Detoxification of potentially eutrophic substances using P-32 powdered activated carbon

Detoxification of potentially eutrophic substances (PESs), specifically nitrate ( $${NO}_{3}^{ -}$$ ) and phosphate ( $${PO}_{4}^{ 3-}$$ ), in the Kumasi Abattoir Ghana (KAG) effluent by P-32 Powdered Activated Carbon (PAC) was investigated. The ex-ante eutrophic status ( $${NO}_{3}^{ -}$$ , $${PO}_{4}^{ 3-}$$ , and nutrient pollution index (NPI)) was explored using standard methods. A paired sample t-test was used to investigate PES percent removal (% R) based on an incremental mass of 5.00 g of adsorbent/L of the effluent. Analysis of Variance (ANOVA) was used to evaluate the significance of the adsorbent dosage efficacies. Ex-post evaluations involved adsorption studies using three isotherm models─ Langmuir, Freundlich, and Elovich. Exponential regression model (ERM) and modified exponential decay model (EDM) were used to predict the AC dosage needed to achieve environmental compliance. High ex-ante $${NO}_{3}^{ -}$$ (260.33 ± 0.31 mg/L), $${PO}_{4}^{ 3-}$$ (165.20 ± 0.61 mg/L), and NPI (38.25) suggested hypereutrophic potential. Ex-post evaluations revealed that the lowest (highest) % R for $${NO}_{3}^{ -}$$ and $${PO}_{4}^{ 3-}$$ was 25.15% (79.55%) and 44.68% (89.19%) at 5.00 g/L (25.00 g/L), respectively. The t-test revealed a significantly higher % R for $${PO}_{4}^{ 3-}$$ than $${NO}_{3}^{ -}$$ . The ANOVA findings significantly depicted increasing % R with increasing AC dosages. Langmuir and Freundlich models better explained $${NO}_{3}^{ -}$$ and $${PO}_{4}^{ 3-}$$ adsorptions, respectively. The ERM and EDM models monotonically predicted the attainment of environmental compliance at 50.00 g/L. While the study holds significant implications for effectively managing nutrient pollution, the predictive models contribute to optimizing pollution mitigation strategies by identifying the most efficient treatment dosages.