絮凝控制高浓度藻华对水质和植被恢复的影响  

Effects of controlling heavy cyanobacterial blooms through flocculation on water quality and submerged macrophyte restoration.

作　　者：杨瑾晟 姜磊 芦津 陈开宁[1] 谢三桃 张民[1] 史小丽[1] YANG Jin-sheng;JIANG Lei;LU Jin;CHEN Kai-ning;XIE San-tao;ZHANG Min;SHI Xiao-li(State Key Laboratory of Lake Science and Environment,Nanjing Institute of Geography and limnology,Chinese Academy of Sciences,Nanjing 210008,China;University of Chinese Academy of Sciences,Beijing 100049,China;Anhui Water Resources and Hydropower Survey,design and Research Institute Co.,Ltd,Hefei 230088,China)

机构地区：[1]中国科学院南京地理与湖泊研究所,湖泊与环境国家重点实验室,江苏南京210008 [2]中国科学院大学,北京100049 [3]安徽省水利水电勘测设计研究总院有限公司,安徽合肥230088

出　　处：《中国环境科学》2023年第2期561-567,共7页China Environmental Science

基　　金：中国科学院STS项目(KFJ-STS-QYZD-2021-01-002);国家自然科学基金资助项目(32071573,41877544)。

摘　　要：模拟了叶绿素a浓度为1001.63μg/L的高浓度蓝藻水华,选用聚合氯化铝(PAC),氯化铁(FeCl_(3)),阳离子淀粉-壳聚糖(CSC)3种絮凝剂实施应急控藻,探究其对水质和沉水植被恢复的影响.研究发现,FeCl_(3)和CSC处理后水体DO分别降至1.35,0.61mg/L,氨氮则高达24.93,45.74mg/L,引发水体持续的重度黑臭;相比之下,PAC处理后ORP、DO、氨氮明显改善,分别为-76.00mV、3.64mg/L、9.25mg/L,且优于空白处理的-140.43mV、2.34mg/L、13.10mg/L,水体重度黑臭持续时长从15d减少至4d,沉水植被恢复潜力提升,其中伊乐藻(Elodea canadensis)的生物量显著增加,优于无藻华对照(P<0.05);FeCl_(3)和CSC处理未能缓解苦草(Vallisneria natans),伊乐藻受到的生长胁迫,甚至加剧了对伊乐藻的生长胁迫,且CSC处理显著抑制了伊乐藻的叶数,株高,生物量的增长(P<0.05).结果表明,絮凝沉降可以快速控制湖滨带高浓度蓝藻水华,但可能会产生黑臭,应考虑增加曝气增氧等措施以缓解水质恶化,并选取合适的沉水植被进行生态修复,以期实现长效控藻目标.Cyanobacterial blooms could accumulate and form high concentration algal scum in the leeward lakeside,which could seriously damage the aquatic ecology health.Flocculation-sinking is one of the most effective approaches for rapidly mitigating heavy cyanobacterial blooms.But the potential risk of water deterioration would affect the subsequent lake restoration strategies.In this study,three flocculants including polyaluminum chloride(PAC),ferric chloride(FeCl_(3))and cationic starch with chitosan(CSC),were used to control heavy cyanobacterial blooms with the chlorophyll-a concentration of 1001.63µg/L.Then,the impacts of flocculation on water quality and submerged macrophyte restoration were evaluated.The result showed that the water turned to black and odorous in FeCl_(3)and CSC treatments,with DO dropping to 1.35mg/L and 0.61mg/L,and ammonia nitrogen increasing to 24.93mg/L and 45.74mg/L,respectively.While in PAC treatment,ORP(-76.00mV),DO(3.64mg/L)and ammonia nitrogen(9.25mg/L)were ameliorated,compared with those of-140.43mV,2.34mg/L,and 13.10mg/L in control treatment,respectively.The duration of severe black-and-odorous water decreased from 15d to 4d,and the restoration potential of submerged macrophyte was promoted.Particularly,the biomass of Elodea canadensis increased significantly,compared with that of the control without cyanobacterial blooms(P<0.05).However,the growth stress of Vallisneria natans and Elodea canadensis in FeCl_(3)and CSC treatments was not to be alleviated.CSC treatment could inhibit the growth of leaf,plant height and biomass of Vallisneria natans(P<0.05).Results showed that flocculation and sedimentation could quickly control the heavy cyanobacterial blooms in the lakeside area,but black and odorous water event may occur.Measures,such as aeration for oxygenation,should be implemented to alleviate the deterioration of water quality.Afterwards,appropriate submerged macrophyte should be selected for ecological restoration,for achieving the goal of long-term algal control.

关 键 词：湖滨带 絮凝控藻 高浓度藻华 水体黑臭 沉水植物恢复 

分 类 号：X524[环境科学与工程—环境工程]