Article
Environmental Sciences
Tanmoy Das, Shane P. Usher, Damien J. Batstone, Maazuza Othman, Catherine A. Rees, Anthony D. Stickland, Nicky Eshtiaghi
Summary: Systematic and comprehensive characterisation of shear and solid-liquid separation properties of sludge across a wide range of solids concentration and volatile solids destruction (VSD) is critical for design and optimization of the anaerobic digestion process. In addition, there is a need for studies at the psychrophilic temperature range as many unheated anaerobic digestion processes are operated under ambient conditions with minimal self-heating. For shear rheology, the viscosity increased with the increase of VSD, while other parameters had a negligible impact. For solid-liquid separation, no significant impact of VSD on the solids flux, underflow solids concentrations or specific solids throughput was observed in the thickener and filtration model, but there was an increase in average cake solids concentration, indicating better dewatering behaviour.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Review
Engineering, Environmental
Zhiyao Wang, Tao Liu, Haoran Duan, Yarong Song, Xi Lu, Shihu Hu, Zhiguo Yuan, Damien Batstone, Min Zheng
Summary: The study reviewed the current status and challenges of post-treatment technologies for anaerobically digested sludge, proposing a multi-target approach to achieve sludge volume reduction, stabilization, and metal solubilization. The authors suggested developing more methods to promote AD sludge management towards a more economically favorable, socially acceptable, and environmentally sustainable direction.
Article
Green & Sustainable Science & Technology
Chen Cai, Chongliang Hu, Wan Yang, Yu Hua, Lei Li, Donghai Yang, Xiaohu Dai
Summary: The study investigated the effects of post-thermal hydrolysis process (THP) temperature on methane yields, dewatering performance, and antibiotic resistance genes (ARGs) in sludge digestate. Results showed that temperatures above 160 degrees C were optimal, leading to increased methane yield, improved dewatering performance, and reduced abundance of ARGs. The energy balance analysis indicated that the AD-THP configuration could be a promising alternative for sustainable disposal of excess sludge, with a net energy output up to 372 kW.h/t DS.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Engineering, Environmental
Huan Liu, Xuan Li, Zehao Zhang, Long D. Nghiem, Li Gao, Qilin Wang
Summary: This study demonstrated that pretreatment of secondary sludge with free ammonia enhanced volatile solids destruction and methane production in semi-continuous anaerobic digestion systems. The FA pretreatment also improved sludge dewaterability and pathogen removal efficiency, while reducing the volume of dewatered sludge and overall cost. These findings suggest a promising strategy to enhance sludge reduction in anaerobic digestion processes.
Article
Chemistry, Multidisciplinary
Maria Cristina Collivignarelli, Sara Todeschini, Stefano Bellazzi, Marco Carnevale Miino, Francesca Maria Caccamo, Silvia Calatroni, Marco Baldi, Sauro Manenti
Summary: This study investigates the rheological properties of thermophilic biological sludge and evaluates the influence of non-volatile solids. The concentration of sodium bentonite significantly affects the consistency coefficient of the sludge. Thixotropic behavior is more pronounced at higher shear rates and can be represented by a double exponential fitting model.
APPLIED SCIENCES-BASEL
(2022)
Article
Green & Sustainable Science & Technology
Zhi Lin, Zong-Lin Wu, Zhao-Yong Sun, Min Gou, Zi-Yuan Xia, Yue-Qin Tang
Summary: The study found that ADS is not suitable as fertilizer, but composting post-treatment can stabilize ADS and degrade some organic matter, resulting in a mature compost product; typical ARG abundance reduced four-fold during ADS composting, and aerobic composting can effectively stabilize organic matter and reduce ARG abundance.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Engineering, Environmental
Tanmoy Das, Shane P. Usher, Damien J. Batstone, Catherine A. Rees, Anthony D. Stickland, Nicky Eshtiaghi
Summary: Due to the non-homogeneous and multiphase nature of anaerobic lagoon constituents, continuous functions are required to describe shear and solid-liquid separation properties in CFD modelling for process optimization. However, the measurement of existing material properties of anaerobic sludges is limited to certain aspects and concentrations. This study measured the shear properties and solid-liquid separation properties of an anaerobic sludge across a wide range of concentrations, enabling CFD modeling of the hydrodynamics and performance of anaerobic lagoons.
