내부반송이 생선폐기물 처리용 소화조의 운전효율에 미치는 영향 = The Effect of Internal Recrculation on Performance of Anaerobc Digester Treating Fish Offal

다국어 초록 (Multilingual Abstract)

The effect of internal recirculation on digester performance is evaluated using reactors having 6.4cm diameter and 3cm diameter at the same surface area/reactor volume ratio.
As organic loading rate of 6kg COD/㎥·d has applied to the reactors having 6.4cm diameter, COD removal efficiency of 89.6% is achieved in the reactor operated with internal recirculation, while COD removal efficiency of 20.6% is only achieved in the reactor operated without internal reciculation. It is evident that reactor performance is dependent to internal recirculation in reactor having 6.4cm diameter. In the contrary, there is no difference in COD removal effieicency depending on internal reciculation when the same experiment is conducted using reactors having 3cm diameter. that is, more than 90% of COD removal efficiency is achieved in reactor having 3cm diameter regardless of internal recirculation.
The reason why the effect of internal recirculation on reactor performance is different depending on the reactor diameter can be explained that sufficient fluidization by evolving gas bubble can be achieved in the reactor having 3cm diameter, while sufficient fluidization can not be achieved only by evolving gas bubble in the reactor having 6.4cm diameter when the reactors were operated without internal recirculation. Internal recirculation can provide favorable condition for sludge bed fluidization. It can be seem that sludgy bed fluidization is key factor in start-up of upflow reactor. Internal reciculation also enhance microbial retaining capacity of upflow reactor. This can be confirmed through TSS and VSS assay too.