The role of calcium ion on activated sludge biochemical and physical properties in phosphorus deficient growth medium

Download
index.pdf
2010
Aksu, Ceren
Show full item record
185
views
53
downloads
Nutrients and cations have significant effect on activated sludge characteristics and therefore effect the efficiency of whole processes. To determine the properties in phosphorus deficient medium and the effect of calcium ions two reactor sets with two different phosphorus concentration (C/N/P=100/5/0.05 and C/N/P=100/5/1), three different concentrations of calcium (0.5, 5, 15 meq/L) were operated with 8 days of sludge residence time and an effective volume of 2 L. Results showed amount and composition of EPS was dependent on calcium and phosphorus concentrations. Except for the highest calcium concentration, increase in phosphorus concentration resulted in increase in total EPS production. Under phosphorus deficient conditions, calcium ions stimulated the production of carbohydrate type polymers and viscous bulking was observed. However, the increase in phosphorus concentration led to increase in protein type polymer production and bulking condition was cured. Addition of calcium ions increased conductivity in both cases, but increase in phosphorus concentration caused decrease in conductivity. Increase in phosphorus concentration had improved settleability, dewaterability and rheology of sludge. Moreover, effluent turbidity was decreased and COD removal efficiency was recorded as greater than 95 % for all calcium concentrations under phosphorus sufficient conditions. Microscopic analyses showed that under phosphorus deficient conditions flocs were weak, dispersed and nonresistant. Increase in phosphorus concentration resulted in improvement of floc structure. Same Enterobacter and Citrobacter species were identified at all calcium concentrations under phosphorus deficient conditions. Yet, under phosphorus sufficient conditions different species were identified in control reactor as compared to 5 meq/L and 15 meq/L concentrations.
Calcium ions
http://etd.lib.metu.edu.tr/upload/12612580/index.pdf
https://hdl.handle.net/11511/20182
Graduate School of Natural and Applied Sciences, Thesis

Suggestions

On the Electrochemical Reduction Mechanism of CaWO4 to W Powder
Erdogan, Metehan; Karakaya, İshak (2012-08-01)
The reduction mechanism of CaWO4 to W in molten eutectic CaCl2-NaCl electrolyte has been studied. Cyclic voltammetry and constant potential electrolysis tests were performed to determine the reversible cell potential. Analyses of the experimental results revealed that at least 2.2 V was required to compensate the potentials for the accompanying cell reaction and the electrode polarizations. A cell reaction was proposed by associating the experimental results and the Gibbs energy changes of the possible reac...
The Effects of Co-Mo/CaCO3 Catalyst's Calcination Temperature and Co/Mo Weight Ratio on Carbon Nanotube Production
Hocaoglu, Caner; Sezgi, Naime Aslı (2015-01-01)
Carbon nanotubes (CNTs) were synthesized in the temperature range of 500-700 degrees C over cobalt (Co)- and molybdenum (Mo)impregnated CaCO3 catalysts using acetylene gas. The effects of Co-Mo/CaCO3 catalyst's calcination temperature and Co/Mo weight ratio on the carbon deposition rate were investigated. The synthesized CNTs were multiwalled nanotubes with variable outer diameters. They exhibited Type II isotherm, and their surface areas were in the range of 24.8-89.9m(2)/g. It was concluded that the Co/Mo...
The influence of nutrient loading, climate and water depth on nitrogen and phosphorus loss in shallow lakes: a pan-European mesocosm experiment
Coppens, Jan; Hejzlar, Josef; Sorf, Michal; Jeppesen, Erik; Erdogan, Aeyda; Scharfenberger, Ulrike; Mahdy, Aldoushy; Noges, Peeter; Tuvikene, Arvo; Baho, Didier L.; Trigal, Cristina; Papastergiadou, Eva; Stefanidis, Kostas; Olsen, Saara; Beklioğlu, Meryem (2016-09-01)
Losses of phosphorus (P) and nitrogen (N) have important influences on in-lake concentrations and nutrient loading to downstream ecosystems. We performed a series of mesocosm experiments along a latitudinal gradient from Sweden to Greece to investigate the factors influencing N and P loss under different climatic conditions. In six countries, a standardised mesocosm experiment with two water depths and two nutrient levels was conducted concurrently between May and November 2011. Our results showed external ...
Synthesis and applications of ion incorporated amorphous calcium-magnesium carbonate
Göçtü, Yağmur; Ercan, Batur; Department of Metallurgical and Materials Engineering (2023-1-18)
Amorphous calcium carbonate (ACC) can be synthesized using co-precipitation technique and different ions can typically be incorporated into its amorphous structure to enhance its stability. Although ACC was investigated for various applications, its antibacterial properties have not been explored. In this thesis, two different types of magnesium stabilized amorphous calcium carbonate (ACMC) nanoparticles were synthesized for antibacterial applications. In the first part selenite ions, and in the secon...
The effect of dissolved species on hydrophobic aggregation of fluorite
Hicyilmaz, C; Bilgen, S; Ozbas, KE (1997-03-10)
The hydrophobic aggregation of fluorite in the presence of Fe3+, Al3+, F- Ca2+, Mg2+ and Ba2+ ions was studied. Electrokinetic potentials were measured to interpret the effect of these ions on aggregation.
Citation Formats
C. Aksu, “The role of calcium ion on activated sludge biochemical and physical properties in phosphorus deficient growth medium,” M.S. - Master of Science, Middle East Technical University, 2010.
METU IIS - Integrated Information Service open@metu.edu.tr