微孔曝气与覆盖对城市重污染河道底泥磷形态分布及释放过程的影响  

Effects of fine bubble aeration and capping on the distributions of phosphorus forms and release potential in the sediment from a heavily polluted urban river

作　　者：杨长明[1] 荆亚超 沈烁[1] 徐琛[1] 

机构地区：[1]同济大学,长江水环境教育部重点实验室,上海200092

出　　处：《环境化学》2015年第6期1150-1157,共8页Environmental Chemistry

基　　金：国家水体污染控制与治理科技重大专项(2011ZX07303-001和2011ZX07303-002)资助

摘　　要：采用自行研发的泥-水界面微孔曝气系统,开展了底泥表面曝气和覆盖对城市重污染河道底泥磷释放及形态分布规律的影响研究.结果表明,微孔曝气能够有效提高上覆水的溶解氧(DO)和沉积物的氧化还原电位(Eh),能够将泥-水界面Eh维持在-100 m V左右,DO提高到6 mg·L-1以上.与对照比较,原位覆盖处理的上覆水DO和Eh有一定提高,但仍明显低于微孔曝气处理.与对照相比较,微孔曝气处理均有效降低上覆水中总磷(TP)和溶解性正磷酸盐(PO3-4)的含量.试验结束时,微孔曝气(A)和微孔曝气+原位覆盖处理(A+C)上覆水中TP含量由初始的0.201 mg·L-1分别降至0.062 mg·L-1和0.050 mg·L-1;上覆水中PO3-4含量由0.086 mg·L-1和0.078 mg·L-1分别降至0.026 mg·L-1和0.023 mg·L-1.与对照相比,微孔曝气处理明显降低了底泥间隙水中TP的浓度,在整个培养期间,其TP含量平均下降38.8%(A)和47.9%(A+C).底泥原位覆盖处理对抑制泥-水界面磷释放能力要弱于微孔曝气处理,而且在试验后期(50 d),上覆水中TP和PO3-4的含量均有所反弹.不管有无覆盖,泥-水界面微孔曝气处理均显著改变了表层底泥磷形态分布特征,显著降低了底泥中铁铝结合态磷(Fe/Al-P)组分比例,而钙结合态磷(Ca-P)含量比例却出现明显增加.单一的表面覆盖处理对底泥磷形态分布特征没有显著影响(P>0.05).研究表明,与单一的处理效果相比较,泥-水界面纳米微孔曝气处理,并结合底泥原位覆盖,更有利于抑制城市重污染河道泥-水界面中磷的释放风险.A simulation experiment with precision oxygen distribution system was conducted to study the effect of fine bubble aeration and capping on sediment-water interface on species distributions and release potential of phosphorus in the sediment sampled from a heavily polluted urban river in Hefei City,Anhui Province. The results showed that the concentration of dissolved oxygen（ DO） in the overlying water and the redox potential（ Eh） of the sediment-water interface had been significantly increased with the use of the bubble aeration device and were maintained at about 6 mg·L- 1and-100 m V respectively. Compared with the control,the capping treatment increase the Eh and DO of sediment-water interface,but the effectiveness was significantly lower relative to bubble aerationtreatments. The treatments with bubble aeration had positive effects in reducing the concentration of total phosphorus（ TP） and dissolved orthophosphate（ PO3-4） in overlying water. At the end of the experiment,the concentrations of TP in overlying water dropped from 0. 201 mg·L- 1to 0. 062 mg·L- 1for single bubble aeration（ A） and 0. 050 mg·L- 1for bubble aeration with capping treatment（ A ＋C）,and PO3-4from 0. 086 mg·L- 1and 0. 078 mg·L- 1to 0. 026 mg·L- 1（ A） and 0. 023 mg·L- 1（ A ＋C）,respectively. Compared with the control,the aeration treatments significantly decreased the concentration of TP with an average reduction of 38. 8% for A treatment and 47. 9% for A ＋ C treatment during the experiment,respectively. Although capping treatment（ C） inhibited the release potential of phosphorus in sediment-water interface as compared with the control,the inhibitory efficiency was significantly weaker relative to the fine bubble aeration treatments. Even at the end of the experiment,the concentrations of TP and PO3-4in the overlying water for capping treatment rebounded. Regardless of capping or not,the fine bubble aeration on sediment-water interface significantly changed the distribution of phosphorus speci

关 键 词：城市重污染河道 泥-水界面 纳米微孔曝气 原位覆盖 磷形态 释放过程. 

分 类 号：X52[环境科学与工程—环境工程]