This paper may be helpfull

Bouguerra, W., Barhoumi, A., Ibrahim, N., Brahmi, K., Aloui, L., & Hamrouni, B. (2015). Optimization of the electrocoagulation process for the removal of lead from water using aluminium as electrode material. Desalination and Water Treatment, 56(10), 2672-2681.

This paper may be helpfull

Bouguerra, W., Barhoumi, A., Ibrahim, N., Brahmi, K., Aloui, L., & Hamrouni, B. (2015). Optimization of the electrocoagulation process for the removal of lead from water using aluminium as electrode material. Desalination and Water Treatment, 56(10), 2672-2681.

Please give some details of your experiment.

What is the difference between repeated values?

One of the situations where wastewater initial COD values are not close to each other is to get different results under the same operational conditions.

this happened to me too, can you tell us about the details of your experimental conditions and system for further assistance?

Thanks for the inputs....I went through the paper suggested by Mr. Khaled but I am keeping all operating parameters (which discussed in paper) constant and still not getting similar results.

For more clarity about the experiment:

I carried out EC experiment on landfill leachate. I tried different electrodes and other operating conditions to see where the good results in COD reduction are achieved.

After preliminary experimentation, I thought to repeat the experiments (before putting it in research paper) where good results (>70% reduction) were observed... but now none of the result is in comparable range. For example I got more than 70% reduction in COD using SS electrode but now I am not getting more 20-25% reduction. all other operating conditions like, current, voltage, electrode dimensions, inter electrode distance and pH were kept same as previous experiments.

I tried to repeat experiments using GI electrodes too, but same story.

In any case I am not able to get more than 20-25% reduction. During last 15-20 days none of experiment is giving good result.

Now I am totally confused that how to move further...

Where I have gone wrong.

I would like to draw attention to some points you may have missed.

1- Check the connection of the electrodes to the power supply. If there is non-contact in the connections, you may see a different value than the voltage you see in constant current in your previous experiments. this affects cod removal efficiency

2- There may be impermeable film on the surface of the electrodes. suggestion clean your electrodes

3- The composition of wastewater may have changed over time. you should take the wastewater into the reactor with the same method. for example, if you treat wastewater with COD of 20000 mg / L and wastewater with COD of 5000 mg / L, the results can be 20% and 80%, respectively. Pay attention to the initial COD concentrations of your wastewater.

Wastewater characteristics could be an important variable. It’s not just limited to COD, but other parameters like electrolyte concentration and type could make substantial difference

i agree prof. mohamed Hasnain Isa.

I had the same situation. In an experiment, wastewater samples taken from the same place at different times, the TSS concentration was 500 mg / L, the COD removal efficiency was 90%, and another experiment where the TSS concentration was 3000 mg / L, the COD removal efficiency was 60% under the same conditions. As the TSS concentration increases, the potential difference in the system increases and the removal efficiency decreases at the same current intensity. there are many parameters that affect system efficiency. such as pH and electrical conductivity.

Dilara Ozturk Mohamed Hasnain Isa Khaled Khleifat

Thanks for the inputs

I am working on other parameters also now

My concern is that if I report previous results...will it be questionable. As other researcher may not get those results.

Also to update you all...after clearing the rusting on electrical connection, some improvement is observed (upto 50%) but still far away from previous one.

I'm glad you made some improvements and improvements.

In this respect, I recommend that you deal with all parameters meticulously.

I hope you'll get better.

Leachate characteristics will influence treatment outcomes. perhaps either parameter may influence a particular result obtained by electrocoagulation. Try to relate the parameters in justifying your results. From experience, repeatability in leachate treatment processes is very difficult.