Smart Water Treatment: Biodegradable Bio-Coagulant Hydrogel Beads

 DATE OF COMPLETION: 20/05/2026

📌 Project Overview

Goal: Replacing synthetic, expensive chemical water treatments with eco-friendly hydrogel beads made from natural biomaterials and agricultural waste.
Smart Tech: Integrated with an ESP32 microcontroller and turbidity sensor for automated visual feedback via LED indicators.
SDGs Targeted: SDG 6 (Clean Water and Sanitation), SDG 12 (Responsible Consumption & Production), SDG 13 (Climate Action).

🧪 Science & Materials Behind the Beads

Moringa Seed Powder (Moringa oleifera): Contains positively charged cationic proteins that neutralize negatively charged soil particles, causing them to form heavy flocs and drop to the bottom.
Banana & Orange Peel Powders: Natural pectin, cellulose, and carboxyl functional groups actively bind contaminants via biosorption and surface ion interactions.
Activated Charcoal: High-porosity carbon matrix designed for physical adsorption of suspended impurities.

Sodium Alginate + Calcium Chloride ($\text{CaCl}_2$): Sodium alginate acts as the encapsulating polymer matrix. Dropping the biomaterial-alginate mixture into a $\text{CaCl}_2$ solution triggers instant ionic crosslinking to form firm, biodegradable hydrogel beads.

🔬 Bead Formulation

Step 1: Raw Materials Collection – Collect moringa seeds, banana peels, orange peels, and charcoal.
Step 2: Slight De-Moisting – Wash all materials and naturally de-moisten them to remove excess moisture.
Step 3: Grinding into Fine Powders – Grind the dried materials separately into fine powders using a grinder.

Step 4: Preparing Sodium Alginate Solution – Dissolve sodium alginate in distilled water using a double-boiler setup to facilitate smooth dissolution without degrading the polymer.

*Figure 1: Double-boiler setup for dissolving sodium alginate.*

Step 5: Mixing All Powders into the Solution – Add all prepared powders into the sodium alginate solution and mix thoroughly.
Step 6: Homogeneous Mixture – Continue mixing until a smooth, uniform black slurry is obtained.
Step 7: Dripping into Calcium Chloride Solution – Transfer the slurry into a syringe and drop it carefully into a $\text{CaCl}_2$ solution.

*Figure 2: Dripping biomaterial slurry into Calcium Chloride solution using a syringe.*

Step 8: Bead Formation (Cross-Linking) – Allow calcium ions to cross-link with sodium alginate to form stable, spherical hydrogel beads. Leave them in the bath to solidify.

*Figure 3: Hydrogel beads curing inside the Calcium Chloride bath.*

Step 9: Washing – Wash the formed beads multiple times with distilled water to remove remaining impurities.
Step 10: Drying – Place the beads in a plastic petri dish and dry them completely.

*Figure 4: Synthesized hydrogel beads drying in a plastic petri dish.*

⚡ IoT Smart Sensor Setup & Qualitative Results Hardware Configuration

ESP32 Microcontroller: Processes sensor input to track water clarity in real time.
Analog Turbidity Sensor: Works on a light-scattering mechanism to detect suspended particulate density.
Status LED Output: Visual indicators wired directly to the ESP32.

Testing & Visual Outcome

Procedure: 250 mL soil-water samples were treated with equal bead doses, stirred gently for 1 minute, and left to settle for 10–15 minutes.
Observations: Rapid floc formation, visible particle settling, and significant recovery of water clarity.

Initial Contaminated Water	Treated & Clarified Water

Raw turbid sample before treatment	Clear sample after 30 mins treatment

Qualitative Indicator: Once suspended particles settled and water clarity was restored, the ESP32 triggered the status LED to switch from red to green, signaling successful purification.

Turbid Water (System Triggered)	Purified Water (Target Achieved)

Red LED active during high turbidity	Green LED active post-purification