Remediation of chemical and biochemical oxygen demand in untreated abattoir effluent using a locally engineered bio-based adsorbent

Treating high-strength abattoir effluent remains a critical environmental and public health challenge. This study evaluates the efficacy of P-32 Powdered Activated Carbon (PAC), a locally engineered bio-based adsorbent, in remediating chemical oxygen demand (COD) and biochemical oxygen demand (BOD 5 ) in effluent from the Kumasi Abattoir Ghana (KAG). Standard methods were used in sample collection and analysis. Batch adsorption studies were conducted using varying masses (5–25 g) of P-32 PAC/L of effluent. The research hypothesis that P-32 PAC will effectively remediate COD and BOD5 5 in KAG’s effluent was tested using a paired-samples t-test. Adsorbent-adsorbate interactions were investigated using linear and nonlinear adsorption isotherms. Polynomial and modified exponential decay models (mEDM) were used to predict P-32 PAC’s dosage required to remediate COD and BOD 5 to achieve regulatory limits. The findings revealed worrisome pollution levels (COD: 6613.33 ± 46.19 mg/L, BOD 5 : 1832.28 ± 28.57 mg/L). The biodegradability index (BI = 0.28 ± 0.01) indicated limited potential for biological treatment, necessitating physical-chemical remediation. Applying P-32 PAC reduced 69.4% and 73.7% of the total COD and BOD 5 , respectively, at 25 g/L ( p = 0.0014; Cohen’s d > 2.9), rejecting the null hypothesis. The linear Langmuir and the Freundlich models described COD and BOD 5 behavior, respectively. The polynomial predictive model demonstrated superior fit (RMSE: COD = 85.50, BOD 5 = 24.73), estimating optimal masses of 34.07 g/L (COD) and 28.12 g/L (BOD 5 ). These findings support P-32 PAC as an effective, eco-friendly adsorbent for high-strength abattoir effluent treatment, with implications for scalable wastewater solutions in resource-limited settings.