Electrocoagulation Dye Removal for Water Cleanup

ISEF Category: Environmental Engineering

Subcategory: Pollution Control  ·  Difficulty: Intermediate  ·  Setup: School Lab  ·  Time: 1 to 2 Months

The Hook

Textile dye pollution can leave water dark even after treatment. Your project can test a cheap cleanup method that uses electricity, not just filters. Aluminum electrodes can help clump tiny particles so they drop out of water. That gives you a clear way to measure which reactor design works best.

What Is It?

Electrocoagulation is a water treatment method that uses an electric current to help remove pollutants. In your setup, aluminum electrodes slowly release ions into the water. Those ions act like tiny magnets for dirt, dye, and fine particles. They form bigger clumps, called flocs, that are easier to remove.

Think of it like using electricity to make the mess collect itself. Instead of adding a chemical coagulant from a bottle, you make the coagulant in place from the electrodes. That makes this a strong engineering project, because you can change the reactor design and see how the cleanup changes.

For this topic, you will usually test simulated textile wastewater, which means dyed water made in a controlled way. That keeps your samples safer and more consistent than real wastewater. You can then measure how much color or cloudiness drops after treatment.

Why This Is a Good Topic

This is a good science fair topic because you can test real engineering variables, not just guess which design might work. Current density and electrode spacing both affect how fast the reactor removes dye, so you have clear independent variables. The project connects to water cleanup, industrial pollution, and low-cost treatment design. You can learn experimental design, calibration, and data analysis without needing a university lab.

Research Questions

• How does current density affect dye removal efficiency in a small aluminum electrocoagulation reactor?
• How does electrode spacing affect turbidity reduction in simulated textile wastewater?
• Does the reactor remove color more effectively at higher current density for the same starting dye concentration?
• To what extent does changing electrode spacing alter the energy used per unit of dye removed?
• Which electrode spacing gives the best balance between removal efficiency and power use?
• How does the initial turbidity level change the reactor’s cleanup performance?
• Does repeated use of the same aluminum electrodes change removal efficiency over multiple trials?

Basic Materials

• Aluminum foil or aluminum sheet electrodes.
• 9V battery or low-voltage DC power supply.
• Alligator clips with insulated leads.
• Plastic beaker or clear container.
• Digital kitchen scale with 0.1 g accuracy.
• Ruler or calipers for electrode spacing.
• Stirring rod or plastic spoon.
• Food dye or methylene blue for simulated wastewater.
• White card or printed color reference sheet.
• Smartphone camera with manual exposure control.
• Turbidity tube, Secchi-style visibility test, or homemade cloudiness comparison chart.
• Distilled or tap water.
• Safety goggles and nitrile gloves.

Advanced Materials

• Benchtop DC power supply with adjustable voltage and current readout.
• Digital multimeter for current and voltage measurements.
• Graphite or aluminum electrode variants for comparison.
• Conductivity meter.
• UV-Vis spectrophotometer or colorimeter.
• pH meter.
• Magnetic stirrer and stir bar.
• Analytical balance.
• Glass reactor cell or custom acrylic reactor.
• Filtration setup for collecting flocs.
• Turbidimeter.
• Image-based color analysis setup with fixed lighting and calibration card.

Software & Tools

• ImageJ: Measures color intensity from photos and helps you turn images into quantitative data.
• Tracker: Organizes repeated measurements and helps you compare trends across trials.
• Google Sheets: Calculates averages, standard deviation, and graphs for your reactor results.
• R or Python: Fits models and checks whether current density or spacing has a real effect.
• NIH ImageJ plugin Color Deconvolution: Separates color channels when you need cleaner image-based measurements.

Experiment Steps

1. Define the performance metric you will measure, such as color removal, turbidity reduction, or energy use per unit cleanup.
2. Choose one variable to change first, then hold the rest of the reactor design constant.
3. Plan a calibration method so your color or cloudiness signal becomes a numerical result.
4. Design controls that show whether the electric current, and not just settling, caused the cleanup.
5. Map out how you will compare electrode spacing and current density across repeated trials.
6. Decide how you will test reproducibility, including how you will handle used electrodes and fresh batches of simulated wastewater.

Common Pitfalls

• Using changing room light for photo analysis, which makes color results drift between trials.
• Letting electrodes touch or tilt, which changes the effective spacing and can short the circuit.
• Comparing samples with different starting dye levels, which hides the effect of current density.
• Ignoring electrode wear, which makes later trials look worse because the aluminum surface changed.
• Measuring only the final color and not the energy input, which misses the efficiency tradeoff that matters in reactor design.

What Makes This Competitive

A stronger project goes beyond a simple before-and-after cleanup test. You can compare efficiency against energy use, not just color change. You can also test whether one design works across several dye types or turbidity levels. Careful controls, repeated trials, and a clear statistical comparison will make your results much more convincing.

Project Variations

• Test methylene blue, food coloring, or a mixed dye solution to see whether reactor performance changes with pollutant type.
• Compare aluminum electrodes with iron electrodes to see which material gives better floc formation and color removal.
• Change the reactor geometry, such as vertical versus horizontal electrode placement, and measure how flow and bubble formation affect cleanup.

Learn More

• US EPA water treatment resources: Search the EPA site for background on coagulation, flocculation, and wastewater treatment basics.
• PubMed: Search for review articles on electrocoagulation and dye removal to find peer-reviewed summaries of the field.
• NIH PubChem: Look up dye properties such as molecular structure, solubility, and safety data.
• NOAA National Ocean Service: Read plain-language pages on water pollution, turbidity, and environmental impacts.
• MIT OpenCourseWare: Search for environmental engineering or water treatment lectures that cover coagulation and reactor design.