Characterization of Constituents of Soluble Microbial Products in Wastewater Treatment Processes

1995 Fiscal Year Final Research Report Summary

• Project/Area Number: 06650614
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Civil and environmental engineering
• Research Institution: Nagaoka College of Technology
• Principal Investigator: TANAKA Kazuhiro Nagaoka College of Technology, Dept. of Civil Engineering, Research Associate, 環境都市工学科, 助手 (40259841)
• Co-Investigator(Kenkyū-buntansha): ARAKI Nobuo Nagaoka College of Technology, Dept. of Civil Engineering, Associate Professor, 環境都市工学科, 助教授 (30193072)
• Project Period (FY): 1994 – 1995
• Keywords: Soluble Microbial Products (SMP) / Waste Water Treatment / Gel Chromatography / Molecular Weight Distributions

Research Abstract

Soluble microbial products (SMP) were investigated by employing phenol degrading bacteria and two types of reactors, i. e., chemostat reactors, which were operated in parallel at three different hydraulic retention times, and a biofilm reactor. Constituents of SMP sampled from each reactor were fractionated by two types of gel-chromatography in series, which one was for low molecular distributions while other one was for high molecular distributions. At a retention time of 0.5 days, SMP accumulated 18% in comparison with that of the influents COD.For longer retention time, as high as 8 days, the SMP concentration remained 15% on the influent. The gel-chromatography distinguished three constituents from SMP sampled from phenol-degrading chemostats. Most higher molecular portion of those contained polysaccharides in high level more than the other two constituents, which produced in relatively lower retention times. Second constituent was major component for total SMP, which composed of unsaturated compounds such as DNA and RNA, that increased the concentration of those with a degrease in the retention time. Most lower constituent consisted of proteins, which was observed at conditions only lower retention time. SMP derived from the biofilm reactor also consisted of three constituents, similarly to those from chemostats, However the fractionation pattern of SMP taken from the biofilm reactor was similar to that of chemostat at a retention time of 2 days in spite of the retention time of the biofilm reactor was 0.5 days. High biomass retention as biofilms caused the production of unsaturated compounds due to the autolysis of cells.