Aerobic biological treatment of hydrothermal liquefaction process water of sewage sludge: Nitrification inhibition and removal of hazardous pollutants

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

Water Research Pub Date : 2025-02-22 DOI:10.1016/j.watres.2025.123351

Williane Vieira Macêdo , Jakob Schelde Madsen , Patrick Schacksen , Rellegadla Sandeep , Jeppe Lund Nielsen , Patrick Biller , Leendert Vergeynst

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Abstract

Integrating hydrothermal liquefaction (HTL) in wastewater treatment is promising for converting sewage sludge into biofuels and fertilizers. However, challenges arise due to the ecotoxicity and nitrification-inhibiting properties of HTL process water. This study investigated the activated sludge treatment of HTL process water in continuous lab-scale reactors, focusing on the adaptive capacity of microbial communities and degradation of HTL-derived pollutants. Continuous activated sludge reactors were operated with process water up to expected levels of 145 mgCOD⋅L⁻¹. Results showed that prolonged exposure did not adversely affect the removal of organic matter, organic nitrogen and ammonium nitrogen. Activated sludge treatment with a hydraulic retention time of 15 h was able to reduce the nitrification inhibition potential in the effluent by 63–69 % compared to the influent. Furthermore, nitrification inhibition assays showed a 2.6 times reduced sensitivity in adapted versus non-adapted biomass. The nitrifying community composition was unaltered after several months of exposure, suggesting that heterotrophic degradation of inhibitory compounds protected the nitrifying community from the cytotoxic effects. Chemical analysis identified 40 pollutants in the process water, of which activated sludge effectively degraded amines, linear and cyclic amides, cyclic ketones, and hydroxy aromatics with removal efficiencies above 90 %. However, nitrogen-containing heterocyclic compounds, particularly alkylated pyrazines and methylquinoline, were more recalcitrant to treatment, with removal rates ranging from 10 to 80 %. Effluent concentrations for some of these compounds, ranging from 1 to 50 µg⋅L⁻¹, were close to or surpassed the predicted no-effect concentrations, raising concerns about potential environmental impacts of integrating hydrothermal liquefaction into conventional wastewater treatment plants.

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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.