Modelling particle transport of car tire rubber particles using HYDRUS 1D

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keneth
Posts: 6
Joined: Mon Jul 01, 2024 2:13 pm
Location: Netherlands

Modelling particle transport of car tire rubber particles using HYDRUS 1D

Post by keneth » Mon Jul 01, 2024 10:34 pm

Dear Prof Jirka,

I am currently doing my MSc thesis and I am trying to model transport of car tire particles in saturated porous media. I am running a column experiment with a homogeneous sand bed of 26 cm supported by two gravel layers of 0.25 cm at the top and bottom of the column (only the sand bed is of interest). My influent fluid is artificial rain water mixed with DOC, and my tire particles are introduced as a 3 mm uniform layer of tire-sand-induced mixture at the top of my column, followed by a small layer of sand and a final gravel layer at the very top.

I am using zinc concentrations as a proxy to do the mass balance computations, i.e., for the 400 mg of tire particles introduced at the top of the column, I want to know what part of that mass leaves my column outlet and what mass is retained. So, effluent samples are collected at the outlet, analysed for zinc concentration and then these need to be converted into mass of tire rubber at the outlet.

However, I need to fit my experimental data into HYDRUS using inverse solution approach and understand the transport mechanisms of these particles inside my column. I ran a conservative tracer experiment and used HYDRUS to estimate some initial parameters like dispersivity and assess the packing of the column.

1. Do I use this same value of dispersivity in my subsequent modelling? Or this value is only applicable to my conservative tracer?
2. Which non-equilibrium solute transport model should I use?
3. What would be my upper and lower solute boundary conditions for my system? (this was easy for the tracer but a bit difficult to figure out for the tire particles.)
4. How do I eventually model this transport of these particles in my column since I am introducing them at the top of my column?

I look forward for your help

Thank you!
Attachments
Observation_Node.PNG
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Jirka
Posts: 6074
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Modelling particle transport of car tire rubber particles using HYDRUS 1D

Post by Jirka » Tue Jul 02, 2024 7:31 am

The next two weeks, I’m on vacation, traveling in Europe, and I will not have time to answer questions in the discussion forum. J.

keneth
Posts: 6
Joined: Mon Jul 01, 2024 2:13 pm
Location: Netherlands

Re: Modelling particle transport of car tire rubber particles using HYDRUS 1D

Post by keneth » Tue Jul 02, 2024 9:24 am

Dear all,

Since Prof. Jirka is on vacation, I would like to seek some assistance from anyone about some of the questions below. I will appreciate any assistance accorded.

I am currently doing my MSc thesis and I am trying to model transport of car tire particles in saturated porous media. I am running a column experiment with a homogeneous sand bed of 26 cm supported by two gravel layers of 0.25 cm at the top and bottom of the column (only the sand bed is of interest). My influent fluid is artificial rain water mixed with DOC, and my tire particles are introduced as a 3 mm uniform layer of tire-sand-induced mixture at the top of my column, followed by a small layer of sand and a final gravel layer at the very top.

I am using zinc concentrations as a proxy to do the mass balance computations, i.e., for the 400 mg of tire particles introduced at the top of the column, I want to know what part of that mass leaves my column outlet and what mass is retained. So, effluent samples are collected at the outlet, analysed for zinc concentration and then these need to be converted into mass of tire rubber at the outlet.

However, I need to fit my experimental data into HYDRUS using inverse solution approach and understand the transport mechanisms of these particles inside my column. I ran a conservative tracer experiment and used HYDRUS to estimate some initial parameters like dispersivity and assess the packing of the column.

1. Do I use this same value of dispersivity in my subsequent modelling? Or this value is only applicable to my conservative tracer?
2. Which non-equilibrium solute transport model should I use?
3. What would be my upper and lower solute boundary conditions for my system? (this was easy for the tracer but a bit difficult to figure out for the tire particles.)
4. How do I eventually model this transport of these particles in my column since I am introducing them at the top of my column?

I look forward for your help

Thank you!

