Abstract
The effectiveness of treating effluent from a malting processing plant using bio-coagulants (Aloe vera, Cactus opuntia and Okra seeds) was determined in this study and compared to that of a chemical coagulant (Alum). In investigating effectiveness of the coagulants water quality parameters were analysed i.e. turbidity, total dissolved solids, electrical conductivity, temperature and pH. The experiments were designed using Simplex Centroid Experimental Design from MINTAB 19, which provides 10 possible blends for the three biocoagulants. The results showed that Alum was the most effective coagulant as it reduced the turbidity from 734 NTU to 68.3 NTU and Total Dissolved Solids (TDS) from 19800 ppm to 880 ppm at a dosage of 40 mg/L. Okra seeds had an optimum dosage was 35 mg/L with a turbidity and TDS removal of 88.83% and 95.25% respectively. Cactus opuntia was able to reduce electrical conductivity from 66.7 mS/m to 1.4 mS/m at a dosage of 55 mg/L. Aloe Vera had an optimum dosage of 40 mg/l with a turbidity and TDS removal of 74.25% and 95.40% respectively. For Cactus opuntia it was 50 mg/L obtaining turbidity and TDS removal of 74.66% and 95% respectively. The best blend of the biocoagulants had a ratio of (0.17, 0.17, and 0.67) for Aloe vera, Cactus opuntia and Okra seeds respectively. At a dosage of 40 mg/L the turbidity removal was 83.92% and TDS removal was 95.12%. Most of the results obtained were within the standard limits accepted by Enviromental Management Agency (EMA). It is important to blend the biocoagulants so as to increase effectiveness and to reduce the amount of each coagulant used. These results support the application of biocoagulants blends in the treatment of malting processing plant effluent.