Topic
Sludge separation − filtration
Filtration theory defines the way in which water flows through the bed, which is formed of the sludge solids (cake)
Drying beds
Sludge drying beds provide sludge dewatering by allowing the liquid to both drain under gravity through a permeable medium on which the sludge sits, and to evaporate under ambient conditions. The sludge is spread as a thin (up to 300 mm) layer over a porous bed made up of layers of sand and gravel.
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Sludge dewatering
An overview of sludge dewatering − an introduction to sludge dewatering theory and technologies
Topic
Introduction to sludge dewatering
Dewatering processes provide a concentrated, consolidated product along with a diluted stream which is predominantly water
Topic
Sludge drying beds and lagoons
Drying beds dewater sludge by allowing the liquid to drain and to evaporate. Lagoons provide dewatering through evaporation
Drying beds related videos
Sludge solids separation theory
Sludge solids separation theory − a brief introduction to the theories around sludge sedimentation, cake filtration and cake compression.
Drying beds features and blogs
Feature
Co-processing of sewage digestate by hydrothermal carbonisation
Hydrothermal carbonisation (HTC) can be used to co-process anaerobic digestion (AD) digestate and lignocellulosic (or plant-based) feedstocks to improve the the hydrochar product quality. This AD waste co-processing route has been studied at bench scale. Read article
More Drying beds topics…
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Belt filter presses
A belt filter press (BFP) dewaters sludge by pressing it between two revolving permeable belts to squeeze out the water
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Centrifuges
Centrifugal dewatering consolidates sludge by encouraging particles to migrate to the walls of a rapidly rotating cyclinder
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Filter presses
A filter press dewaters sludge by pressing it between a series of porous plates at high pressure to squeeze out the water
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Lagoons
A lagoon is a large shallow reservoir filled with sludge, which settles and stabilises over an extended time period
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Rotary press
A rotary press dewaters sludge by passing it along a channel formed between two slowly-rotating circular permeable screens
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Screw presses
A screw press dewaters sludge by passing it along the inside of an inclined permeable cylinder using an Archimedean screw
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Conditioning
Conditioning is the pretreatment of sludge upstream of thickening and dewatering to promote solid-liquid separation
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Thickening
Thickening processes concentrate the sludge by removing part of the free water, such that the product can still be pumped
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Dewatering
Dewatering processes mechanically remove a significant proportion of the sludge water to produce a 15-45% cake product
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Drying
In sludge drying the sludge moisture is removed as water vapour by heating, generating a pelleted or powdered product
More process and operation topics…
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Sludge stabilisation
Sludge stabilisation − alkaline stabilisation, lime and solids dosing, plus anaerobic and aerobic digestion
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Thermochemical processes
Thermochemical methods are used to either significantly reduce the sludge solids content or pre-treat sludge upstream of AD
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Sludge quality
Sludge is the main waste stream from the treatment of wastewater