Abstract—The excess activated sludge production is the main problem of activated sludge method in waste water treatment plants. Several researches are being carried out to control the excess sludge production. Sludge growth process is a major factor to control the sludge production. Several observations are carried out to learn the information of sludge growth under several circumstances. One of the process was to observe the effect of light on sludge production performed by other researchers. Recently, the light emitting diode (LED) illumination is being used in different purposes including vegetable plantation. Here, we have observed sludge growth under LED illumination process with aerobic SBR plants. The white, blue and red LED illumination (each of 2 types) were used and the activated sludge growth and their waste water treatment abilities were investigated. We did not find any difference in pH, chemical oxygen demand (COD) removal in the activated sludge under LED illumination. But significant differences were found in sludge growth and sedimentation properties of activated sludge. Floc construction was disturbed by red/ blue LED illumination. It degraded the SV30 characteristics of the activated sludge. We have found that the growth of activated sludge was effected due to the different frequencies of LED illumination.

Index Terms—Activated sludge growth, COD removal, LED illumination, sedimentation

M. Kabir, R. Miura and M. Suzuki are with the Department of Electrical and Electronic Engineering, Graduate School of Engineering and Resource Science, Akita University, 1-1, Tegata Gakuenmachi, Akita-shi, Akita 010-8502, Japan (e-mail: kabir@ ipc.akita-u.ac.jp).
N. Yoshimura is with Akita University, 1-1, Tegata Gakuenmachi, Akita-shi, Akita 010-8502, Japan.

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Cite: Mahmudul Kabir, Ryutaro Miura, Masafumi Suzuki, and Noboru Yoshimura, "Activated Sludge Growth under LED Illumination," International Journal of Environmental Science and Development vol. 3, no. 6, pp. 533-538, 2012.