Quantitatively clarifying bio-chemical water quality dynamics as affected by anaerobic microorganisms such as denitrifying bacteria, iron-reducing bacteria and sulfate-reducing bacteria plays an important role in understanding the mechanism of water environment deterioration that accompanies organic pollution. Accordingly, beaker-scale laboratory experiments were conducted in order to obtain basic knowledge concerning water quality dynamics such as ORP, nutrient salts, sulfides, and so on, near bed material under anoxic conditions. Assuming that denitrification initially caused by anaerobic respiration impacts the reduction half-reactions that later occur in phases, the purpose of this research was as follows: based on the impact of the concentration of nitrate (NO3-N) at the point when an anoxic state was reached with the increase of phosphate (PO4-P), ammonium (NH4-N), and sulfides under anaerobic conditions, their water quality dynamics were quantitatively assessed in relation to change over time of ORP. As a result, the dynamic properties of ORP under anaerobic conditions could be characterized in five steps, suggesting that the rate of decrease of ORP at each step is influenced by the initial NO3-N content, and the higher the initial NO3-N concentration, the longer ORP took to reach equilibrium of the minimized electric potential. Also, the characteristics of increases in PO4-P, NH4-N, sulfides, and DOC can be explained in relation to the transition between ORP steps, and that their water quality dynamics were modeled with either linear or non-linear regressions. Thus, it was concluded that we were able to estimate the dynamics of PO4-P, NH4-N, sulfide and DOC conveniently through monitoring of ORP while considering the influenced of initial NO3-N levels on theses water quality items.
抄録全体を表示