Making waves: Reevaluating iron dosing for carbon recovery in mainstream wastewater treatment system

IF 11.4 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Water Research Pub Date : 2025-05-20 DOI:10.1016/j.watres.2025.123875

Nan Shen , Liyan Wei , Xiao Wang , Fei Yang , Jie Ma , Yun Chen , Yan Zhou

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引用次数: 0

Abstract

Wastewater treatment plants face significant challenges in shifting from energy-intensive operations to carbon-neutral, energy-efficient systems. One promising strategy is the iron-enhanced primary treatment process (Fe-CEPT), which focuses on capturing organic carbon for energy recovery rather than biological oxidation. However, while Fe-CEPT has been implemented in wastewater treatment, its potential effects on downstream processes have often been overlooked. This viewpoint takes a comprehensive look at iron dosing for carbon recovery in mainstream wastewater treatment systems. Fe-CEPT has proven effective at capturing particulate organics and phosphorus. However, it is less successful in removing soluble organic carbon. Additionally, the high iron content in sludge, typically between 100 to 200 mg Fe/g SS, has been shown to severely inhibit methane production. This finding contrasts with earlier studies that suggested iron could enhance methane production. It was found the elevated iron levels bind around 20 % of the carbon in the sludge, limiting its bioavailability. These findings indicate that coupling Fe-CEPT with anaerobic digestion may not be an effective method for carbon recovery. A more promising approach that involves limiting iron dosing to less than 10 mg Fe/L in a high-rate activated sludge (HRAS) system is proposed. This strategy combines the benefits of iron dosing and HRAS system, offering a potential pathway to enhance carbon recovery, improve phosphorus management, and reduce the environmental impact of wastewater treatment processes.

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掀起波澜：对主流污水处理系统中碳回收的铁投加再评价

污水处理厂在从能源密集型操作转向碳中和、节能系统方面面临重大挑战。一种有前景的策略是铁增强初级处理工艺（Fe-CEPT），其重点是捕获有机碳进行能量回收，而不是生物氧化。然而，尽管Fe-CEPT在废水处理中得到了应用，但其对下游工艺的潜在影响往往被忽视。这一观点全面审视了主流废水处理系统中碳回收的铁剂量。Fe-CEPT已被证明在捕获颗粒有机物和磷方面是有效的。然而，它在去除可溶性有机碳方面不太成功。此外，污泥中的高铁含量（通常在100至200 mg Fe/g SS之间）已被证明严重抑制了甲烷的产生。这一发现与早期的研究结果形成了对比，之前的研究认为铁可以促进甲烷的产生。研究发现，升高的铁含量与污泥中约20%的碳结合，限制了污泥的生物利用度。这些发现表明，Fe-CEPT与厌氧消化耦合可能不是有效的碳回收方法。提出了一种更有前途的方法，将高速率活性污泥（HRAS）系统中的铁剂量限制在10 mg Fe/L以下。该策略结合了铁投加和HRAS系统的优点，为提高碳回收率、改善磷管理和减少废水处理过程对环境的影响提供了一条潜在途径。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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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.