| 摘要 |
<p>PURPOSE:To prevent the blocking of the gap between pieces of a filler and to suppress the lowering of the efficiency of removal of ammonia nitrogen even in the winter by covering the top of a treating vessel contg. the filler with a green transparent light shielding plate to regulate the wavelength of light entering the vessel. CONSTITUTION:When raw water for tap water is subjected to surface biological treatment as pretreatment, the water 1 to be treated is treated with microorganisms sticking to the surface of a filler 3 during moving through the filler 3 packed into a treating vessel 2. At this time, an aerating pipe 4 is set in the lower part of the vessel 2 and the top opening 2a of the vessel 2 is covered with a green transparent light shielding plate 6. Since the generation of green algae can be inhibited, the blocking of the gap between pieces of the filler 3 is prevented. The efficiency of removal of ammonia nitrogen is not lowered even in the winter in which the activity of microorganisms is low.</p> |