Article
Environmental Sciences
Sahar S. Dalahmeh, Gunnar Thorsen, Hakan Jonsson
Summary: During a 12-month study in Sweden, it was found that open-air storage without composting showed effective removal of hormones and antibiotics, but lower removal of pharmaceutically active substances. Composting resulted in degradation of hormones and a noticeable difference in concentrations of pharmaceuticals between the top and deeper layers of sludge piles.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Chemistry, Multidisciplinary
Sebastian Kujawa, Gniewko Niedbala, Wojciech Czekala, Katarzyna Pentos
Summary: Waste management is a crucial aspect of environmental protection, and the treatment of municipal sewage sludge is a significant challenge. Composting with other substrates, like maize straw, is a reasonable method for sewage sludge treatment. This study proposed a method for determining the total solids and volatile solids content in composted mixtures using image analysis and neural networks. The most accurate models were obtained by considering 30 image color and texture parameters, along with three features describing the composted material. The developed models had uncertainties with MAPE errors of 2.88% and 0.59% for total solids and volatile solids content prediction.
APPLIED SCIENCES-BASEL
(2023)
Article
Green & Sustainable Science & Technology
Wei Wei, Zhijie Chen, Derek Hao, Xiaoqing Liu, Bing-Jie Ni
Summary: This study improved daily methane production and VS destruction in continuous anaerobic digestion by using natural diatomite as a mediator. The microbial community in the digester shifted towards a more favorable direction, and process modeling showed increased hydrolysis rate and biomethane potential. Natural diatomite mitigated ammonia inhibition and enhanced electron transfer for WAS-to-methane conversion.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Engineering, Chemical
Kaiyu Fang, Xu Zeng, Guodong Yao, Siqing Xia, Jianfu Zhao, Yangyuan Zhou, Yuting Zhu, Xuejun Li, Chanjuan Qu
Summary: The study found that total suspended solids and chemical oxygen demand of pharmaceutical sludge were effectively removed during wet oxidation treatment, with an increase in volatile fatty acid concentration, indicating the potential for the sludge solution to be used as a carbon source. Scanning electron microscopy images showed that the structure of the sludge became loose and porous after treatment, which is beneficial for dewatering performance.
Article
Engineering, Chemical
Branda Jian Tong Yap, Gan Chin Heng, Choon Aun Ng, Mohammed J. K. Bashir, Serene Sow Mun Lock
Summary: This study aims to explore new opportunities for treating palm oil mill effluent waste activated sludge (POME WAS) with high organic content and low degradability, and to convert it into energy. The results showed that optimized electrochemical oxidation (EO) of pre-treated WAS before anaerobic digestion (AD) can improve the digestibility of POME WAS, with enhanced solids minimization and biogas production. It achieved a 1.6-fold increase in sludge minimization and a total chemical oxygen demand (COD) removal of 68.8%, along with a 94% increment in methane production.
Article
Environmental Sciences
Jiaxin Gao, Zeyu Li, Hongbo Chen
Summary: This study reveals the key role of total solids (TS) content in the thermal-alkaline pre-treatment (TAP) and anaerobic digestion (AD) of waste activated sludge. Optimal TS content enhances sludge disintegration and methane production, while excessive TS content deteriorates sludge fluidity and hampers the disintegration process. Maintaining an appropriate TS content is crucial for efficient TAP and AD technology.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Agricultural Engineering
Ander Castro-Fernandez, Anton Taboada-Santos, Sabela Balboa, Juan M. Lema
Summary: The study compared the potential to produce volatile fatty acids (VFA) from sewage sludge, both raw and thermally pre-treated. In batch mode, raw sludge obtained the highest maximum VFA yield at pH 8, while pre-treated sludge achieved a lower value. Continuous reactor operation showed that thermal hydrolysis pre-treatment (THP) did not significantly influence VFA yields. Microbial community analysis revealed that the phylum Fumicutes was predominant in both reactors and the enzymatic profiles involved in VFA production were similar regardless of the substrate fed.
BIORESOURCE TECHNOLOGY
(2023)
Article
Engineering, Environmental
Luisa Niero, Fernando Morgan-Sagastume, Anders Lagerkvist
Summary: The study demonstrated the impact of temperature, pH, and retention time on the acidogenic fermentation of sewage sludge with wood fly ash added. Higher temperatures and adjusted pH favored hydrolysis, while fermentation producing organic acids was faster at lower temperatures.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2021)