摘要
以土工管袋法脱水固结底泥为对象,对巢湖清淤底泥固结前后管袋内底泥氮磷形态以及释放特征进行分析,研究土工管袋固结法对疏浚底泥氮磷转化影响及释放风险。结果表明,与湖体原泥相比,固结后底泥有机质和总氮均出现下降趋势(有机质下降10.87%,总氮含量下降3.50%),但总磷明显升高(增幅约18.89%)。同时,固结后底泥最大吸附量(Qm)较未固结底泥增幅约1.35倍,为0.89 mg·g^(-1)。固结后底泥等温平衡浓度(EPC0)较固结前底泥降低约1.58倍,这表明疏浚底泥固结后磷释放风险降低。氮磷形态分析结果表明,管袋固结后氨氮含量降低,但硝氮的质量浓度没有明显变化。固结后底泥中铁结合态磷、铝结合态磷较未固结底泥分别增加约1.20、1.49倍,有机磷含量则较固结前底泥下降约71.6%。静态释放结果表明,固结底泥氮释放随温度增加而增加,其中30℃条件下固结底泥氨氮释放速率为3.31mg·(m^(2)·d)^(-1),约是湖体未固结底泥10%。但固结底泥磷处于吸收状态,其中30℃条件下磷酸根吸收速率最大为2.74 mg·(m^(2)·d)^(-1)。以上结果表明,固结底泥氮磷总量、活性态及其释放通量均降低,再次释放风险较小。
In this study,the geotechnical pipe bag method of dewatering consolidated sediment was used as the object to analyse the nitrogen and phosphorus morphology and release characteristics of the sediment in the pipe bag before and after the consolidation of dredged sediment in Chaohu Lake.The impact of geopipe bag consolidation on nitrogen and phosphorus transformation of dredged sediments and the risk of release was studied.The results showed that,compared with the original sediment of the lake,the organic matter and total nitrogen content of the solidified sediment decreased(organic matter decreased by 10.87%,total nitrogen content decreased by 3.50%),but the total phosphorus increased significantly(increased by about 18.89%).Meanwhile the maximum adsorption capacity(Qm)of solidified sediment increased about 1.35 times compared with uncured sediment,which was 0.89 mg·g^(-1).The isothermal equilibrium concentration(EPC0)of the cured substrate was about 1.58 times lower than that of the substrate before curing,indicating that the risk of phosphorus release was reduced after the substrate was cured.Nitrogen and phosphorus patterns showed that ammonia nitrogen content decreased after curing of the pipe bags,but nitrate nitrogen content did not change significantly.Fe-P and Al-P in the cured substrate increased by about 1.20 and 1.49 times,respectively,compared with the unsolidified substrate,while the Org-P content decreased by about 71.60%compared with that of the pre-solidified sediment.The results of static release showed that the nitrogen release from the cured sediments increased with the increase of temperature,in which the ammonia nitrogen release rate from the cured sediments at 30℃ was 3.31 mg·(m^(2)·d)^(-1),which was about 10%of the uncured sediments in the lake body.However,cured substrate phosphorus was in the uptake state,with the maximum phosphate uptake rate of 2.74 mg·(m^(2)·d)^(-1) at 30℃.The above results showed that the total amount of nitrogen and phosphorus in the cured substrate,the active state and its release fluxes was all reduced,with low risk of re-release.
作者
李发建
关宇
李延勋
曾勋才
赵琼
尹洪斌
LI Fajian;GUAN Yu;LI Yanxun;ZENG Xuncai;ZHAO Qiong;YIN Hongbin(School of Resource and Environmental Engineering,AnHui University,Hefei 230601,China;China Electric Construction Municipal Construction Group Limited,Tianjin 300384;Anhui Yushun Water Conservancy Engineering Management Company Limited,Fuyang 230092;Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,China)
出处
《环境工程学报》
CAS
CSCD
北大核心
2023年第12期3943-3952,共10页
Chinese Journal of Environmental Engineering
基金
中国科学院基础前沿科学研究计划项目(ZDBS-LY-DQC018)。
关键词
巢湖
土工管袋
固结底泥
释放
氮磷形态
Chaohu Lake
geotube bags
solidified sediment
release
nitrogen and phosphorus forms
