Petrochemical wastewater represents a major environmental challenge in Canada due to its complex composition, slow sedimentation behavior, and high toxicity—mainly attributed to naphthenic acids (NAs) and recalcitrant organic compounds. This study explores an innovative flocculation strategy combining synthetic polyacrylamides (PAM) with iron-grafted cellulose fibers to enhance treatment efficiency. The fibers, derived from recycled paper, offer a lowcost and environmentally friendly alternative to conventional reagents. Jar tests were conducted using different types of PAMs (cationic and anionic), alone or in combination with grafted and non-grafted fibers. The results show that iron-grafted fibers significantly improve pollutant removal through enhanced adsorption and bridging mechanisms. The best performance was obtained with 200 mg/L of grafted fibers and 1–2 mg/L of cationic PAM (particularly c-PAM 3), achieving up to 66 % removal of NAs and total organic carbon (TOC), with residual turbidity below 2 NTU.
An optimal polymer-to-fiber ratio was shown to be crucial to avoid overdosing effects, such as floc restabilization. Grafted fibers also produced more robust flocs, improving sludge dewatering and reducing downstream operational costs. Preliminary tests on other wastewater types (e.g., hydrocarbon-laden water, leachate, compost, and agro-industrial effluents) highlight the broader potential of this approach. These promising results support future work at the doctoral level to generalize its application to a wider range of industrial effluents.
In addition, a compact three-in-one reactor was developed and published in npj Clean Water (2025, IF = 12.3), integrating flocculation, solid-liquid separation, and sludge dewatering in a single unit using bridging fibers. A second paper evaluating this technology on petrochemical wastewater is currently in preparation. Overall, this approach offers a sustainable, costeffective solution for advanced treatment of petrochemical effluents and holds strong potential for industrial-scale integration.
| Date | 28 Jul 2025 |
|---|
| Original language | French |
|---|
| Awarding Institution | - École de technologie supérieure
|
|---|
| Supervisor | Mathieu Lapointe (Supervisor) |
|---|
Mebarki, M. (Author),
Lapointe (Supervisor),
28 Jul 2025Student thesis: Master's thesis › Master in Engineering: Environmental Engineering