Investigation of activated sludge bioflocculation : influence of magnesium ions

Download

index.pdf

Date

2005

Author

Turtin, İpek

Metadata

Show full item record

Item Usage Stats

336
views

175
downloads

Activated sludge systems are the most widely used biological wastewater treatment processes all over the world. The main working principles of an activated sludge system are the oxidation of biologically degradable wastes by microorganisms and the subsequent separation of the newly formed biomass from the treated effluent. Separation by settling is the most troublesome stage of an activated sludge process. A decrease in the efficiency of the separation of microbial biomass from the treated effluent causes a decrease in the overall efficiency of the treatment plant. The efficiency of the separation process is related to the bioflocculation, which can be briefly defined as the aggregation of the bacteria into flocs through flocculation. Bioflocculation depends on the extracellular polymers (EPS) that are produced by microorganisms. The operating conditions of the activated sludge system is a key determinant of the synthesis of EPS and bioflocculation. The main objective of this study is to find out the effect of magnesium ions on the bioflocculation process under phosphorus deficient and sufficient conditions. In order to achieve this aim, the effects of magnesium ion in 4 different concentrations (0.9, 5, 10 and 20 meq/L) are investigated in semi continuous reactors. The reactors are operated at a mean cell residence time of 8 days and 20ð C temperature. When reactors are confirmed to be at steady state, several sets of analysis are conducted. In particular, the surface chemical parameters including EPS and its components, electrical charge, and hydrophobicity as well as physical properties such as settlability, filterability, viscosity, floc strength, and turbidity are examined. It has been understood that phosphorus deficiency causes severe filamentous bulking under magnesium rich conditions. Increasing the phosphorus concentration in the influent can cure this

Subject Keywords

Sewage collection.

URI

http://etd.lib.metu.edu.tr/upload/2/12606605/index.pdf
https://hdl.handle.net/11511/15560

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Effects of ultrasound pretreatment and anaerobic digestion on the energy potential of sludge Çelebi, Emrehan Berkay; Sanin, Faika Dilek; Aksoy, Ayşegül; Department of Environmental Engineering (2015) The by-product of wastewater treatment, sludge, is generated in tons everyday all around the world. As environmental regulations in Turkey are becoming stricter during the European Union adaptation period, the previously wide-spread disposal method of landfilling the sludge will not be applicable. Instead, dried sludge is expected to be used in revenue generating methods like land application or combustion. Combustion can be thought of as more beneficial as it uses sludge as an energy source. However, it is...
Effect of extracellular polymer composition of activated sludge on the removal of heavy metals by biosorption Yüncü, Bilgen; Yetiş, Ülkü; Sanin, F. Dilek; Department of Environmental Engineering (2003) Activated sludge microorganisms can remove many hazardous substances from wastewater by adsorbing and concentrating them on their surfaces. Biosorption of these substances onto activated sludge surfaces are influenced by the chemical properties of the substance in question as well as the surface properties of the microorganisms. The purpose of this study is to identify the biosorption mechanisms of heavy metals and the effect of extracellular polymer (ECP) composition of activated sludge on the biosorption ...
Modeling of carbon dioxide sequestration in a deep saline aquifer Başbuğ, Başar; Gümrah, Fevzi; Department of Petroleum and Natural Gas Engineering (2005) CO2 is one of the hazardous greenhouse gases causing significant changes in the environment. The sequestering CO2 in a suitable geological medium can be a feasible method to avoid the negative effects of CO2 emissions in the atmosphere. CO2 sequestration is the capture of, separation, and long-term storage of CO2 in underground geological environments. A case study was simulated regarding the CO2 sequestration in a deep saline aquifer. The compositional numerical model (GEM) of the CMG software was used to ...
Treatment and valorization of anaerobic digestate Ülgüdür, Nilüfer; Bayramoğlu, Tuba Hande; Demirer, Göksel Niyazi; Department of Environmental Engineering (2019) Anaerobic digestion is a widely applied process for the stabilization and treatment of high-strength wastes. The process has two outputs, biogas and digestate. Even though biogas produced during the treatment is a renewable energy source and has positive impacts on improving the economics of the plant, the treatment and disposal of the digestates present a challenge. The treatment methods offered so far are either costly or low yielded which drives off these uneconomic and non-viable treatment processes fro...
Investigation of influent COD/TAN ratio and loading rate effects on carbon and nitrogen removal via aerobic granules Kocatürk, İrem; Bayramoğlu, Tuba Hande; Department of Environmental Engineering (2014) Aerobic granulation serves as a promising treatment technology over the conventional systems due to its advantages such as high biomass retention capacity, high settleability, ease of separation from the effluent, toxicity resistance, capacity to handle high organic loading rates and suitability for high chemical oxygen demand (COD) wastewaters. The scope of the thesis is to investigate the influent COD/total ammonifiable nitrogen (TAN = NH4-N + NH3-N) ratio and loading rate effects for the removal of carbo...

Citation Formats

İ. Turtin, “Investigation of activated sludge bioflocculation : influence of magnesium ions ,” M.S. - Master of Science, Middle East Technical University, 2005.