There is little information in the literature to describe the effects of heavy metals on activated sludge kinetics. The purpose of this study is to evaluate the toxic effect of nickel on activated sludge. Different concentrations of Ni(II) (5.0, 10.0 and 25.0 mg l−1) were maintained in a laboratory-scale completely mixed activated-sludge unit, without recycle, treating, simulated wastewater. The feed solution contained 650 mg l−1 protein (corresponding to 1300 mg l−1 COD) as a source of carbon. Experimental results indicated that the treatment efficiency was not adversely affected by the presence of nickel up to a concentration of 10.0 mg l−1. However, a concentration of 25.0 mg l−1 Ni(II) caused serious upsets in the system, while 5.0 mg l−1 Ni(II) in feed solution had some stimulatory effects. The maximum specific growth rate, μm, of the culture also doubled when the nickel concentration was 5.0 mg l−1 and better floc formation was noticed at this nickel concentration.


SURUCU, G; Sanin, Faika Dilek (Elsevier BV, 1989-11-01)
This study investigates the effect of aeration basin temperature, pH and dissolved oxygen (DO) concentration on filterability and compressibility characteristics of activated sludge. Laboratory-scale semi-continuous reactors, fed with synthetic wastewater were used. Effects of temperatures of 15, 20, 25, 30, 35°C; pH values of 5.7, 7.2, 8.2, 9.0 and DO concentrations of 0.5, 1.0, 1.5, 2.0, 5.0 ml/l were studied by keeping all the other parameters constant in each case. Results indicated that as the operatin...
Enzymatic extraction of activated sludge extracellular polymers and implications on bioflocculation
Sesay, Ml; Özcengiz, Gülay; Sanin, Faika Dilek (Elsevier BV, 2006-04-01)
This study examines enzyme hydrolysis, a mild, effective, but a rarely used method of extracellular polymer extraction, in removing polymers from mixed culture activated sludge flocs. Two carbohydrate specific enzymes (a-amylase and cellulase) and a protein specific enzyme (proteinase) are used during the study. First, the kinetic aspect is investigated, then enzyme dose optimization is carried out on laboratory grown activated sludge samples cultured at solids retention times (SRT) of 4 and 20 days. A more...
Bioflocculation of activated sludge: The role of calcium ions and extracellular polymers
Sanin, Faika Dilek (Informa UK Limited, 2000-12-01)
In an attempt to identify the bioflocculation mechanisms, this study examines the role of calcium ions in flocculation of activated sludge. Two calcium specific chelants, ethylenebis (oxyethylenenitrilo)tetraacetic acid (EGTA) and sodium hexametaphosphate (HMT) are used to extract calcium ions. Both chemicals successfully extract the calcium ions from sludge structure, which is confirmed either by an increase in solution calcium concentration or by a decrease in calcium concentration in the sludge solid mat...
GOKCAY, CF; Yetiş, Ülkü (Elsevier BV, 1991-01-01)
Hexavalent chromium, which is frequently encountered in the tannery effluents and in the electroplating wastes, is normally considered toxic to the activated sludge culture. Often a physico-chemical pretreatment prior to biological treatment is considered necessary. However, in this study it has been shown that an acclimatized activated sludge culture is fully capable of coping with the Cr(VI)-containing wastes and moreover the culture was significantly stimulated by up to 25 mg l-1 Cr(VI). None of the t...
Toxicity of 2,4-D acid to phytoplankton
Okay, OS; Gaines, A (Elsevier BV, 1996-03-01)
The toxic effects of 2,4-D on Phaedoactylum tricornutum (Bohlin) and Dunaliella tertiolecta (Butcher), two species of phytoplankton well suited to bioassay studies and responsive to pollutants, were studied by monitoring changes in growth in terms of cell populations, chlorophyll fluorescence and the rate of (CO2)-C-14 assimilation. Short term bioassays, batch and continuous cultures were studied. Pure 2,4-D acid appeared more toxic than the commercial amine form of the herbicide but this may have been due ...
Citation Formats
Ü. Yetiş, “EFFECT OF NICKEL(II) ON ACTIVATED-SLUDGE,” WATER RESEARCH, pp. 1003–1007, 1989, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/41236.