1. Student: Anja Randjelovic Mentors: Nenad Jacimovic, Ana Deletic
Micropollutants in Water Sensitive Urban Design systems Part of TR37010: Urban Drainage Systems as Key Infrastructures in Cities and Towns
Hello everybody,
My name is Anja, I am from the Faculty of Civil Engineering in Belgrade
I will present part of my research I have done in Melbourne, with people from Centre for Water Sensitive Cities
This collaboration between two universities – Belgrade and Monash, has been part of our Research project Urban Drainage Systems as Key Infrastructure in Cities and Towns
Student: Anja Randjelovic
Mentors: Nenad Jacimovic, Ana Deletic
Blue Green Dream Workshop

2. Blue Green Dream Workshop 26.04.2013.
Micropollutants?
Industrial chemicals, flame retardants, pharmaceutically active compounds and their metabolic products (even heavy metals)
Present ubiquitously in the aquatic environment in orders of micrograms and nanograms per liter
Conventional treatment systems cannot “cope” with them
EU Water Framework directive – list of priority pollutants (to be revised every four years)
Annex II
of Directive
2008/105/EC
What are micropollutants and why are they already important and becoming even more and more?
These are chemicals, mostly industrial, man-made, which don’t have a common behaviour mode; they can be organic or inorganic, include polycyclic aromatic hydrocarbons, phtalates, phenols, detergents, pharmaceuticals, hormones, heavy metals...
Their common characteristic is that there are only in traces in the environment (micrograms, nanograms per liter), but unfortunately even this small amounts can cause rather harmful effects – on both aquatic life / plants, animals, but mostly important – humans, and our metabolic system, can cause cancer, and various different system defects...
Conventional systems don’t do well with them, and they continue to substantially accumulate in the environment
They have been identified even through some of the international legislative – as priority pollutants: ie. European Union’s Water Framework Directive has so far identified 33 priority pollutants, and this list still isn’t final.. It is an ongoing research
Blue Green Dream Workshop

3. Sources of micropollutants
Life habits of present day population: polymer construction materials, paints, detergents, pharmaceuticals, pesticides...
Point sources – industries, medical waste, conventional waste water treatment plants
Diffuse sources – entire urban or rural catchment
Due to the persistence, the bioaccumulation potential and the toxicity of micropollutants, it is necessary to minimize their input into the sewage system and water bodies.
Since these micropollutants come from our every day habits, a very systematic approach is needed to deal with them.
There are sources which are more controllable – point sources, and sources which are getting more and more attention, and those are the diffuse ones – and stormwater as one of the big carriers of pollution.
Since these pollutants exist in such small quantities, it is sometimes difficult, if not impossible, to measure them... So what is needed is an integral approach – coupling of modelling techniques with measurement data and laboratory studies
Blue Green Dream Workshop

4. Water Sensitive Urban Design Systems
Gross Pollutant Trap
Buffer Strip
Vegetated Swale
Systems less suspected to help with micropollutants
A bit about Water Sensitive Urban Design systems – some of you might know them under different names, so I have included pictures, and terminology used in ie. Australia.... These types of systems are do not have our trust in possibility of mitigating micropollutant concentrations.
Blue Green Dream Workshop

5. Water Sensitive Urban Design Systems
Constructed Wetland
Detention pond
On the other hand, systems which have a more complex microcosmos – natural types of bioreactors like wetlands – shallow waters with characteristic plant system, detention ponds – depressions in terrain with or without permanent pool of water, .....
Blue Green Dream Workshop

6. Water Sensitive Urban Design Systems
Biofiltration System
And biofilters – specific types of man made filters – of natural materials, planted with certain types of plants,
For all of them there are high hopes in possibilities for removing pollutants. Ie. Biofilters have shown to be quite effective in removing sediments and to some extent nutrients, especially parts which are mostly in particulate state (like phosphorous)
Infiltration System
Blue Green Dream Workshop

7. Blue Green Dream Workshop 26.04.2013.
Modelling concepts
Conceptual models
Simple mass balances
Modular – possibilities for integrated modeling
Quantity detached from quality module
Catchment, routing, treatment system...
Flexible
Quality modules – processes/fate of pollutants governed by their inherent properties.
Use of available data
Ie. Inherent properties of micropollutants – use of public databases
Catchment
WSUD
Routing
Now, as mentioned earlier.... To have an integrated approach to resolving the trouble with micropollutant – we need to develop models that can be used complimentary with measurements of certain parameters, micropollutants themselves, or their surrogates... In our preliminary study we have decided on conceptual model family, which are mostly based on simple mass balances...
As we anticipated that these types of models will be at some point used to simulate much more integrated environment, like that is your plan with the blue green dream, we also decided to keep all parts of our model modular – so that they can be separated and combined with different – either quantity or quality models. Parts which I have made, are done in the dynamic environment of City Drain – platform developed at the University of Innsbruck under Wolfgang Rauch and his colleagues...
Like I have mentioned earlier... Other than quantity and hazardous effect on the environment, micropollutants don’t have too much in common... But still... some of them can be placed in groups that have similarities in behaviour in these systems. Ie, organic compounds have a high tendency of sorption to organic content of sediments – so this process can be simulated in a universal way for this type of chemicals... using different models of sorption.
Blue Green Dream Workshop

