Advantages of Psychrophiles in Improving Bio-Treatment Efficiency of Small Size Constructed Wetlands During Cold Weather

Constructed wetland technique for waste water treatment has many advantages, including high treatment efficiency, low investment and energy cost, and easy operation and maintenance However, the inhibitive effect of low temperature on treatment efficiency remains a serious problem. in cold weather for many small size wetlands. In this study, the application of cold-tolerating bacteria in maintaining the nitrogen waste treatment efficiency of small size constructed wetland during cold weather was investigated in Hebei province, northern China. Three strains of cold-resistant bacteria were purified, and their physiological characteristics in terms of growth rate and generation time under different growth conditions were tested. The effects of various environmental factors on the growth of these strains were also investigated, including ambient temperature, dissolved oxygen, carbon concentration, bio-retention time and pH. These strains of purified bacteria were then applied to constructed wetland systems, and their effects on nitrogen removal in cold temperatures were measured It was found that these bacteria strains significantly improved the nitrogen removal efficiency of the constructed wetlands, suggesting a promising role That these microorganisms play in improving the efficiency of small size constructed wetlands in waste water treatment in cold weather. (C) 2009 American Institute of Chemical Engineers Environ Prog, 29: 25-33, 2010