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Sludge stabilisation
An overview of sludge stabilisation − alkaline stabilisation, lime and solids dosing, plus anaerobic and aerobic digestion
Sludge stabilisation
Stabilisation processes as applied to sludge are those which reduce its odour and putrescence (i.e. decay), and level of pathogenic organisms. This is generally achieved either chemically or biologically.
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About sludge stabilisation
Stabilisation processes reduce the odour and putrescence of sludge, and level of pathogenic organisms
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Sludge treatment − alkaline stabilisation
Alkaline stabilisation is a chemical method to reduce sludge odour and putrescence, and the level of pathogenic organisms
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Sludge treatment − lime and solids dosing
Chemical stabilisation of sludge reduces its odour, putrescence and pathogenic bacteria content
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Anaerobic digestion
An overview of anaerobic digestion − an introduction to sludge processing AD theory
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Sludge treatment - the anaerobic digestion process
Anaerobic digestion (AD) is the most extensively employed sludge stabilisation process, and generates a methane gas product
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Sludge treatment − how does anaerobic digestion work?
Anaerobic digestion is a multi-step biochemical process comprising hydrolysis, acidogenesis, acetogenesis and methanogenesis
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Designing anaerobic digestion systems for sludge treatment
Anaerobic digestion can be a single or multiple tank process, and employ different conditions of stirring and temperature
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Sludge pretreatment for anaerobic digestion
Pretreating sludge upstream of the anaerobic digestion is sometimes carried out to improve the sludge biological treatability
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Operating an anaerobic digester for sludge treatment
Anaerobic digestion can be conducted at moderate (mesophilic) or elevated (thermophilic) temperature conditions
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Challenges to anaerobic digestion in sludge treatment
Two widely recognised operational challenges to anaerobic digestion operation are foaming and over-acidification
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Managing anaerobic digestion biogas in sludge treatment
Anaerobic digestion generates a biogas containing 50-60% methane which can be used to generate heat and electrical power
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Managing anaerobic digestion digestate in sludge treatment
The digestate is the residual slurry, containing up to 20% solids, generated from the anaerobic digestion process
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Managing anaerobic digestion supernatant in sludge treatment
The supernatant is the liquid stream generated from anaerobic digestion process and has a high nutrient content
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Aerobic digestion
An overview of aerobic digestion and sludge composting
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Sludge treatment − an overview of aerobic digestion
Aerobic digestion is the degradation of the organic sludge solids in the presence of oxygen
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Sludge treatment − composting
Composting is a type of aerobic digestion. The most established method for composting is through the use of windrows
Sludge stabilisation related videos
Conventional activated sludge (CAS) process
Aerobic wastewater treatment with classical activated sludge. A taster for Judd Water & Wastewater Consultants' 'MBR Insights' training package, in this video Simon Judd explains classical aerobic wastewater treatment.
Sludge stabilisation 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 Sludge stabilisation topics…
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Alkaline stabilisation
Alkaline stabilisation reduces the sludge odour, putrescence and pathogenic organism content by raising its pH using lime
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Anaerobic digestion
AD stabilises the sludge biologically in the absence of air, producing a useful biogas while biodegrading the organic solids
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Aerobic digestion
Aerobic digestion is the degradation of the organic sludge solids to carbon dioxide in the presence of oxygen
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Alkaline stabilisation
Alkaline stabilisation reduces the sludge odour, putrescence and pathogenic organism content by raising its pH using lime
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Anaerobic digestion
AD stabilises the sludge biologically in the absence of air, producing a useful biogas while biodegrading the organic solids
-
Aerobic digestion
Aerobic digestion is the degradation of the organic sludge solids to carbon dioxide in the presence of oxygen
More process and operation topics…
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Thickening, dewatering & drying
Thickening, dewatering and drying extract water from sludge to reduce the sludge volume
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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