曝气对重污染河道底泥吸收和持留磷的影响

Effect of aeration on phosphorus adsorption and immobilization by sediment in heavily polluted canal

以城市重污染河道底泥和上覆水为材料,研究了底泥扰动条件下,曝气量对底泥吸收和持留水体磷的影响。结果表明,较高曝气量(3 m3.d-1)情况下,水体溶解氧和溶解性磷酸盐(SRP)含量均高于较低曝气量(0.25 m3.d-1),而pH值则相反。较低曝气量导致底泥对外源磷的吸收量是较高曝气量时的1.4倍。底泥吸收外源磷之后,较高曝气量情况下底泥的磷释放量是较低曝气量时的2.39倍。磷形态分析表明,加入的外源磷超过80%被结合到铁结合态磷中,但在较高曝气量条件下形成的非闭蓄态铁结合态磷显著高于较低曝气量。这说明与较高曝气量相比较,低曝气量更有利于底泥对水体磷的吸收和内源磷的固定。

The effect of aeration amount on phosphorus（P） adsorption and immobilization by sediment was investigated in laboratory experiments under sediment resuspension conditions.The sediments and waters used were taken from an inner-city heavily polluted canal.The results show that the concentrations of dissolved oxygen（DO） and soluble reactive P（SRP） in the overlying water under high aeration amount condition（3 m3·d-1） were higher than those under low aeration amount condition（0.25 m3·d-1）,but pH values were adverse.The amount of external P adsorbed under low aeration amount condition was 1.4 times as much as that under high aeration amount condition.The release of P,from the sediments after external P adsorption,under high aeration amount condition was 2.39 times as much as that under low aeration amount condition.P fractionations indicated that most of external P（over 80%） incorporated into sediments was accounted for in the BD-P.However,the concentration of non-occluded BD-P under high aeration amount condition was higher than that under low aeration amount condition.It is suggested that low aeration amount facilitates P adsorption and immobilization by resuspeded sediments,compared with high aeration amount.