| 摘要 |
<p>PURPOSE:To perform nitrification of N compds. and removal of phosphates simultaneously and to permit efficient and stable maintenance and control of operations by bringing the waste water added with Ca agents and controlled of pH and BOD amts. into contact with specific solid particles under aerobic conditions. CONSTITUTION:Waste water, Ca agents and alkali agents are put into a treating tank 1 through pipes 6, 7, 8, and pH is controlled to 7-9.5 with a pH controller 13. The waste water ascends in an inside cylinder 2 together with solid particles 4 by the effect of the air through a pipe 3, and circulating flow in an arrow direction is formed. The particles 4 are, for example, ores, bone black, etc. on which microbial membranes and hydroxyapatite can be formed. The feed rate for the waste water is controlled automatically in such a way that the volume loading quantity of BOD by a BOD detector 14 attains <=1.5kg-BOD/m<2>.day. Then the N compds. in the waste water are oxidized down to nitrate N; at the same time, phosphates react with Ca and sticking of microorganisms thereon is eliminated at all or the phosphates are removed by growing crystals of hydroxyapatite on the surfaces of a part of the particles 4.</p> |
