Effects of Chlorine Dioxide on the Bioactivity of Planktonic and Attached Bacteria Grown in Annular Reactor System

Annular reactor; Epifluorescent microscope; Adenosine triphosphate(ATP)；Chlorine dioxide; Abstract: The artificial solution, including organic molecular weight cut-off less than 5 K added indigenous bacteria taken from biofilter conducted in bench-scale experiment, was drawn by peristaltic pump pumped into Annular Reactor system (ARs) with flow rate 20 mL/min and rotating velocity of 134 rpm. ARs could reach stable at the operational time of 40 hrs. Then, chlorine dioxide was added into ARs to keep system consisting of three chlorine dioxide dosages , including 0.5, 1.0 and 1.5 mg-ClO2 as Cl2/L. Live-Dead microorganisms in this research were measured using both kinds of dye, such as CTC (5-cyano-2,3-diolyl tetrazolium chloride) and DAPI (4’,6-Diamidino-2-phenylindole dihydrochloride), observed under fluorescence microscopy having G-2A filter (EX 510-560 nm, DM 575, BA 590 nm) for CTC, and UV-2A (UV-2A (EX 330-380 nm, DM 400 nm, BA 420 NM) for DAPI. Of course, the measurement of ATP (Adenosine triphosphate) was used as another parameter to evaluate the bacterial activity. Current data shows that when initial chlorine dioxide of 0.2 mg-ClO2asCl2 /L could not effectively control the bacterial cells, especially that the remaining dosage decreased to zero at longer reaction time. In contrast with low chlorine dioxide dosage, 1.0-1.5 mg-ClO2asCl2 /L could not only control the planktonic bacteria but also inhibit the growth of respiring cell attached on the slide. Parameter using Dead-Live cells and ATP to express bacterial activity could show the similar performance while chlorine dioxide was applied into ARs.