固定化菌藻填料强化人工湿地去除营养盐和PFOS效果研究

Removal effect on nutrient salts and perfluoroalkyl acids by immobilized bacteria and algae packing enhanced constructed wetland

针对全氟辛烷磺酸(Perfluorooctane Sulfonate, PFOS)污染现状,开展3种人工湿地去除复合污染水体中营养盐和全氟辛烷磺酸的效果研究。选取普通垂直流人工湿地(Constructed Wetlands, CW)、固定化菌人工湿地(Immobilized Bacteria Constructed Wetlands, IB-CW)和固定化菌藻填料人工湿地(Immobilized Bacteria Algal Constructed Wetlands, IBA-CW)为研究对象,通过露天试验研究3种湿地在不同质量浓度PFOS下对水体中污染物的去除效果。结果显示,3种湿地对水体中的营养盐和PFOS均具有较好的去除能力,且PFOS对各营养盐的去除具有一定的影响。高质量浓度(100μg/L)PFOS抑制风车草生长,CW植物PFOS质量比达到试验最高值,为(100.56±3.28)μg/g, IB-CW和IBA-CW风车草的总生物量分别比CW增加了10.73%和18.52%。低质量浓度(1μg/L)PFOS促进风车草的生长,IBA-CW风车草总生物量达到了试验最高值,与未加PFOS的处理组相比,生物量增长了16.05%。在高质量浓度PFOS胁迫下,3种人工湿地化学需氧量(Cemical Oxygen Demand, COD)、NH3-N、总氮(Total Nitrogen, TN)和总磷(Total Phosphorus, TP)的去除效果均有所降低。其中,与对照组(无PFOS)相比,IBA-CW对COD、NH3-N、TN、TP的去除率分别降低了(4.23±0.21)百分点、(10.50±0.45)百分点、(13.33±0.51)百分点和(6.87±0.25)百分点,比其他两种湿地降幅小。3种人工湿地均可以有效去除废水中的PFOS,IBA-CW对PFOS的去除率优于CW和IB-CW。3种人工湿地中填料吸附占比均大于植物占比,IBA-CW中填料贡献率比CW高12.90百分点,比IB-CW高5.51百分点。

The removal effect on nutrient salts and PFOS in compound polluted water by three constructed wetlands was studied in view of the current situation of PFOS pollution.Ordinary vertical flow constructed wetlands,immobilized bacteria⁃constructed wetlands,and immobilized bacteria algal packing constructed wetlands were selected as the research objects,and the removal effect on water pollutants by three wetlands under different mass concentrations of PFOS was studied through open⁃air experiments.The results show that the three wetlands have good removal capacity for nutrients and PFOS in water,and PFOS has a certain impact on the removal of nutrients.High mass concentration(100μg/L)of PFOS inhibits the growth of the windmill grass.The PFOS mass ratio of CW plants reaches the highest value in the experiment,up to(100.56±3.28)μg/g.The total biomasses of IB CW and IBA CW are 10.73%and 18.52%higher than that of CW,respectively.Low mass concentration(1μg/L)PFOS promotes the growth of the windmill grass.The total biomass of IBA CW windmill grass reaches the highest value in the experiment,and the biomass increases by 16.05%,compared with the treatment group without PFOS.Under high mass concentration PFOS stress,the removal efficiency of COD,NH3 N,TN and TP of the three constructed wetlands decreases.The removal efficiency of COD,NH3 N,TN,and TP of IBA CW constructs wetlands decreased by(4.23±0.21)percentage points,(10.50±0.45)percentage points,(13.33±0.51)percentage points,and(6.87±0.25)percentage points,respectively,compared with the other two wetlands.The three constructed wetlands can effectively remove PFOS from wastewater,and the removal rate of PFOS by IBA CW constructed wetlands is better than that by CW and IB CW constructed wetlands.The proportion of filler adsorption in the three constructed wetlands was greater than that of plants.The contribution rate of filler in IBA CW constructed wetlands was 12.90 percentage points higher than that in CW⁃constructed wetlands,and 5.51 percentage points higher than that in IB CW constructed wetlands.