摘要
有效疏浚深度是决定疏浚工程造价和治理效果的关键指标,目前我国现行标准规范尚未明确底泥营养盐浓度的标准,对营养盐超标河湖污染底泥的评价和有效疏浚深度确定十分不利。以太原汾河示范段为例,取其代表性柱状样0.3~0.4、0.9~1.0、1.4~1.6、1.9~2.0 m深度的底泥,分别设计Ⅰ类~劣Ⅴ类氨氮(NH4^+-N)、正磷酸盐(PO4^3-)的模拟水和柱状样实际上覆水,进行氮、磷吸附/解吸试验,并分析不同深度底泥氮、磷吸附/解吸特征。结果表明:柱状样1.6 m深度以内底泥中NH4^+-N对水体呈释放状态,1.9 m深度底泥对水体中NH4^+-N具一定吸附性;1.6 m深度以内底泥中PO4^3-对水体有释放风险,1.9 m深度底泥对水体中PO4^3-具一定吸附性;1.3 m深度底泥中总氮(TN)、NH4^+-N浓度出现较明显的拐点,1.6 m深度底泥中总磷(TP)浓度出现较明显的拐点。结合底泥对上覆水体影响及底泥中氮、磷浓度垂向变化等因素,确定太原汾河示范段有效疏浚深度为1.6 m。
Effective dredging depth is the key index to determine dredging cost and treatment effect.There is no standard stipulation for nutrient content in sediment in the current standards and specifications in China,which is very unfavorable to the evaluation and determination of effective dredging depth of polluted sediment in rivers and lakes with excessive nutrient salt.Taking the demonstration section of dredging of Fenhe River in Taiyuan as an example,the sediments with the depth of 0.3-0.4,0.9-1.0,1.4-1.6 and 1.9-2.0 m were taken as representative core samples.The simulated water of NH4^+-N and PO4^3-with GradeⅠto worse than GradeⅤand the overlying water of core samples were designed respectively to carried out nitrogen and phosphorus adsorption/desorption experiments,and the nitrogen and phosphorus adsorption/desorption characteristics of sediment at different depths were also analyzed.The results showed that NH+4-N in the sediment within 1.6 m of the core sample was released to the water body,and the sediment at a depth of 1.9 m had certain adsorption to NH4^+-N in the water body.PO4^3-in the sediment within 1.6 m had a risk of release to water body,and the sediment at a depth of 1.9 m had certain adsorption to PO4^3-in water body.The concentrations of TN and NH4^+-N in the sediment at a depth of 1.3 m showed an obvious inflection point,and the concentration of TP in the sediment at a depth of 1.6 m showed an obvious inflection point.Comprehensively considering the influence of the sediment on overlaying water body and the vertical variation of sediment nitrogen and phosphorus concentrations,the effective dredging depth of Fenhe River demonstration section in Taiyuan was determined to be 1.6 m.
作者
马永刚
程瑾
励彦德
葛高岭
苏召斌
MA Yonggang;CHENG Jin;LI Yande;GE Gaoling;SU Zhaobin(CCCC (Tianjin) Eco-Environmental Protection Design & Research Institute Co., Ltd.;Tianjin Key Laboratory for Dredging Engineering Technology Enterprises)
出处
《环境工程技术学报》
CAS
2020年第3期392-399,共8页
Journal of Environmental Engineering Technology
关键词
污染底泥
氮
磷
吸附/解吸
平衡浓度
有效疏浚深度
polluted sediment
nitrogen
phosphorus
adsorption/desorption
equilibrium concentration
effective dredging depth
