Agricultural waste as a sustainable solution for polluted water treatment: Evaluating hybrid bio-adsorbents in the Niger Delta

Abstract

The Niger Delta, rich in oil and gas, faces severe environmental degradation largely due to oil exploration. Produced water (PW), a byproduct of oil extraction, contains harmful pollutants like heavy metals, hydrocarbons, salts, and organic contaminants, threatening ecosystems and public health. Current treatment methods are often expensive and unsustainable for local use. This study investigates the potential of hybrid activated carbon (HAAC) derived from hamburger seed coats and avocado peels as a cost-effective, sustainable alternative for PW treatment. The agricultural wastes were cleaned, carbonized, and activated with zinc chloride (ZnCl₂ ) under varying concentrations and thermal conditions. Iodine adsorption tests guided the optimization of activation parameters. A fixed-bed column experiment evaluated the adsorption efficiency, and physicochemical properties of PW before and after treatment including pH, turbidity, BOD, COD, heavy metals, and TDS were analyzed using APHA and ASTM methods. Results identified 1.5 mol/dm³ ZnCl₂ as the optimal activation level, yielding the highest iodine value (21.40 mg/kg). HAAC demonstrated superior removal of turbidity, BOD, COD, and metals compared to commercial activated carbon (CAC). Though some parameters like EC and TDS remained above limits, most improved significantly, meeting EGASPIN and DPR standards. The study concludes that HAAC is a viable, low-cost solution for PW remediation, and recommends its adoption to support environmental sustainability and job creation in oil-producing regions.