Developing a Novel Water Filtration System using Carbon-Based Adsorbents

Laundry pollutants including Polymer-Chain-linked Metal ions (PCMs), aromatic compounds, and heavy metal ions critically threaten aquatic ecosystems. Current centralized water reclamation plants suffer from operational inefficiencies and aging infrastructure, preventing optimal pollutant removal. This study proposes a decentralized water filtration system using a gravity-based filtration column with carbon-based adsorbents. Batch extraction experiments revealed that Activated Charcoal (AC) demonstrated superior removal efficiency for both PCMs and aromatic compounds compared to other adsorbents. A gravity-driven prototype was constructed using 39mm PVC pipes with AC and sea sand. Empirical testing determined that a 9g:1.15g sand-to-AC ratio achieved optimal flow parameters while maintaining 94% removal efficiency. Sueded microfiber was identified as the optimal membrane material. Long-term testing with real-life discharge water (443ppm) showed that filters containing 5g of AC maintained effectiveness for 20 hours before dropping below 75% removal efficiency. AC demonstrated regeneration capability under weak acid washing, recovering to 97% removal efficiency after adsorption-desorption cycles, confirming prototype reusability. To address heavy metal ions, a composite polyethylenimine-Alginated-AC (PAA) adsorbent was synthesized and verified for removal efficiency across all pollutant classes. The PAA filter was integrated into a 3D printed mountable casing designed for washing machine output valve applications. This research provides promising groundwork for developing decentralized, scalable AC-based gravity-driven filters for laundry effluent treatment, offering a practical solution to current wastewater management challenges. Limitations and next steps: potential microfiber shedding from the membrane, a hydraulic mismatch versus real washing-machine discharge (≈3–5 gpm, 11–19 L/min), and the need for closed-loop handling of acid-wash effluent during adsorbent regeneration are acknowledged; we outline monitoring protocols, scale-up by empty-bed contact time (EBCT) parity, and neutralization/capture of regeneration liquor for compliant disposal.