摘要
水产养殖清塘过程中的排水是造成周边水环境污染的重要环节,但对此环节中污染物排放特征和影响程度的研究仍相对不足。为有效减少清塘过程的排水对环境的污染,推进水产养殖业绿色发展,本研究选取典型鱼类集约化养殖区,通过高频采样和监测,分析了阶段式排水时混养鱼塘尾水中的悬浮物、有机物和营养盐等指标的浓度变化,明确污染物的排放特征,同时分析受纳水体不同断面的水质变化情况。研究结果表明:总悬浮物浓度(TSS)、高锰酸盐指数(COD_(Mn))、总磷(TP)、总氮(TN)和氨氮(NH_(3)-N)浓度随着持续排水呈上升趋势,在排水末期污染物浓度均快速上升,磷酸盐磷(PO_(4)^(3-)-P)浓度仅在排水末期骤升,硝态氮(NO_(3)^(-)-N)浓度随排水持续下降,亚硝态氮(NO_(2)^(-)-N)浓度随排水先上升后下降;根据《淡水池塘养殖水排放要求》二级标准,排水末期TN、TP、TSS浓度超标倍数分别达4.70、6.66、206.90;尾水流量与河流量约以1/200的比例排入河道后,仅TSS、COD_(Mn)、TN和NH_(3)-N对距排水口400 m内的河道水质产生显著性影响,影响距离为TN>TSS=NH_(3)-N>COD_(Mn)。因此,禁止水产养殖尾水未经处理直接排放,特别是池塘最后20~30 cm水深的尾水未经处理直接排入附近河道,可有效限制水产养殖尾水污染物负荷集中输出。
The drainage process during aquaculture pond cleaning would cause non negligible pollution of surrounding water environment,but there haven t been sufficient research on the characteristics of pollutant discharges and the impact degrees of this process.To effectively mitigate the environmental pollution from the drainage of pond cleaning process and promote the green development of aquaculture industry,in this study,we selected a typical intensive fish aquaculture area as the study object.Through high frequency sampling,we analyzed the changes of suspended matters,organic matters and nutrients concentrations in the tailwater of mixed fishponds to understand the discharge characteristics of pollutants.The changes of water quality in different sections of the receiving water were analyzed as well.According to our results,the concentrations of total suspended solids concentration(TSS),COD_(Mn),total phosphorus(TP),total nitrogen(TN)and ammonia nitrogen(NH_(3)-N)all exhibited an increasing trend with the drainage and increased rapidly at the end of the drainage event.The concentration of phosphate(PO_(4)^(3-)-P)increased rapidly only at the end of the drainage event,while the concentration of nitrate nitrogen(NO_(3)^(-)-N)decreased continuously during the whole drainage event.According to the secondary standard of"Freshwater Pond Culture Water Discharge Requirements",the exceedance multiples of TN,TP and TSS at the end of discharge reached 4.70,6.66 and 206.90,respectively.After the tailwater flow discharged into the external river at a ratio of about 1/200 to the river volume,within 400 m from the outlet,only TSS,COD_(Mn),TN and NH_(3)-N would significantly affect the river water quality,and the influencing distance exhibited a trend of TN>TSS=NH_(3)-N>COD_(Mn).Therefore,prohibiting direct discharge of aquaculture tailwater into the nearby river without treatment,especially the tailwater of the last 20-30 cm water depth of the pond,can effectively limit the output loads of the concentrated pollutants in aquaculture
作者
梁利权
郭春霞
陈小华
李金文
陈诚
杨林沛
沈根祥
Liang Liquan;Guo Chunxia;Chen Xiaohua;Li Jinwen;Chen Cheng;Yang Linpei;Shen Genxiang(School of Resources and Environmental Engineering,East China University of Science and Technology,Shanghai 200237,P.R.China;State Environmental Protection Key Laboratory of Environmental Health Impact of Emerging Contaminants,Shanghai Academy of Environmental Sciences,Shanghai 200233,P.R.China)
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2023年第1期181-191,共11页
Journal of Lake Sciences
基金
水体污染控制与治理科技重大专项(2017ZX07207002)
上海市生态环境局沪环科[2021]第4号
上海市农业农村委沪农科推字(2021)第3-1号项目联合资助
关键词
水产养殖
清塘
排水
悬浮固体
富营养化
太湖流域
Aquaculture
pond cleaning
drainage
suspended solid
eutrophication
Taihu Basin
