VERSITy 16. OCTOBER 2012 UNI PEDER MARIBO GROUNDWATER CONTAMINATION AND TREATMENT

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER 2012

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER 2012 AARHUS CITY: 300,000 inhabitants – 60,000 students

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER 2012 URBAN WATER (Environment & Infrastructure) AUTUMN semester (30 ECTS): Wastewater Engineering: sewer systems - treatment plant – recipients SPRING semester (30 ECTS): Water Supply Engineering: withdrawal – treatment - distribution

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER GW monitoring, Chemical status state-and-impacts-poland/fig.-5-assessment-of-the GROUNDWATER Contamination & Treatment EU water framework directive Groundwater: – Good chemical quality - Quantity managed

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER Contami- nation Point source Non-point source agenda GW-table GW well Water works (filtration) Aquifer Soil surface

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER EEA GW CONTAMINANTS ”Non-point sources”: Pesticides

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER EU drinking water directive 98/83/EC Pesticide: < 0.1 µg/L (∑ Pesticides: < 0.5 µg/L)

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER 2012 Soil surface 9 Contami- nation Point source Non-point source Risk? qiqi q GW Dilution Transport & transformation Effect?

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER Water soluble substances Organic chemicals (BTEX, MTBE, phenols, halogenated…) Metals (e.g. As, Cr, Cu… Primarily in reduced, acidic waters) AIR WATER (dissolved) PARTICLES (sorbed) KdKd KHKH

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER Contami- nation Point source Non-point source Risk? qiqi q GW Dilution Transport & transformation Effect? Remediation? Prevention GW quality management…

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER Water treatment Combination of unit operations Physical Biological Chemical Sorption (GAC) Separation Filtration (particles) Membranes Stripping (volatiles) Precpitation (e.g. metals) Oxidation (metals, organic matter) Moderation of general env. (pH, redox, …) Oxidation (organic matter, NH 4 +, metal ions) Uptake in biomass.

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER 2012 bubble bassin INKA free fall - droplets Cascade aeration

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER 2012 MASS - TRANSFER TWO-FILM THEORY (SHOWN FOR STRIPPING) phase interface water film water bulk air bulk air film ybyb yiyi CiCi CbCb mixing diffusion Henry’s constant

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER CASE: Valby gasworks Gasworks: Tar, heawy metals (As..), BTEX, HCN. GW: primary problem BTEX (benzene). Level in aquifer: 0.9 mg/l Water 15 m3/h. 15 mg benz/h Air 50 m3/h 2 x 260 kg GAC. Capacity 2.2 g Benzene/kg GAC 3.2 m high packed towers, cunter current Ref: Falkenberg, J.A. (1999) DEPA miljøprojekt 492. K h,benz =0.25

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER 2012 Activated Carbon Filtration (Adsorber) SORPTION: GAC – granular activatred carbon Water or stripped air

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER For higher concentration: Chemical + biological oxidation (O 3, Cl 2, KMnO 4, … )

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER 2012 Unit operation(s)Removal ofRemarks StrippingMTBE, some pesticides, light hydrocarbons. Possible pH adjustment. Temp. Gas phase treatment needed (e.g. incineration or GAC) Precipitation + settlingHeavy metals (As, Cr, Cd..) Acidic waters, land fill leachate, wood creosoting sites, gas work sites.. pH adjustments. Possibly chemical oxidation. Addition of complex binders (e.g. EDTA), polymers and co-precipitation metals. Sorption (GAC)Organic components + metals At low concentrations. As polishing step after chemical or biological oxidation Chemical oxidation Non-biodegradable subst. (e.g. toxic or long chain OM). Pretreatment for land fill leachate. Oxidizing agent. Possibly pH adjustment Pretreatment before biological treatment or GAC Biological treatment (+ settling, and/or filtration) Organic matter and NH (biodegradable – i.e. primarily short chain OM). Land fill leachate. pH adjustment. Hydrocarbons: Nutrients needed Landfill leachate: inhibition !? MBR (membrane bioreactors) Complex organic compounds. Land fill leachate. 18 Choice of treatment train

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER 2012 Forced leaching

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER 2012 › Many wells affected (8 % of wells) › A new (deep) well: – Euro › Often arsenic in «moderate» levels (1 – 10 µg/L) › Water with arsenic at the limit value (10 µg/L) has a toxic effect 1000 times higher than water with pesticide at the limit value (0.1 µg/L).... !! 20 Case DK: Pesticides

GROUNDWATER – CONTAMINATION & TREATMENT PEDER MARIBO 16. OCTOBER thank you