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Coag-flocculation process was used to treat brewery effluent stream with Detarium Microcarpum seed powder (DMSP) and oyster dried shell powder (ODSP) as coagulants. The proximate analyses of the coagulants were obtained using AOAC standard method. Percentage moisture, ash, fat, crude protein, crude fiber and carbohydrate content were determined for both coagulants. Jar test experiments were employed for the coag-flocculation process and response surface methodology (RSM) optimize the process. A box-Behnken design (BBD) of Design Expert 6.0.8, implementing RSM was used to evaluate the effects and interactions of three factors: coagulant dosage, pH and stirring time on the treatment efficiency. The optimal conditions obtained were coagulant dosage of 100.53mg/L, pH of 2.001 and stirring time of 24.47mins with 90.44% solid particle (SP) removal (desirability value of 1.0) and coagulant dosage of 104.19mg/L, pH of 3.34 and stirring time of 27.54 with 96.55% SP removal (desirability value of 1.0) for DMSP and ODSP, respectively. These agree reasonably with the experimental optimum for both coagulants. A determination coefficient, R 2 , of 97 and 98%; F-value of 45.8056 and 55.3045; and prob.-value of 1.92E-07 and 2.39E-07 for DMSP and ODSP respectively were used to evaluate the model adequacy.RSM has been demonstrated to be appropriate approach for the optimization of this process.

The inhibition of copper corrosion by acid extract of Gnetum africana was studied using weight loss method of monitoring corrosion rate. The inhibition of Gnetum africana on copper corrosion was optimized by application of 2 3 factorial design. While the interactive effects of temperature, inhibition concentration and reaction time were investigated, the input factors and output response were also optimized. Optimum conditions for inhibition of Gnetum africana on copper corrosion were recorded at temperature of 303 K, reaction time of 24 h and inhibition concentration of 0.003 g/L. It could be concluded that factorial design was adequately applicable in the optimization of process variables and that Gnetuma africana sufficiently inhibited the corrosion of copper at the conditions of the experiment.

The aim of this study was to model and optimize the adsorption of Pb(II) ions from an aqueous solution using Africa elemi seed, mucuna shell and oyster shell modified with orthophosphorous acid used as adsorbents. The influence of operational parameters such as adsorbent dosage, initial pH and contact time was evaluated by response surface methodology (RSM). The interactions between the operational parameters were evaluated using Box-Behnken design of response surface methodology. The optimum conditions for maximum removal of Pb(II) ions were observed at pH of 2.0, 100 mg adsorbent dosage and 70 min of contact time, with correlation coefficient R 2 , 0.996 for Africa elemi seed adsorbent; pH of 6.0, 100 mg adsorbent dosage and 40 min contact time with R 2 0.996 for mucuna shell adsorbent; and pH of 6.0, 100 mg adsorbent dosage and contact time of 40 min for oyster shell adsorbent. The ANOVA results obtained from the RSM were analyzed using secondorder polynomial equations, and the contour plots showed the interaction among the variables of the adsorption. This shows that the prepared low-cost adsorbents can be effectively adopted for the removal of Pb(II) ions from industrial wastewaters.

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This work investigated the performance of Okra seed (Hibiscus esculentus L.) extract in removal of suspended dissolved particles from brewery effluent by coag-flocculation process at room temperature using various doses of okra seed extract. The study was carried out using nephelometric jar test. The perikinetic data generated were fitted to specific models for the determination of reaction order, rate constant, coagulation period. The maximum coag-flocculation performance is recorded at rate constant, K m of 3.6 × 10 ିଷ L (mg.min)-1 , dosage of 100 mg L -1 ; pH of 6 and coagulation period of 0.38 min while the minimum is recorded at K m of 2.95 × 10 ିହ L (mg.min)-1 , dosage of 500 mg L -1 , pH of 10 and period of 93 min. The optimum efficiency recorded at 92.6% for 30 min shows that the system is perikinetic controlled. The results indicate that okra extract can serve as a potential coagulant for the treatment of brewery effluent.

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