeability. The differences in breakthrough times could explain the large differences between the concentration levels of petrol measured in the soil and concentrations of petrol in the groundwater.
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DGM/Bo