Abstract:
To investigate the effects of the three primary substrates on colour removal from distillery slop using anaerobic hybrid UASB. There were three experimental sets in this study. The first set comprised COD of distillery slop at 1,500 mg/l and each substrate was mixed at equal amounts. In the second set, the amounts of the substrates were doubled. These same substrates were tripled in the third set. To all of the experimental sets, wastewater was diluted from concentrated distillery slop from an anaerobic pond. The primary substrates used in each experimental set were sugar (sugar1) and soymilk. Experiment with sugar equal to the amount normally found in soy milk were also investigated as a control (sugar2). All of the experimental sets had reactors without any substrates as control units. In the first experiment, it was found that the colour removal efficiency of the reactors with sugar1, sugar2 and soy milk were 10%, 8% and 5%, respectively. While the COD removal in the corresponding reactors were 57%, 26% and 44%, respectively, the organic loading rate (OLR) 1.62, 1.15 and 1.62 kgCOD/cubic m-d, respectively. When compared with the results of the control reactor, the colour and COD removal were 0% and 14%, respectively. In the second experiment, it was found that the colour removal efficiency of the reactors with sugar1, sugar2 and soy milk were 13%, 6% and 9%, respectively; while the COD removal in the corresponding reactors were 70%, 49% and 67%, respectively. At an OLR 2.43, 1.49 and 2.43 kgCOD/cubic m-d, respectively. When compared the results of the control reactor, the colour and the COD removal were 0% and 1%, respectively. In the third experiment, it was found that the colour removal efficiency of the reactors with sugar1, sugar2 and soy milk were 13%, 11% and 15%, respectively; while the COD removal in the corresponding reactors were 76%, 60% and 78%, respectively. At an OLR 3.24, 1.83 and 3.24 kgCOD/cubic m-d, respectively. When compared with the results of the control reactor the colour and the COD removal were 0% and 5%, respectively. These results showed that the addition of substrate increased colour removal efficiency. It can be concluded that the addition of substrate will increase colour removal efficiency. No significant difference in colour removal between soy milk and sugar. Furthermore; increasing the substrate enhanced the colour removal efficiency. A higher efficiency of colour removal was observed when soy milk was added. However, a slight increase in colour removal was observed when sugar was added