activated sludge

Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.
Related to activated sludge: Trickling filter, activated sludge method

ac·ti·vat·ed sludge meth·od

a method of sewage disposal in which sewage is treated with 15% bacterially active liquid sludge, which is produced by repeated vigorous aeration of fresh sewage to form floccules or sediment; when this flocculation process is complete, the resulting activated sludge contains large numbers of bacteria, together with yeasts, molds, and protozoa, which actively effect the oxidation of organic compounds; this mixture is piped to a sedimentation tank, the effluent from which is completely treated sewage.

activated sludge

any living material used in sewage treatment, consisting mainly of bacteria and protozoans, that breaks down organic matter in the sewage and increases by multiplication during the process. Part of the new sludge is used in the continuing treatment of the sewage.


a state of being more than usually active. In biological systems this is usually brought about by chemical or electrical means. Commonly said of pharmaceutical and chemical products.

activated clotting time (ACT)
a simplified version of the activated partial thromboplastin time which measures the intrinsic clotting activity of the whole blood. See also activated coagulation time, clotting time.
activated partial thromboplastin time (APTT)
a test of intrinsic clotting activity of whole blood. Partial prothrombin, usually rabbit or human brain prothrombins, is added to plasma activated with kaolin or ellagic acid. The time required for the test is short and the results are dependable.
activated sludge
a method of dealing with sewage and abattoir effluent. Consists of an aeration tank in which biologically active, previously sedimented sludge is mixed with incoming effluent and agitated in the presence of an ample supply of air.


a suspension of solid or semisolid particles in a fluid.

activated sludge
a means of encouraging biodegradation. See also activated sludge.
References in periodicals archive ?
Biological sludge was collected from the rubber industry of Shorubber (M) Sdn Bhd in Jejawi, Perlis which has extended aeration activated sludge plant.
American industrial wastewater specialists Eckenfelder, who died in 2010 while working on this book, and Cleary explain to operators, engineers, and students some recent developments in the activated sludge biological treatment of industrial wastewater.
Many studies and investigations have shown that the percentage removal of parasites egg in trickling filter, aerated lagoon, activated sludge and both stabilization ponds and artificial wetlands have respectively reached to the level of 99%, 99.
The benefits of the CFAS[R] (IFAS) include a compact design, doubling the capacity of an existing activated sludge plant.
The respiration rate of activated sludge is an important variable for the control of activated sludge process, because oxygen consumption is directly associated with both biomass growth and substrate removal [20].
Gokcay (1989) have reported that the substrate removal efficiency of acclimatized activated sludge process was not adversely affected by the presence of [Ni.
Chapters are then devoted to specific categories of value-added sludge products, such as biosurfactants, bioplastics from activated sludge, bioflocculants, biopesticides, biofertilizers and bioinoculants, and production and extraction of enzymes.
During the test period, aerobic digested sludge's pH was almost neutral and the returned activated sludge had a very poor acidic property (pH=6.
Oseltamivir carboxylate (OC), Tamiflu's active metabolite, is known to withstand activated sludge treatment at sewage treatment plants (STPs), but less is known about how much OC may make its way into waterways that receive STP effluent.
An automated screen system will be used for mechanical pre-treatment while an activated sludge system is to be employed for biological treatment.
The pollution was from activated sludge, which is used in the sewage treatment process.

Full browser ?