The preconditioning of digested sludge in sludge filtration systems produces hydrogen sulfide (HS), a major odor-causing source. This study evaluated the effects of adding HS-removing bacteria to sludge-filtration systems. Ferrous-oxidizing bacteria (FOB) and sulfur-oxidizing bacteria (SOB) were mass-cultivated in a hybrid bioreactor equipped with an internal circulation system. In this bioreactor, FOB and SOB effectively removed >99% of HS; however, the acidic conditions created by adding a coagulant during digested sludge preconditioning were more favorable for FOB than for SOB. In batch tests, SOB and FOB removed 94 ± 1.1% and 99 ± 0.1% of HS, respectively; therefore, digested sludge preconditioning proved more suitable for FOB activity than SOB activity. The results revealed that the optimal FOB addition ratio was 0.2%, validated using a pilot filtration system. Moreover, the 57.5 ± 2.9 ppm HS generated in the sludge preconditioning step was reduced to 0.01 ± 0.01 ppm after adding 0.2% FOB. Therefore, the results of this study will be useful because they provide a process for biologically removing odor-causing sources without affecting the dewatering efficiency of the filtration system.
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http://dx.doi.org/10.1016/j.jbiosc.2023.02.005 | DOI Listing |
J Environ Manage
January 2025
Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, School of Environment, South China Normal University, Guangzhou, 510006, China; Institute of Science and Technology Innovation Co., Ltd., South China Normal University, Qingyuan, 511517, China. Electronic address:
Zero-valent iron (ZVI) has been confirmed in enhancing methane production by improving interspecies electron transfer during anaerobic digestion (AD) of waste activated sludge (WAS). In this study, we suppose that sulfidated zero-valent iron (S-ZVI), a semiconductor material, has better property of electron transfer in AD process. Based on two-phase anaerobic digestion process, nitrite and S-ZVI were used separately for improving acidogenic phase and methanogenic phase of anaerobic sludge digestion.
View Article and Find Full Text PDFKorean J Gastroenterol
January 2025
Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Hepatic tuberculosis, typically associated with miliary tuberculosis, can occasionally present as localized liver lesions. This case report describes a 77-year-old male presenting with persistent abdominal pain and fever, following an endoscopic retrograde cholangiopancreatography for bile duct sludge removal. Subsequent computed tomography revealed focal liver lesions.
View Article and Find Full Text PDFSci Total Environ
January 2025
LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address:
The presence of heavy metal(loid)s in sewage sludge is a cause of concern and an obstacle to its agricultural valorisation. This study analysed the elemental composition of sewage sludge from 42 Portuguese wastewater treatment plants (WWTPs) during summer and winter, investigating heavy metal(loid) contamination, nutrient content, and potential risks related to sludge application to agricultural soils. Levels of 8 heavy metal(loid)s were investigated, ranging from not detected (Hg) to 5120 mg kg dw (Zn), decreasing in the order Zn > Cu > Cr > Ni > Pb > As>Cd > Hg.
View Article and Find Full Text PDFFront Microbiol
January 2025
Agroécologie, French National Institute for Agriculture, Food, and Environment (INRAE), Institut Agro, Université Bourgogne, Université Bourgogne Franche-Comté, Dijon, France.
Introduction: Agriculture is undergoing an agroecological transition characterized by adopting new practices to reduce chemical fertilizer inputs. In this context, digestates are emerging as sustainable substitutes for mineral fertilizers. However, large-scale application of digestates in agricultural fields requires rigorous studies to evaluate their long-term effects on soil microbial communities, which are crucial for ecosystem functioning and resilience.
View Article and Find Full Text PDFJ Environ Manage
January 2025
Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, 610041, PR China; Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture and Rural Affairs, Chengdu, 610041, PR China. Electronic address:
To solve the problem of low chemical oxygen demand (COD)/N and poor efficiency of single-stage sequencing batch reactor (SBR) or anoxic/oxic process (A/O) in treatment of digested effluent of swine wastewater, combined SBR-A/O and A/O-SBR processes were employed in the addition ratios of 0, 10%, 30%, and 40% (V/V)) of raw swine wastewater (RS). Analysis of pollutants removal performance of SBR-A/O and A/O-SBR systems showed no significant difference between the two systems without RS addition. However, after adding RS, the pollutants removal efficiency of the two systems increased with the increase in the ratio of RS, with SBR-A/O system presenting better pollutants removal performance than A/O-SBR system.
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