Modification of aged oily sludge (AOS) through pressure filtration and electro-dewatering methods under citric acid (CA) pretreatment

IF 12.4 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL Water Research Pub Date : 2025-04-07 DOI:10.1016/j.watres.2025.123597

Junjie Hu, Miaomiao Zhao, Chen Li, Zhiyang Gong, Zeying Sun, Degang Ma

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Abstract

Aged oily sludge (AOS) exhibits more challenging properties compared to ordinary oily sludge, making modification treatments essential for improving dewatering efficiency. This study innovatively employs citric acid (CA) as a pretreatment agent for AOS and combines pressure filtration (PF) and electro-dewatering (EDW) to conduct volume reduction experiments, while investigating the dewatering mechanism of CA pretreatment. Under a pressure of 75 kPa, the AOS moisture content decreased slightly from 80.12 % to 78.00 %, while the addition of 0.02 g CA/g AOS further reduced it to 71.69 %. Under conditions of 25 kPa and 25 V/cm, EDW lowered the moisture content to 47.36 %, achieving faster average dewatering rate of 0.086 g/s. This study investigated the oil and water distribution within sludge cake layers, analyzed their migration during EDW, and explained the anodic drying phenomenon. Engineering applicability was assessed through energy consumption and calorific value analyses. Mechanistic insights revealed oil component changes, highlighting the roles of surfactants, electric field forces, pH, and temperature. Formula-based calculations were also conducted for field-driven processes. This study presents an innovative deep dewatering technology for AOS, investigating the dewatering mechanism from various perspectives, including demulsification, electric field, pH, and thermal effects. Additionally, it evaluates the energy consumption and economic cost, providing a theoretical foundation for its engineering applicability and offering new perspectives for the treatment and disposal of AOS.

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柠檬酸预处理下压力过滤和电脱水法改性老化含油污泥

与普通含油污泥相比，老化含油污泥表现出更具挑战性的特性，因此对其进行改性处理对于提高脱水效率至关重要。本研究创新性地采用柠檬酸（CA）作为AOS的预处理剂，结合压力过滤（PF）和电脱水（EDW）进行减容实验，同时探讨CA预处理的脱水机理。在75 kPa压力下，AOS含水率由80.12%略微下降至78.00%，添加0.02g CA/g AOS进一步降低至71.69%。在25 kPa、25 V/cm条件下，EDW将含水率降低至47.36%，平均脱水速率达到0.086 g/s。研究了油水在污泥饼层内的分布，分析了油水在EDW过程中的迁移，并对阳极干燥现象进行了解释。通过能耗和热值分析评价了工程适用性。机理分析揭示了油组分的变化，强调了表面活性剂、电场力、pH和温度的作用。对现场驱动过程也进行了基于公式的计算。本研究提出了一种创新的AOS深度脱水技术，从破乳、电场、pH和热效应等多个角度探讨了AOS的脱水机理。并对其能耗和经济成本进行了评价，为其工程适用性提供了理论基础，为AOS的处理处置提供了新的视角。

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来源期刊

Water Research 环境科学-工程：环境

CiteScore

20.80

自引率

9.40%

发文量

1307

审稿时长

38 days

期刊介绍： Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include: •Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management; •Urban hydrology including sewer systems, stormwater management, and green infrastructure; •Drinking water treatment and distribution; •Potable and non-potable water reuse; •Sanitation, public health, and risk assessment; •Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions; •Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment; •Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution; •Environmental restoration, linked to surface water, groundwater and groundwater remediation; •Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts; •Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle; •Socio-economic, policy, and regulations studies.