底泥再悬浮对上覆水水质的影响研究  

Influence of Sediment Re-suspension on Black-and-malodorous Status and Water Quality of Overlying Water

作　　者：段余杰[1] 刘小宁[2] 陈光耀[2] 张奇琦 周奎宇 陶益[2] 张锡辉[2] DUAN Yujie;LIU Xiaoning;CHEN Guangyao;ZHANG Qiqi;ZHOU Kuiyu;TAO Yi;ZHANG Xihui(Shenzhen River Regulation Office of Shenzhen, Shenzhen 518052, China;Tsinghua-Kangda Research Institute of Environmental Nano-Engineering & Technology, Graduate School at Shenzhen, Tsinghua University,Shenzhen 518055, China)

机构地区：[1]深圳市治理深圳河办公室,广东深圳518052 [2]清华大学深圳研究生院//清华-康达环境纳米工程技术研究院,广东深圳518055

出　　处：《生态环境学报》2017年第5期837-842,共6页Ecology and Environmental Sciences

基　　金：深圳市水务局水务发展专项资金项目(SZCG2915051767);清华大学深圳研究生院交叉科研创新基金项目(JC2015001);广东省自然科学基金博士科研启动项目(2016A030310024)

摘　　要：城市水体黑臭问题正受到越来越多的关注,而水体中的悬浮物是水体污染物中的重要组成部分。以典型黑臭河流底泥和上覆水构建试验系统,研究底泥再悬浮对上覆水水质的影响。底泥再悬浮后,上覆水中颗粒物粒径立即显著升高,上覆水透明度急剧降低至10 cm以下,氨氮质量浓度升高至15~22 mg·L^(-1),氧化还原电位低于-12 m V,溶解氧低于1.1 mg·L^(-1),底层水体溶解氧甚至低于0.2 mg·L^(-1)。这表明底泥再悬浮是水体黑臭的重要原因之一。在沉降前期,上覆水中颗粒物粒径(D50)随沉降时间延长而显著降低,而在沉降中后期,水柱中各取样点颗粒物粒径稳定在3~4μm(D50)的小粒径水平,维持时间可达20-100 h。随着再悬浮次数增加,水柱恢复澄清的时间延长。底泥再悬浮使水中大粒径颗粒物加速沉降,水体浑浊程度的改善时间缩短,但对致黑的小粒径颗粒物影响较小,与此同时水体褪黑所需时间延长。随着底泥再悬浮-沉降次数的增加,水中硝酸盐氮、磷酸盐、CODCr的质量浓度均显著升高。其中,硝酸盐氮由0.4 mg·L^(-1)升高至0.7 mg·L^(-1),磷酸盐由0.2 mg·L^(-1)升高至1.2 mg·L^(-1),COD_(Cr)由370 mg·L^(-1)升高至524 mg·L^(-1),增幅分别为75%、500%、42%。底泥再悬浮会进一步加剧底泥中污染物向上覆水的释放。Malodorous problems are receiving more and more attention due to severe contamination of urban water bodies.Theparticle matter is an important component for the pollutants in the water body.The influences of sediment re-suspension on waterquality of overlying water were investigated with an experimental system composed of the sediment samples and the overlying waterfrom a typical black-and-malodorous urban river in Shenzhen.The re-suspension of sediments resulted in an increase in the particlessize in overlying water.The transparency of the overlying water became lower than10cm,with the ammonia mass concentrationraised to15~22mg·L-1.The ORP value was lower than-12mV,and the DO values were below1.1mg L-1and0.2mg·L-1for theoverlying water and the bottom water,respectively.These data indicate that sediment re-suspension could be one of the primaryreasons for the deterioration of malodorous water.During the early stage of sedimentation,the particles size in overlying water(D50)decreased with time,while the particles size remained at a constant level of3~4μm for20-100h during the later stage.Sedimentre-suspension accelerated the sedimentation for the particles with large sizes,and shortened the time required for the recovery ofwater clarity.However,the particles with small sizes that may contribute to the black status were less affected by sedimentre-suspension.Therefore,the time for the disappearance of black color was extended due to repeated sediment re-suspension.Withthe increase in the number of times for sediment re-suspension,the mass concentrations of CODCr,nitrate and phosphate had asignificant increase,rising from370mg·L-1,0.4mg·L-1and0.2mg·L-1to524mg·L-1,0.7mg·L-1and1.2mg·L-1,respetively.Theconclusion can be made that sediment re-suspension will aggravate the release of pollutants from the sediment to overlying water.

关 键 词：黑臭水体 底泥再悬浮 上覆水 颗粒物粒径 氮磷 

分 类 号：X522[环境科学与工程—环境工程]