Hydrodynamic and contaminant transport modelling of ground and sea water in the Bagnoli area

Transcription

1 Hydrodynamic and contaminant transport modelling of ground and sea water in the Bagnoli area Campania Science & Technology Week in Beijing China Millenium Monument, May 2007 F. Pirozzi, M. Greco, A. Carravetta, D. Vicinanza and M. Ribera d Alcalà Raffaele Cesaro AMRA

2 Bagnoli-Fuorigrotta depression

3 Beginning of XX century

4 XX Century Industrial (e.g. Metallurgy) development of the area Stopped at the end of the XX century

5 Soil and groundwater alteration Industrial activities Waste material derived from mechanical and metallurgical processes were disposed on site Bagnoli area is an Italian national interest site for soil and groundwater contamination

6 Downloaded by BagnoliFutura S.p.A. Urban planning

7 Preliminary investigations on Bagnoli Area Investigated points n Soil Samples n Analyses heavy metals Analyses organic compounds n n Wells n 71 Samples n 221 Analyses n Volume of waste material disposed m³ Volume of contaminated soil m³

8 Soil and groundwater treatment Soil treatment Ex-situ treatment using soil washing Treated soil will be both disposed and reused Groundwater treatment Physic-chemical treatment by means of in-situ hydraulic barriers

9 Objects of this study Development of an hydrodynamic and contaminant transport modelling of ground and sea water in the Bagnoli area 1. Generalization of hydraulic groundwater circulation in the area based on direct analyses; 2. Generalization of sea water circulation in the area; 3. Report the soil and ground and sea water contaminations spatially 4. Evaluation of the operations that have been or will be carried out on the area regarding contamination phenomena

10 Operative phases 1. Acquisition, analysis and interpretation of the data available by BagnoliFutura S.p.A; 2. Development of mathematical model; 3. Choice of the interesting scenarios; 4. Utilization of calculation codes

11 Operational phases of this study Groundwater circulation

12 Operational phases of this study Groundwater circulation Sea water circulation

13 Operational phases of this study Groundwater circulation Sea water circulation Results

14 Groundwater model circulation Groundwater is quite close to the terrestrial surface. It moves mainly from NE-SW up to the sea

15 Geological and hydro geological model construction Sezione Seven different soil types up to -50 m (tuff layer)

16 Implementation of hydrodynamic model Regular grid: cells Numerical resolution for each fixed time length of hydrodynamic threedimensional equation for a medium porous, heterogeneous, anisotropic x K xx h x + y K yy h y + z K zz h z W = S s h t Input parameters Permeability in each cell; initial value of piezometry; boundary values of gradient pressure and piezometry; density in each cell.

17 Permeability The permeability values on each vertical was hypothesized based on an input for each soil layer according to the ratio between the average diameter of the granulometric curve k1e1 = k2e2 =... knen = c d i c d i i 2 50i,1 c d e 2 50i,2 i,1 e 2 50i, N i,2 e i, N

18 Boundary conditions Available groundwater level The simulation was performed considering the hydraulic barrier close to the littoral zone that is pumping and treating groundwater

19 Contaminant distribution Transport model consider desorption, adsorption and decay of single substrates along with interactions between chemical species Initial condition: equilibrium between solid and liquid bulks Based on advection-dispersion transport equation Two models: Based on Montecarlo approach ϑc t k = k k k ( qc ϑ D C ) + R + R C s w 0 ϑc t k = k k k ( qc ϑ D C ) + R + R C s w 0 D xx = D ( α α ) v v v + α v + / * L T i j

20 Transport model Non reactive contaminant Initial condition Residual concentration

21 Transport model Reactive contaminant Initial condition Residual concentration

22 Sea water circulation The data delivered by this model were used as inputs for the sea models Coastal antropic and natural systems Meteorological study Littoral zone model Sea circulation model Contaminant transport 240 N 175 N

23 Model for sea water circulation RIFRACTION-DIFFRACTION MODEL LITTORAL AND SEA WATER CIRCULATION Available data Waves registration at Ponza float ( ); Anemometric registration at the APAT station in Naples Gulf; Coastal profiles provided by IAMC del CNR

24 Littoral zone hydrodynamics simulation

25 Littoral zone simulation With contaminant diffusion but not with hydraulic barrier working

26 Littoral zone simulation With contaminant diffusion along with hydraulic barrier working

27 Contaminant distribution in Bagnoli gulf

28 Winds from N-E 6-8 Febbraio Febraury 2005

29 6-8 Febraury 2005

30 Conclusions 1. It was delivered a suitable tool to investigate actual contamination and possible groundwater and soil treatment scenario 2. Bagnoli site is un-easy systems regarding geological, hydro-geological and contamination sides 3. The contaminant tend to stay in Bagnoli gulf diffusing in the sea very slowly; 4. The groundwater barrier greatly influence the groundwater and sea water circulation but also contaminant diffusion 5. The study can be upgraded considering sediment contamination

31 Thank You very much for Your attention