Abubeker, Yimam (PhD)Arega, Getaneh2019-01-042023-11-102019-01-042023-11-102018-10http://etd.aau.edu.et/handle/12345678/15549Malt industries generate large amounts of wastewater effluent which contains a high concentration of biodegradable and non-biodegradable organic compounds which are poisonous to the environment and to eco system if discharged untreated. In this study, treatment performance of “Suphe” soil was evaluated first by treating composite malting waste water samples collected from different stages of production process at three different doses which were, 50mg/l, 500mg/l, 1000mg/l of “Suphe” soil in order to remove COD, BOD, TSS, then it was followed by adjusting the pH of waste water at acidic (pH 5), neutral (pH 7) and basic (pH9) medias. Sodium Hydroxide (NaOH) 0.1N and Sulfuric acid (H 2 SO 4 ) 0.1 N were used for adjusting the pH at the desired levels and the removal efficiency of “Suphe” soil was best recorded at pH of 7 and coagulant dose of 50 mg/l. Design-Expert 7.0.0 three-level-three-factor Box-Bhenken Design (BBD) was applied for experimental design and statistical analysis of results. Coagulant dose, pH of wastewater, and settling time had a significant effect on treatment process of malting wastewater samples process. For this treatment system, a set of experiments was performed to investigate removal of COD, BOD and TSS at different experimental phases. From these analyses, Results on overall efficiency had COD and BOD removal performance of 94.3% and 94.4 % for the first wet steep; 97.7%and 97.1% for the second wet steep and 96.3% and 96.1% for the composite treated effluent respectively. Andthe turbidity removal efficiency of the “Suphe” soil coagulant was 98.76%, 99% and 99.83% respectively for first wet steep, second wet steep and finally treated composite effluent at coagulant dose of 50 mg/l and pH of 7 On the other hand at the same pH level in which “suphe” soil was used, Alum turbidity removal efficiency was 96.2%, 96.6%and 99.4% respectively as mentioned above. Therefore, “Suphe” soil is found to lay a significant malting wastewater pretreatment agent which has the potential to replace the hydrated aluminum sulphate.en-USBiodegradablewastewaterSuphe‖ soilcoagulantmaltingThesis