Jirka
Posts: 6074
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Modelling particle transport of car tire rubber particles using HYDRUS 1D

Post by Jirka » Wed Jul 03, 2024 8:09 am

Your questions:
1. Yes.
2. Two Kinetic Sites Model (particle transport).
3. There is plenty of guidance on the HYDRUS website on how to do this. See, for example:
https://www.pc-progress.com/en/Default. ... b-bacteria
https://www.pc-progress.com/en/Default. ... -nanotubes
and many references. J.

keneth
Posts: 6
Joined: Mon Jul 01, 2024 2:13 pm
Location: Netherlands

Re: Modelling particle transport of car tire rubber particles using HYDRUS 1D

Post by keneth » Wed Jul 03, 2024 11:56 pm

Thanks a bunch, Prof Jirka. I have gone through the materials you attached, and they've been resourceful moreso the MWCNT transport experiment. However, just one more last question;

So, I am not flushing my particles into the column as a suspension (due to hydrophobicity and aggregation) but rather have these as a small layer approximately 0.3mm thickness (rubber-sand mixture) packed near the top of my column (See attached photo).

1. Do I define my upper BC as a Stagnant BC for volatile solutes? If so, when I check in the 'help' section of HYDRUS, one would have to specify the 'concentration above this layer.' What does that mean?

2. Finally, would the initial solute conditions, for my case be the second option i.e., In Total Concentrations [Mass_solute/Volume_soil]?

Thanks once again and apologies for asking these whilst you are on your vacation.

Cheers!
Attachments
Image 04-07-2024 at 01.50.jpeg
Image 04-07-2024 at 01.50.jpeg (419.88 KiB) Viewed 170 times

Jirka
Posts: 6074
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Modelling particle transport of car tire rubber particles using HYDRUS 1D

Post by Jirka » Thu Jul 04, 2024 7:16 am

Based on your description, the particles are initially in the soil column, and they should therefore be introduced via initial conditions, and not via boundary conditions. It certainly makes no sense to use “volatile BC”, which is intended for volatile solutes, such as fumigants, carbon dioxide, oxygen, etc.

Initial conditions: that depends on what information you have available. I guess, total concentration is the best option.
J.

keneth
Posts: 6
Joined: Mon Jul 01, 2024 2:13 pm
Location: Netherlands

Re: Modelling particle transport of car tire rubber particles using HYDRUS 1D

Post by keneth » Thu Jul 04, 2024 12:46 pm

Thank you, Prof. Jirka!

keneth
Posts: 6
Joined: Mon Jul 01, 2024 2:13 pm
Location: Netherlands

Re: Modelling particle transport of car tire rubber particles using HYDRUS 1D

Post by keneth » Sun Jul 07, 2024 11:26 pm

Hello,

So, apparently I am trying to use the the two kinetic sites model to fit my experimental data. For some reasons, I am not getting a fit.
I have attached my HYDRUS 1D file just for a quick perusal. I have viewed some literature but I still cannot fit my experimental data.

I will really appreciate any help that will be accorded.
Attachments
Tire-Particle transport modelling.zip
(52.95 KiB) Downloaded 4 times
two kinetic site.PNG
two kinetic site.PNG (56.34 KiB) Viewed 84 times

keneth
Posts: 6
Joined: Mon Jul 01, 2024 2:13 pm
Location: Netherlands

Re: Modelling particle transport of car tire rubber particles using HYDRUS 1D

Post by keneth » Wed Jul 10, 2024 7:59 am

Hello folks, I am kindly requesting your assistance with this problem.
Thank you.
keneth wrote:
Sun Jul 07, 2024 11:26 pm
Hello,

So, apparently I am trying to use the the two kinetic sites model to fit my experimental data. For some reasons, I am not getting a fit.
I have attached my HYDRUS 1D file just for a quick perusal. I have viewed some literature but I still cannot fit my experimental data.

I will really appreciate any help that will be accorded.

Jirka
Posts: 6074
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Modelling particle transport of car tire rubber particles using HYDRUS 1D

Post by Jirka » Wed Jul 10, 2024 11:04 am

I'm on vacation. Greetings from Budapest. J.

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