Contaminated sites remediation: examples of application of pure oxygen for the removal of pollutants in groundwater

Transcription

1 removal of pollutants in groundwater Bonifica di siti contaminati: esempi applicativi dell'ossigeno puro per la rimozione di inquinanti nelle acque di falda Ing. Giorgio Bissolotti Gas industriali, Engineering, Healthcare, Beni industriali e Servizi

2 Contaminated sites remediation: examples of application of pure oxygen for the Oxygen Environmental sustainability Other gases involved Results

3 Production Electrolysis energy, membranes Membranes Pure Oxygen Adsorbtion Energy, siliconaluminates materials (sodium silicate, sodium hydroxide, aluminium hydroxide) Cryogenic separation (energy)

4 Why we use pure oxygen? Oxygen is present in air at 20,9 % in volume (23% in mass). Chemical and biological reaction are influenced by oxygen concentration. If the oxygen concentration is 5 times more, the speed of the reaction improve consequently We need to balance the cost (mainly energy) with the advantage to improve the reaction Oxygen is used since long time in wastwater treatment (adese and suspended biomass) In this last years its use for the undeground pollution is improving

5 The release of biodegradable contaminants into water bodies determines the general lowering of the level of dissolved oxygen Biodegradable compound (ex. Hydrocarbons) Microorganism aerobic Oxygen (4050 mg/l) Aerobic biodegradation microorganism autochthonous.

6 A) Model of the site (lithostratigraphic) B) To know if the oxygen can arrive in all the site. Estimate the time to have the complete degradation of pollutants. Evaluate the quantity of the pollutants ( always have a non uniform distribution) or discover other pollutants. use of tracer gases (neon e kripton) estimation of the range of influence of each well; measure of parameters index: dissolved oxygen, redox, ph,..

7 GAS INJECTION SYSTEM IN GROUNDWATER REMEDIATION SITES GROUND BIO2 gas: pure oxygen target: bioremediation GROUND MIX gas: mixture of pure oxygen and tracer gases (helium, neon, krypton) target: bioremediation, range of influence of GROUND BIO2 GROUND SPY gas: tracer gases (helium, neon, krypton ) target: range of influence of a remediation thechnology PATENTED SYSTEM Sistema per la decontaminazione delle acque sotterranee mediante iniezione in situ di gas ossidanti e/o riducenti. N depositato Groundwater decontamination system through in situ injection of oxidant and/or riducent gases. EP A1 pubblicato il Metodo per dimensionare i sistemi di diffusione di gas in falda e valutare la presenza di inquinanti tramite l utilizzo di miscele di gas. N depositato il Method based on the use of gas mixture for sizing systems of gas diffusion in groundwater and valuating the aquifer contamination. N depositato il

8 GAS INJECTION SYSTEM IN GROUNDWATER (GROUND BIO2 MIX SPY) Description Cylinders or bundles Pressure reducer Flowmeter pipes Diffuser 12 m 6 m

9 Contaminated sites remediation: examples of application of pure oxygen for the PURE OXYGEN INJECTION SYSTEM IN GROUNDWATER GROUND BIO2 Installation

10 Contaminated sites remediation: examples of application of pure oxygen for the PURE OXYGEN INJECTION SYSTEM IN GROUNDWATER GROUND BIO2 Installation Decommisioned site Operating site

11 GAS INJECTION SYSTEM IN GROUNDWATER GROUND SPY Tracer gases (Helium, Neon, Krypton) to evaluate range of influence Pressure reducer Test on Multi Phase Extractions Flowmeter Manometer Cylinder Injection well

12 PURE OXYGEN INJECTION SYSTEM IN GROUNDWATER GROUND BIO2 Advantages and disadvantages ADVANTAGES In situ treatment Promoting the activity of natural degradation Absence of volatilization phenomena No waste production No energy consumption Cost effective Low impact on the operating site Simple installation and management DISADVANTAGES Site specific conditions suitable for application of a biotechnology Medium long recovery times compared to technologies faster but more invasive Oxidation parasites Necessity of rebound phenomena monitoring

13 Bioremediation Feasibility Test Laboratory scale Aerobic test 100% removal HC and benzene Anoxic test 65% removal HC and benzene Abiotic test negative control The aerobic metabolism is more powerful than anoxic one (natural attenuation) OUR (mgo2/l/d) Tempo (d)

14 GAS INJECTION SYSTEM IN GROUNDWATER GROUND BIO2 MIX Mixture of pure oxygen and tracer gases Tracer gases: inert gases (neon, krypton) with pure oxygen injected into the groundwater to determine the range of influence of Ground Bio2. The inert gases are not subject to consumption for biological activity or for chemical reactions in situ, and then allow to identify the speed of advance of the front of the gas. The range of influence varies in function of the characteristics specific site. On average, it is estimated in 35 m in one month.

15 GAS INJECTION SYSTEM IN GROUNDWATER GROUND BIO2 Pure oxygen allows the complete removal of pollutants through the stimulation of naturally occurring bacteria in groundwater

16 Conclusions Use of oxygen, o low environmental impact substance. Use of autochthonous bacteria. Pure oxygen reduce the time to reach the degradation of pollutant substances. The use of others gases can help to identify the location and the quantity of pollutants (and to discover other pollutants) Could be used as a barrier to stop the plume of pollutants. The chain, from the production of oxygen to its use, as a footprint constitute mainly in the energy necessary to produce oxygen and transport. its

17 GRAZIE DELL ATTENZIONE

18 PURE OXYGEN INJECTION SYSTEM IN GROUNDWATER GROUND BIO2 Technology features Technology for insitu removal of contamination dissolved in ground water Stimulates the activity of aerobic bacterial autochthonous: increase the kinetics of biological degradation Suitable for hydrocarbon contaminations (HC, BTEX, MTBE) Green technology based on pure gas diffusion in water (concentration gradient, transport of groundwater) Absence of phenomena of stripping No waste production Does not require electricity: it utilizes the potential energy of the compressed gas Compact system with the possibility of underground installation Ability to conduct remediation with operating sites Ease of Management Range of influence of the order of 36 meters in 30 days