SLIDE 1 www.innovatie.waternet.nl
Plant wide chemical water stability modelling with PHREEQC for drinking water treatment
Alex van der Helm Waternet / Delft University of Technology Onno Kramer Waternet Jos Hooft Waternet Peter de Moel Omnisys/ Delft University of Technology 2nd IWA New Developments in IT & Water Conference, Amsterdam, the Netherlands, February 10th 2015
SLIDE 2 Waternet
Water cycle company of Amsterdam:
- Drinking water production and distribution
- Waste water collection and treatment
- Water system management
- Water safety (dikes)
- Nautical and waterway control
SLIDE 3 Calculating in PHREEQC
pH – Redox – Equilibrium – Calculations
- developed by US Geological Survey (USGS)
- scientific base, fully traceable
- adapted to newest scientific knowledge
- users can modify and extend the basics
- communication with MS Excel possible
- freely available
SLIDE 4 Calculating in PHREEQC
pH – Redox – Equilibrium – Calculations
- 25 elements
- Liquid, gas and solid phase
- 8 databases with equilibrium constants
SLIDE 5 Stimela.dat
De Moel et al. (2014) developed PHREEQC database Stimela.dat for water treatment Inert elements were defined for:
- Oxidation states of nitrogen NH4
+, N2, NO2
- Anaerobic groundwater species Fe2+, Mn2+
- Anaerobic gases CH4, H2S, NH3
SLIDE 6
Drinking water treatment plant
SLIDE 7 Amsterdam
Drinking water treatment plant
Weesperkarspel
Pre-treatment
Loenderveen
Source
Bethunepolder
Loenderveen-Weesperkarspel
SLIDE 8
Lake water reservoir
SLIDE 9
“Raw water” parameters
SLIDE 10
Raw water parameters
SLIDE 11
Raw water evaluation with Stimela.dat
Calculated Oxygen saturation Calculated carbon dioxide concentration
SLIDE 12
Calculated Saturation Index Calculated calcium carbonate precipitation potential
Raw water evaluation with Stimela.dat
SLIDE 13
Calculated ionic balance Calculated EGV ratio
Raw water validation with Stimela.dat
SLIDE 14
Treatment scheme
SLIDE 15 Modelled chemical processes
Process Item Reaction pH control HCl-dosing HCO3
- + H+ + Cl- -- > CO2 + H2O + Cl-
Filtration NH4-oxidation NH4
+ + 2 O2 + 2 HCO3
Ozonation O3-reduction 2 O3 -- > 3 O2 Softening NaOH-dosing CO2 + OH- + Na+ -- > HCO3
NaOH-dosing HCO3
2- + Na+
CaCO3-crystallization Ca2+ + CO3
2- -- > CaCO3(s)
pH control HCl-dosing CO3
2- + H+ + Cl- -- > HCO3
AC filtration DOC-oxidation CH2O + O2 -- > CO2 + H2O pH control NaOH-dosing CO2 + OH- + Na+ -- > HCO3
O2 control O2-dosing O2 -- > O2 SS filtration DOC-oxidation CH2O + O2 -- > CO2 + H2O
SLIDE 16
SI and Total Hardness (TH)
4 Setpoints in the treatment
SLIDE 17
SI and Total Hardness (TH)
4 control points in the treatment
SLIDE 18
SI and Total Hardness (TH)
4 influencing processes in the treatment
SLIDE 19
SI and Total Hardness (TH)
Simulation with Stimela.dat
SLIDE 20
PHREEQC code in MS Excel
SLIDE 21
Results inprocessdashboard
SLIDE 22
Multiple simulations
Long term process evaluation
SLIDE 23 Multiple simulations
Effect on drinking water quality:
- Stable SI
- Slightly varying pH due to temperature
SLIDE 24 Conclusions
- Accurate chemistry available for process
technologists with Stimela.dat in PHREEQC
- Chemical dosages can be optimised
- Improving chemical stability of drinking
water
- User interface simply build and adapted in
MS Excel
SLIDE 25 www.innovatie.waternet.nl
Plant wide chemical water stability modelling with PHREEQC for drinking water treatment
Alex van der Helm Waternet / Delft University of Technology Onno Kramer Waternet Jos Hooft Waternet Peter de Moel Omnisys/ Delft University of Technology 2nd IWA New Developments in IT & Water Conference, Amsterdam, the Netherlands, February 10th 2015
