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Subterranean removal of Fe and Mn in deep ground water. A case study in Upper Austria. Jung, M.; Spendlingwimmer, R. & Höfinger, G. / Water. Introduction. Background Geology - Ground water Ground water chemistry Objective Operation plan - model Operation Conclusion.
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Subterranean removal of Fe and Mn in deep ground water A case study in Upper Austria Jung, M.; Spendlingwimmer, R. & Höfinger, G./ Water
Introduction • Background • Geology - Ground water • Ground water chemistry • Objective • Operation plan - model • Operation • Conclusion
Background – Regional settings • Regional water supplier • ~70.000 people • Many sources from different ground waters, but Wellfield Schörgendorf • Zirking: shallow well field • Nitrate (~40 mg/l) • Hardness (23°dH ~ 4,1 mmol/l Blending with soft water from deep auqifers Wellfield Zirking
Mauthausen Schörgendorf Gallneukirchen Background - Geology • Widespread, confined sandy aquifer (Linzer Sand) • High permeability (Schörgendorf) • Good infiltration and renewal • Pumping tests 30 l/s • Low total hardness (ion exchange) • No anthropogenic contamination (nitrate, pesticides,…) • but …..
Background – Ground water chemistry • Calcium-sodium-hydrogencarbonate-water • Low nitrate, sulfate and oxygen concentrations due to ion exchange (Ca-Na-SO4) • Geogen caused oxygen reduction G reduction of nitrate • high ammonium concentrations - 1,7 mg/l • high manganese concentrations - 0.17 mg/l (Fe ~ 0.03 mg/l) • high flouride concentrations - 1,8 mg/l • Water treatment required
Objective Ammonium, iron & manganese removal Ex situ treatment In situ treatment 4 wells in alternating operation (reinjection & production) Aeration (ex situ) Reinjection of the aerated water (part)
General idea Reinjection of aerated water Groundwater withdrawal GW-level Aquiclude (Schlier) Mn-precipitation Fe-precipitation Aquifer
4h Operation plan Injection of oxygenated water Withdrawal of groundwater for treatment Exclusive withdrawal into the distribution network withdrawal into the distribution network
Conclusion • ~22 l/s treated ground water from a deep aquifer • Objectives met (removal of NH4, Mn, [Fe]) • Nitrate ~15 mg/l • Total hardness 15°dH ~ 2,67 mmol/l • Operation plan adapted • Accompanying monitoring!!! • 12 months „running- in“ time!!!