Aquarehab > Output > Technology models

Technology models

To evaluate the impact of remediation technologies on water quality over time and space, technology models were developed by mathematical modellers with input from technology developers. The technology models worked out within AQUAREHAB are related to a specific technology and aim

  1. to develop reactive transport codes and hydrological models for simulating pollutant removal in riparian zones, river beds and groundwater,
  2. to help design experimental work related to the technologies,
  3. to evaluate models on various cases and generalize the model results, and
  4. to develop a common modelling framework for incorporating model results into catchment scale models.

Typical users are water managers, consultants, land owners

Some examples of models developed are:

Technology Code Processes included/characteristics of the model
Wetlands
(WP1)

(Figure 25)		 FeFlow (Diersch, 2005)

Feflow 6.0 was used to simulate 2D flow and reactive transport.
http://www.feflow.info/
  • 2D variable-saturated steady-state flow and multi-species transport
  • redox-zone dependent sequential first-order degradation of agrochemical compounds and metabolites. It is assumed that denitrification occurs sequentially from NO3->NO2->½N2, with each step governed by a first-order reaction.
Smart carriers in field drains
(WP2)		 Hydrus-1D (Simunek et al., 2013)

User manual and notes on how to use HP1:
http://www.pc-progress.com/en/Default.aspx?hydrus-1d
  • Solute advection and dispersion (in one dimension): flow in the trench is conceptualised as 1D flow
  • Sorption: depending on the carrier material used, the sorption properties will differ
  • Degradation: degradation is incorporated in the model as a first-order reaction process with temperature dependency
  • Heat transport: important for the technology is to know how the performance alters with temperature; therefore a heat flow equation was used to estimate the temperature in the trench.
Groundwater river interaction zones
(WP3)		 PHREEQC

VS2DH (Healy and Ronan, 1996

The HP1 code is fully incorporated into the Hydrus-1D (Simunek et al., 2013)
  • A first-order model in containing advective-dispersive solute transport with first order degradation was developed to represent the degradation of VC in the river sediment.
  • The flux exchange between the groundwater and surface water across the stream bed interface was initially estimated by using a two-dimensional, finite difference variably saturated, groundwater flow and heat transport model

These two approaches were finally combined in the HP1 model to facilitate data management and processing using only one software tool for the simulation of the processes near/in the hyporheic zone.
(multi)Barriers
(WP4)

(Figure21)		 MIN3P (geochemical model)

MODFLOW and PHAST PHREEQC		 Reaction model used to predict barrier longevity simulates groundwater flow and multi-component reactive transport. Fifty three complex aqueous reactions and 3 mineral phases were included. Sixteen dissolved species were also included in the model to reproduce the concentrations profiles: perchloroethylene (PCE), trichloroethylene (TCE), trans-dichloroethylene (t-DCE), cis-dichloroethylene (cis-DCE), vinyl chloride (VC), ethene, Ca2+, Cl-, Na+ , Fe2+, Fe3+, S6-, S2-, TIC (total inorganic carbon), H+ and H2.
Injectable iron
(WP5)		 PHREEQC model

MNM1D (Tosco T. et al., 2010)		 To simulate observed geochemical changes from a batch experiment performed with one iron type.

Simulation of the iron concentration in the soil matrix

The software that was used to construct the technology models have to be bought by the user on a license-fee basis. More details related to the software, the contact details of the partner and the input files for the different case studies and case descriptions is accessible here.