Fe<sup>2+</sup>-PDS调理-水平电场脱水工艺对疏浚底泥脱水性能的影响

朱书源; 王毅力

doi:10.12153/j.issn.1674-991X.20230045

Fe²⁺-PDS调理-水平电场脱水工艺对疏浚底泥脱水性能的影响

doi: 10.12153/j.issn.1674-991X.20230045

朱书源,
王毅力^,

北京林业大学环境科学与工程学院, 水体污染源控制技术北京市重点实验室

基金项目: 国家自然科学基金面上项目（51978054）

详细信息

作者简介:
朱书源（1998—），男，硕士研究生，主要从事污泥减量化研究，1352883860@qq.com

通讯作者:
王毅力（1972—），男，教授，研究方向为固体废物处理处置，wangyilimail@126.com

中图分类号: X703
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出版历程
- 收稿日期: 2023-01-16
- 网络出版日期: 2023-11-24

Effect of Fe²⁺-PDS conditioning-horizontal electro-dewatering process on dewatering performance of dredged sediment

ZHU Shuyuan,
WANG Yili^,

Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University

摘要

摘要:
针对高含水率疏浚底泥限制其后续处置的问题，应用Fe²⁺-过二硫酸盐（PDS）调理-水平电场脱水（HED）工艺处理底泥样品，研究响应曲面法对Fe²⁺-PDS调理-HED工艺操作参数（Fe²⁺及PDS的投加量、电压、通电时间）的优化，分析调理过程底泥形貌及性质的变化以及工艺各阶段（调理、重力沉降、电脱水）底泥水分及有机组分的沿程变化。结果表明：1）Fe²⁺和PDS调理底泥时，最佳投加量分别为4和10 mg/g（以TSS计），HED阶段最佳通电时间为80 min，最佳电压为45 V，在上述参数下，脱水底泥含水率由原泥的88.55%降至55.15%。2）在调理阶段，底泥结合水含量由0.44 g/g（以干固体计，全文同）降至0.28 g/g，胞外聚合物（EPS）中蛋白质和多糖总量增加，黏液层（Slime）中蛋白质类物质和可溶性微生物副产物荧光强度降低，紧密附着层（TB-EPS）中总荧光强度增至12.40×10⁷ AU·nm²；在HED阶段，电场作用导致底泥有机物的进一步释放从阴极流出，阴极区EPS各层中的可溶性微生物副产物荧光强度显著增加。3）调理过程产生的硫酸根自由基（SO₄ ⁻·）能够氧化破解底泥中的微生物细胞并将内含物释放至EPS中，同时改变底泥的水分分布与EPS组分特征，原位产生的Fe（Ⅲ）通过絮凝作用改变了底泥的絮体结构，从而有利于底泥脱水性能的提升。
- 疏浚底泥 /
- Fe²⁺-PDS调理 /
- 水平电场脱水 /
- 脱水性能 /
- 胞外聚合物(EPS)
Abstract:
Aiming at the problem of restricting the subsequent disposal of dredged sediment with high water content, Fe²⁺-perdisulfate (PDS) conditioning - horizontal electro-dewatering (HED) process was used to treat sediment samples. The operating parameters (Fe²⁺ and PDS dosage, voltage, power-on time) of Fe²⁺-PDS conditioning - HED process were optimized through the response surface method (RSM), and the variations in the morphology and properties of the sediment at the conditioning stage, as well as the changes in the water content and organic components of the sediment at various stages of the process (conditioning, gravity settling, HED) were analyzed. The results showed as follows: 1) The optimal dosage of Fe²⁺ and PDS for the conditioning stage was 4 mg/g (TSS) and 10 mg/g (TSS), respectively. The optimal power-on time and voltage of the HED stage were 80 min and 45 V, respectively. Under the above parameters, the water content of dredged sediment decreased from 88.55% to 55.15%. 2) At the conditioning stage, the bound water content of sediment decreased from 0.44 g/g (DS) to 0.28 g/g, the total amounts of proteins and polysaccharides in extracellular polymeric substances (EPS) increased, while the fluorescence intensity of protein-like substances and soluble microbial byproduct-like materials (SMBP) in Slime layer decreased. The total fluorescence intensity in the tightly bound EPS (TB-EPS) increased to 12.40×10⁷ AU·nm². At the HED stage, the effect of electric field led to further release of the organic matters in the sediment around the cathode region, and the fluorescence intensity of SMBP in each layer of EPS around the cathode region increased significantly. 3) SO₄ ⁻· produced at the conditioning stage could oxidize and crack the microbial cells in the sediment and release the intracellular contents into EPS, and the simultaneous changes in water distribution and EPS components of the sediment occurred. Fe(Ⅲ) produced in situ altered the floc structure of the sediment through coagulation, thus contributing to the improvement of the dewatering performance of the sediment. The research showed that Fe²⁺-PDS conditioning-HED process could effectively reduce the water content of the dredged sediment, so as to provide technical support for the treatment of dredged sediment.
- dredged sediment /
- Fe²⁺-PDS conditioning /
- horizontal electro-dewatering /
- dewatering performance /
- extracellular polymeric substances (EPS)

