Municipal sludge is difficult to treat and dispose of because of its high moisture content (MC) and volume. In this study, a novel dewatering method that utilizes ultrahigh pressure filtration (UHPF) and thin-cake-press (TCP) coupled with microwave pretreatment was proposed to reduce the MC of sludge cake. The influence of microwave contact time (MCT), microwave intensity (MI), initial MC of sludge, dewatering time, applied pressure and sludge weight (Ws) on the MC of a sludge cake was investigated by the single-factor experiment. Moreover, a water discharge path model was developed to understand the dewatering mechanism and explain the relationship between thickness and MC of the cake. The key factors affecting the MC of the cake were explored by the orthogonal experiment. The experimental results showed that microwave irradiation could effectively improve the dewatering performance and reduce the MC of the sludge cake. The MC of the cake reached its lowest value of 28% at MCT of 120 s and MI of 400 W, which is much lower than the value obtained by the traditional dewatering method. Among the parameters mentioned above, Ws has the most significant influence on MC because a large amount of sludge leads to a thicker cake, which seriously hampers the flow of filtrate and inevitably increases the MC of the cake.
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http://dx.doi.org/10.1016/j.jenvman.2019.06.118 | DOI Listing |
Chemosphere
February 2025
Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, United States. Electronic address:
In agricultural and waste management systems, dairy manure wastewater is often recycled for irrigation. However, a key challenge lies in handling suspended solids (SS) and effectively dewatering sludge. To address this, an innovative polycationic soybean protein-based flocculant (SPI+) was developed and applied to enhance flocculation and sludge dewatering efficiency.
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February 2025
School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran.
This study evaluated the integration of electrocoagulation into a lab-scale membrane bioreactor (EC-MBR) for treating wastewater from a detergent manufacturing plant. The EC-MBR system achieved a higher chemical oxygen demand (COD) and anionic surfactant removal efficiencies of 95.1% and 99.
View Article and Find Full Text PDFEnviron Sci Technol
December 2024
State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), Beijing Key Laboratory for Emerging Organic Contaminants Control, School of Environment, Tsinghua University, Beijing 100084, China.
The electroplating industry is an important source of per- and polyfluoroalkyl substances (PFAS) contamination, but there is a lack of comprehensive studies on the occurrence, transport, and removal of PFAS in electroplating parks. In this study, we investigated typical electroplating parks in China and conducted the first full-scale removal of PFAS from chromium-plating wastewater using pore-enlarged granular activated carbon (GAC) and hydrophobic anion exchange resin (AER). The results showed that 6:2 fluorotelomer sulfonate (6:2 FTS) gradually replaced perfluorooctanesulfonate (PFOS) in China's electroplating industry.
View Article and Find Full Text PDFWater Res
March 2025
TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France - 135 avenue de Rangueil, 31077 Toulouse CEDEX 04, France.
In a municipal wastewater treatment plant, the thermal treatment of sludge can be an efficient way of increasing the final sludge cake dryness and boosting anaerobic digestion performances. However, such treatments generate refractory compounds which, once returned to headworks, can affect the quality compliance of effluent discharges, particularly concerning organic nitrogen. This study explores the effects of thermal hydrolysis (TH) and hydrothermal carbonization (HTC) of municipal sludge on the refractory organic compound production.
View Article and Find Full Text PDFWater Res
February 2025
Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Center of Wastewater Resource Reuse, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China. Electronic address:
The effective treatment of food waste digestate is critical for reducing environmental pollution and mitigating carbon emissions, with deep dewatering playing a pivotal role. Conventional dewatering agents such as polyaluminum chloride (PAC) and polyacrylamide (PAM), commonly employed in municipal sludge treatment, exhibit limited efficacy when applied to food waste digestate due to the latter's high salinity and advanced fermentation stages. This study introduces polyethylene oxide (PEO) as a novel conditioning agent and investigates its dewatering performance in comparison to PAC and PAM, elucidating the underlying mechanism.
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