염료 분해균 증대를 통한 Pilot Plant에서의 담체 내 미생물 생태와 색도처리에 미치는 영향

Abstract

In a pilot-scale dyeing wastewater treatment using two-type fluidizing media, each thickness of biofilm was 15 and 30 <TEX>${\mu}m$</TEX>, respectively. The numbers of protozoa inhabited in small-size (PEMT A) and big-size (PEMT B) media were <TEX>$7.5{\times}10^4$</TEX> and <TEX>$1.25{\times}10^5$</TEX> cells/ml, respectively, and dominant species were Entosiphon sulcatus var sulcatus in PEMT A and Chlamydomonas reinhardtii in PEMT B, respectively. Flask experiments using the two media revealed that the percentages of color removal were 25.8% in PEMT A and 27.1% in PEMT B after 72-h cultivation, indicating the necessity of bioaugmentation. Experiments for bioaugmentation effect on color removal were carried out in the pilot-scale treatment for 75 d by three-step operation under the control of wastewater loading rate and microbial input rate. Dye degradation occurred mainly in the second reaction tank, and the attachment of augmented dye-degrading microorganisms to media took at least 35 d. Final value of chromaticity in effluent was 227, meeting the required standard. Therefore bioaugmentation onto media was good for color treatment. In summary, thickness of biofilm formed on the media depended upon the size of media, resulting in different ecosystem inside the media. Hence, this affected microbial community and color treatment further. Accordingly, the reduction of operation cost is expected by efficient color-treatment process using bioaugmented media.