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图 1 重力沉降与HED试验装置

Figure 1. Experimental device of gravity settling and horizontal electro-dewatering

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图 2 CST测定装置示意

Figure 2. Schematic diagram of CST testing device

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图 3 Fe²⁺和PDS投加量对底泥SCST及SRF的影响

Figure 3. Effect of Fe²⁺ and PDS dosage on SCST and SRF of the sediment

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图 4 电场条件对底泥含水率和脱水能耗的影响

Figure 4. Influence of the electric field conditions on the sediment water content and dewatering energy consumption

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图 5 调理前后底泥SEM图

Figure 5. SEM images of the sediment before and after conditioning

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图 6 Fe²⁺-PDS调理-HED工艺各阶段底泥的DSC热谱图

Figure 6. DSC thermograms of sediment at different stages of Fe²⁺-PDS conditioning-HED process

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图 7 Fe²⁺-PDS调理-HED工艺各阶段底SCOD的变化

工艺阶段：1—原始底泥；2—调理阶段；3—重力沉降阶段；4—HED阶段（阴极区）；5—HED阶段（阳极区）。

Figure 7. Variations of SCOD at different stages of Fe²⁺-PDS conditioning - HED process

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图 8 Fe²⁺-PDS调理-HED工艺各阶段TOC浓度的变化

注：同图7。

Figure 8. Variations of TOC at different stages of Fe²⁺-PDS conditioning - HED process

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图 9 Fe²⁺-PDS调理-HED工艺各阶段EPS各层中蛋白质、多糖、腐殖酸浓度变化

注：同图7。

Figure 9. Variations of proteins, polysaccharides and humic acids contents of EPS layers (Slime, LB-EPS, TB-EPS) at different stages of Fe²⁺-PDS conditioning-HED process

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图 10 不同阶段底泥EPS各层的三维荧光光谱图

Figure 10. EEM fluorescence spectra of each layer in sediment EPS at different stages of Fe²⁺-PDS conditioning - HED process

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图 11 Fe²⁺-PDS调理-HED工艺各阶段底泥EPS各层的荧光强度及FRI分布

注：横轴中S为Slime；L为LB-EPS；T为TB-EPS。数字代表工艺阶段：1—原始底泥；2—调理阶段；3—重力沉降阶段；4—HED阶段（阴极区）；5—HED阶段（阳极区）。

Figure 11. Fluorescence intensities and FRI distributions of each layer in sediment EPS at different stages of Fe²⁺-PDS conditioning-HED process

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表 1 试验用底泥的理化性质

Table 1. Physicochemical properties of experimental sediment

底泥批次	含水率/%	TSS/(g/L)	VSS/(g/L)	pH	毛细吸水时间/s	电导率/（mS/cm）
第一批	87.73±0.006	131.00±0.13	12.50±0.08	6.82±0.01	61.60±1.06	0.52±0.01
第二批	88.55±0.004	116.40±0.24	10.10±0.23	6.97±0.01	125.00±2.24	0.54±0.01
第三批	90.70±0.013	95.00±0.04	8.40±0.17	6.68±0.01	137.50±2.05	0.55±0.01

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表 2 Fe²⁺和PDS投加量的试验设计

Table 2. Experimental design of Fe²⁺ and PDS dosage

试验编号	Fe²⁺投加量/（mg/g）	PDS投加量/（mg/g）
1	0	0
2	0	20
3	0	50
4	8	0
5	8	20
6	8	50
7	20	0
8	20	20
9	20	50

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表 3 通电时间和电压的试验设计

Table 3. Experimental design of power-on time and voltage

试验组	电压/V	通电时间/min
通电时间的变化	40	10
		20
		30
		60
		120
电压的变化	10	60
	20
	30
	40
	50

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表 4 响应曲面法试验因素水平及编码

Table 4. Code and level of factors chosen for the trials through the response surface method (RSM)

