Sludge

Sludge is a semi-solid slurry that can be produced from a range of industrial processes, from water treatment, wastewater treatment or on-site sanitation systems. For example, it can be produced as a settled suspension obtained from conventional drinking water treatment,^[1] as sewage sludge from wastewater treatment processes^[2]^: 23–25 or as fecal sludge from pit latrines and septic tanks. The term is also sometimes used as a generic term for solids separated from suspension in a liquid; this 'soupy' material usually contains significant quantities of 'interstitial' water (between the solid particles). Sludge can consist of a variety of particles, such as animal manure.^[3]

Industrial wastewater treatment plants produce solids that are also referred to as sludge. This can be generated from biological or physical-chemical processes.

In the activated sludge process for wastewater treatment, the terms "waste activated sludge" and "return activated sludge" are used.

In food processing and beverage-making industries, sludge can have high protein content and other nutrients that can be used for beneficial purposes such as animal feed, thereby avoiding disposal at a landfill.

References

^ Edzwald, James K., ed. (2011). Water Quality and Treatment (6th ed.). McGraw-Hill. ISBN 978-0-07-163011-5.
^ Tchobanoglous, George; Burton, Franklin Louis; Stensel, H. David; Metcalf & Eddy (2003). Wastewater Engineering: Treatment and Reuse (4th ed.). McGraw Hill. ISBN 9780071122504.
^ Byfield, Mike (July 7, 1997). "Farmers line up for their slug of pulp sludge". Alberta Newsprint Co.

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[1] Edzwald, James K., ed. (2011). Water Quality and Treatment (6th ed.). McGraw-Hill. ISBN 978-0-07-163011-5.

[2] Tchobanoglous, George; Burton, Franklin Louis; Stensel, H. David; Metcalf & Eddy (2003). Wastewater Engineering: Treatment and Reuse (4th ed.). McGraw Hill. ISBN 9780071122504.

[3] Byfield, Mike (July 7, 1997). "Farmers line up for their slug of pulp sludge". Alberta Newsprint Co.

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v t e Wastewater
Sources and types	Acid mine drainage Ballast water Bathroom Blackwater (coal) Blackwater (waste) Boiler blowdown Brine Combined sewer Cooling tower Cooling water Fecal sludge Greywater Infiltration/Inflow Industrial wastewater Ion exchange Leachate Manure Papermaking Produced water Return flow Reverse osmosis Sanitary sewer Septage Sewage Sewage sludge Toilet Urban runoff
Quality indicators	Adsorbable organic halides Biochemical oxygen demand Chemical oxygen demand Coliform index Oxygen saturation Heavy metals pH Salinity Temperature Total dissolved solids Total suspended solids Turbidity Wastewater surveillance
Treatment options	Activated sludge Aerated lagoon Agricultural wastewater treatment API oil–water separator Carbon filtering Chlorination Clarifier Constructed wetland Decentralized wastewater system Extended aeration Facultative lagoon Fecal sludge management Filtration Imhoff tank Industrial wastewater treatment Ion exchange Membrane bioreactor Reverse osmosis Rotating biological contactor Secondary treatment Sedimentation Septic tank Settling basin Sewage sludge treatment Sewage treatment Sewer mining Stabilization pond Trickling filter Ultraviolet germicidal irradiation UASB Vermifilter Wastewater treatment plant
Disposal options	Combined sewer Evaporation pond Groundwater recharge Infiltration basin Injection well Irrigation Marine dumping Marine outfall Reclaimed water Sanitary sewer Septic drain field Sewage farm Storm drain Surface runoff Vacuum sewer
Category: Sewerage