8. Blue Green Dream Workshop 26.04.2013.
Catchment
WSUD
Routing
Micropollutants before WSUD
1a. Catchment scale water quantity submodel
MOPUS (SymHid based)
1b. Sewer system routing
Muskingum - Cunge
Now I would briefly go through the modules....
First two are processes that happen on the catchment and the sewer network, if it exists... Model to be used for the catchment water quantity is simple, based on two reservoirs which represent impervious and pervious zone. Each reservoir has it subreservoirs, for which are defined state variables and connecting flows.
Routing of water quantity through the sewer network is done using Muskingum-Cunge routing method.
…to WSUD
Blue Green Dream Workshop

9. Blue Green Dream Workshop 26.04.2013.
Catchment
WSUD
Routing
Micropollutants before WSUD
2a. Pollution generation – EMC – stochastic
(MUSIC concept)
2b. Pollution generation – EMC – semi-stochastic
(Bach et al. 2010)
Modules which generate pollution on the catchment – are based on Event Mean Concentrations, and for them we would like to have two options: a pure stochastic one based on analysis of multiple catchments... do a random sampling from the assumed distribution and two distribution parameters – mean and st. Deviation
Other option is developed by Peter Bach – it is generation of event mean concentration based on the total volume of rainfall event – here on the graph, presented is the dependance of mean value of Event Mean Concentration from total volume of a rainfall event. This type of semi-stochastic process for pollution generation takes into account first flush phenomenons (as you can see, EMCs are larger for smaller cummulative volumes of runoff)
Blue Green Dream Workshop

10. Micropollutants in and after WSUD
Catchment
WSUD
Routing
Micropollutants in and after WSUD
3a. Water quantity - Dominant horizontal flow
Inflow
Outflow ET
Seep
Rain
Volume
Used for:
- Detention
Ponds
- Wetlands etc.
Stepping now into treatment systems – first we need to divide them into ones which have a dominant horizontal flow – like detention ponds, or wetlands.. For which we use a simple mass conservation equation for determining global water balance....
Mass conservation:
Blue Green Dream Workshop

11. Micropollutants in and after WSUD
Catchment
WSUD
Routing
Micropollutants in and after WSUD
3a. Water Quantity - Dominant vertical flow
Used for:
Infiltration Systems
- Biofilters etc.
...and ones with dominant vertical flow – including infiltration systems, biofilters etc.... It might seem a bit overloaded with different variables – but this model is again a simple mass conservation technique – where in the case of a biofilter we have three different reservoirs: ponding zone, filter and drainage zone – and for each of these zones we define state variables (ie. Ponding depth, saturation of the filter, etc) and flows which connect them, or pertain to the global water balance (ie. ET, seepage, overflow)... If we take a look at the flow connecting ponding zone and the filter, we can identify three limiting factors which influence it (unlike the model for horizontal direction, which is implicit) for this one we decided on an explicit form, so we need to place limits – flow is the critical of the three values, - what can flow (physicaly possible), whether there is enough water for it to flow (in the upper reservoir), whether there is enough space (in the lower reservoirs)
Blue Green Dream Workshop

12. Micropollutants in and after WSUD
3b. WSUD systems, Universal Stormwater Treatment Model (Wong et al. 2006)
Series of Continuous Stirred Tank Reactors
Phase 1: Mixing
Phase 2: Removal process Vo co
Qin
cin
Qout
cout = co
After we solve water quantities, we turn on the water quality. For this, we decided on concept used by chemists... Series of continuous stirred tank reactors... For those of you who are unfamiliar with these... It is a concept well used by chemical engineers to describe chemical reactions, by assuming instant and complete mixture in the reactor... Looking ie. At a sample of the pond – here devided into 4 different Cont. St.Tank Reactors, we have a first phase of mixing – with certain characteristics of the inflow water in terms of quantity and quality – then an instant and total mixture (depicted by colours) – so the next reactor receives quality of water that is identical to the quality of the first one, and so on... These series of tank reactors can in a way simulate advection and dispersion... What you would have in models which use transport equation as basis for pollutant transport....
Blue Green Dream Workshop

13. Phase 2: Compartment process modelling
Settling / resuspension
Partitioning
(slow/fast)
Volatilization
Photolysis
Hydrolysis
Aerobic/Anaerobic biodegradation
Diffusion
Qin, Pin Din
Qout, Pout Dout
Plant uptake
Straining
Water
Sediment
Particulate phase
Mechanical processes
Dissolved phase
Physical
Physico-chemical
Bio-chemical
Coming now into fate of pollutants in the treatment system... And looking at one CSTR, we can identify different processes which are inherent to two phases in which a certain pollutant can be: particulate or dissolved. Please note that I still haven’t said a word about a certain pollutant – this is a universal story – which is then refined when dealing with a particular/specific pollutant – by its inherent properties. Ie. If we take Simazine, one of the hazardous pollutants from the List of 33 priority pollutants (Simazine is a pesticide) – looking at different public databases, we identified that it can sorb well to soils which have high organic content, it is prone to biodegradation once sorbed In case of simazine, only these two processes will be of importance, and total quality would be simulated with them.
Blue Green Dream Workshop

14. Preliminary study - tracers
Water Quantity
I didn’t want to go too deep into the theme, so I decided on showing you some of the results I’ve got from our preliminary study – tracer tests. We’ve used Potassium chloride as an inert tracer in the biofiltration system at Monash University – which is a full scale system. And here on the upper two figures you can see how water quantity is simulated (on the right there is an overlap of what has been measured vs. what has been modelled... And having in mind that I used a rather simple model, I am very satisfied with the results I’ve got.
On lower figures – you can see how the water quality has been simulated – that is, concentration of Chloride ions, which again seems ok.
That is all I have prepared for you. Thank you for your attention!
Water Quality

15. Thank you!