水平	Fe²⁺投加量(X₁)/（mg/g）	PDS投加量(X₂)/（mg/g）	电压(X₃)/V	通电时间(X₄)/min
−1.41	2.34	5.86	8.79	17.57
−1.00	4.00	10.00	10.00	30.00
0.00	8.00	20.00	30.00	60.00
1.00	12.00	30.00	45.00	90.00
1.41	13.66	34.14	51.21	102.43

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表 5 FRI分析法中5个荧光分区

Table 5. Five Ex/Em regions for FRI analysis

区域	（Ex/Em）/（nm/nm）	荧光物质
Ⅰ	200~250/300~330	酪氨酸
Ⅱ	200~250/330~380	色氨酸
Ⅲ	200~250/380~500	富里酸类物质
Ⅳ	250~400/300~380	可溶性微生物副产物
Ⅴ	250~400/380~500	腐殖酸类物质

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表 6 中心复合设计及响应值

Table 6. Central composite design and response values

序号	X₁ / （mg/g）	X₂ / （mg/g）	X₃ /V	X₄ / min	Y₁/%		Y₂/（kW·h/kg）
序号	X₁ / （mg/g）	X₂ / （mg/g）	X₃ /V	X₄ / min	实际值	预期值	实际值	预期值
1	8	20	30	102	58.53	58.97	0.30	0.35
2	4	30	15	90	61.43	61.64	0.12	0.12
3	4	30	15	30	64.71	62.51	0.10	0.07
4	8	34.14	30	60	60.30	60.28	0.40	0.39
5	4	30	45	30	56.54	57.37	0.32	0.33
6	8	20	30	60	58.73	58.91	0.21	0.28
7	8	20	30	60	61.58	58.91	0.28	0.28
8	8	20	51.2	60	57.51	56.89	0.56	0.55
9	4	10	45	90	56.23	54.99	0.31	0.28
10	12	30	15	90	63.43	63.49	0.14	0.16
11	8	20	30	60	59.01	58.91	0.23	0.28
12	8	20	8.8	60	63.47	64.18	0.03	0.01
13	12	10	15	30	65.16	63.95	0.05	0.07
14	12	30	15	30	63.47	64.94	0.06	0.06
15	4	10	15	90	61.76	61.32	0.05	0.02
16	8	20	30	60	57.91	58.91	0.26	0.28
17	12	10	45	30	60.28	60.30	0.40	0.35
18	12	30	45	90	59.44	57.97	1.04	0.91
19	8	5.86	30	60	59.49	59.60	0.23	0.16
20	4	30	45	90	54.01	54.96	0.59	0.61
21	13.66	20	30	60	58.34	58.07	0.28	0.36
22	8	20	30	60	57.85	58.91	0.23	0.28
23	4	10	15	30	62.03	63.73	0.05	0.14
24	12	10	45	90	53.85	55.79	0.46	0.52
25	12	30	45	30	60.77	60.95	0.51	0.58
26	8	20	30	60	58.51	58.91	0.31	0.28
27	12	10	15	90	61.56	60.96	0.06	0.01
28	8	20	30	18	63.09	62.74	0.32	0.20
29	2.34	20	30	60	55.43	55.79	0.19	0.19
30	4	10	45	30	59.26	58.94	0.15	0.16

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表 7 回归方程的方差分析

Table 7. Variance analysis of regression equation

模型	相关系数（R²）	校正后相关系数（R_adj²）	均值	F	P	失拟项	显著性
Y₁	0.874 3	0.757 0	15.900 0	7.45	0.000 2	0.448 2	显著
Y₂	0.937 9	0.905 3	0.122 7	28.71	<0.000 1	0.085 2	显著

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表 8 工艺各阶段底泥水分含量及分布

Table 8. Water content and distribution in sediment at different stages of Fe²⁺-PDS conditioning-HED process g/g　

工艺阶段	总水分	自由水	结合水
原始底泥	9.76±0.13	9.32±0.11	0.44±0.03
Fe²⁺-PDS调理阶段	9.76±0.08	9.48±0.04	0.28±0.01
重力沉降阶段	1.94±0.03	1.66±0.02	0.29±0.01
HED阶段（阴极区）	1.54±0.03	1.23±0.04	0.32±0.01
HED阶段（阳极区）	1.26±0.02	0.97±0.01	0.30±0.01

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