| Abstract |
| Livestock wastewater is a kind of high-concentrated organic wastewater, so it is treated by anaerobic digestion process because treating by aerobic has a lot of restrictions from technical aspect. Anaerobic process is possible to decompose the organic matters and this process generate end product a little. Futhermore, it can remove intestinal parasites and produces the bio-gas which contains methane. But anaerobic process is difficult to operate because of low temperature in the field. Therefore, to operate anaerobic process in the field, autothermal aerobic digestion has to be applied to transfer a heat. The object of study is to research treatment efficiencies, the operation property and energy conversion to bio-gas by A3(Autothermal Anaerobic-Aerobic) digestion process. Experiments were conducted by operating conditions according to HRT. It was set to HRT 7days, HRT 10days and HRT 15days because of amount of influent. Results are summarized as follows: pH according to HRT is maintained the sustainable standard because of enough alkalinity. BOD concentration was sharply decreased, so the organic matters which was able to be decomposed by biological methods was removed. Temperature in the aerobic reactor was increased about 9~10℃ comparing to the influent temperature of 15℃ following the decrease of BOD concentration and the anaerobic reactor was operated by heat transfer from the autothermal process. The most effective TCOD removal efficiency was measured in the HRT 15days and SCOD was not depended on HRT. It was because of maintenance of metanogen. As the result of measures for the amount of difference between TCOD and SCOD concentration, it is judged that they have correlation with each other because variation of each removed amount according to HRT is similar with those of SS concentration. TVFAs concentration was measured about 870~2,400mg/L, but pH decline was not checked because of enough alkalinity and TVFAs/Alkalinity ratio was included in the range of 0.1~0.2. The gas production was very stable and the methane content was 65~70%. Gas production in HRT 10days was the most high and methane yield as CODrem was the most efficient in HRT 15days. |
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| Key Words |
| Pig manure, Autothermal , Anaerobic, Aerobic, Bio-gas |
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