Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment
Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment
tThe University ofNottinghamThe University of NottinghamSchool of Chemical and Environmental EngineeringBIOFLOCCULATION AND FINAL PROPERTIESOF SYNTHET Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment TIC AND ACTIVATED SLUDGE IN WASTEWATER TREATMENTTan Phong Nguyen (BEng, ME ng)Thesis submitted to the School of Chemical and Environmental Engineering in partial fulfilment of the requirements for the degree ofDoctor of Philosophy2008SUMMARYTile activated sludge flocculation IS a very complex proces Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment s ill which many factors interact and may have an influence. Since a large number of these influences are poorly understood, the characteristics relatBioflocculation and final properties of synthetic and activated sludge in wastewater treatment
ed to the floc-formation are still difficult to be predicted and controlled. This work aimed to improve knowledge on the flocculation process with partThe University ofNottinghamThe University of NottinghamSchool of Chemical and Environmental EngineeringBIOFLOCCULATION AND FINAL PROPERTIESOF SYNTHET Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment on dynamics and sludge settling, dewatering, and conditioning since it is an essential requirement for an optimal biological wastewatei treatment.Synthetic sludge is made up of nonliving particles that resemble activated sludge components. The components of synthetic sludge include: polystyrene late Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment x particles of bacterial size, which simulate individual bacteria: alginate simulates extracellular polymeric substances: fibrous cellulose is used toBioflocculation and final properties of synthetic and activated sludge in wastewater treatment
simulate the filamentous microorganisms found ill activated sludge: and calcium ions are used as bridging cations.The first part of this thesis was itThe University ofNottinghamThe University of NottinghamSchool of Chemical and Environmental EngineeringBIOFLOCCULATION AND FINAL PROPERTIESOF SYNTHET Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment es. A laboratory-scale batch reactor, fed with standard synthetic sludges was used. The effects of varying calcium concentration (5-25111M). alginate concentration (25-125mg'L). fibrous cellulose concentration (1.0-1.8g L) and pH (3-9) on the sludge characteristics were studied by varying one parame Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment ter whilst keeping the others constant The results from experiments indicated that the calcium, alginate, fibrous cellulose, and pH had the critical eBioflocculation and final properties of synthetic and activated sludge in wastewater treatment
ffect on the aggregation rate, flocs size, andiimade (he improvement of (lie final properties of sludge. Dynamic measurements have established rhe opttThe University ofNottinghamThe University of NottinghamSchool of Chemical and Environmental EngineeringBIOFLOCCULATION AND FINAL PROPERTIESOF SYNTHET Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment h measurements of settleability and turbidity of the synthetic activated sludge. The results of this study support the bonding theory and indicate that formation of cations* polymer complexes and polymer gelation are important means of flocculation.The second part of this thesis was a comparative st Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment udy has been made to investigate 111 fashion the flocculation behaviour and final properties of both synthetic and activated sludge. Activated sludgeBioflocculation and final properties of synthetic and activated sludge in wastewater treatment
was produced 111 a lab-scale. The novelty of this approach lies in the attempt to use the former as a key to characterising the physical and chemical tThe University ofNottinghamThe University of NottinghamSchool of Chemical and Environmental EngineeringBIOFLOCCULATION AND FINAL PROPERTIESOF SYNTHET Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment ic dispersion analyser (PDA). The Malvern Mastersizer-S was selected to measure the floc size and size distribution: the effects of calcium, aluminium. polysaccharide, fibrous cellulose, polyelectrolyte conditioner and shear rate on final sludge properties were determined, including settleability, t Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment urbidity of supernatant, sludge volume index and dewatering, sludge conditioning, floc strength, and floc structure. It was thus possible to link theBioflocculation and final properties of synthetic and activated sludge in wastewater treatment
flocculation dynamics to the final sludge properties.The results indicate that calcium ions and polysaccharide play an important role in the floc formtThe University ofNottinghamThe University of NottinghamSchool of Chemical and Environmental EngineeringBIOFLOCCULATION AND FINAL PROPERTIESOF SYNTHET Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment al properties of the sludge. A qualitative link exists between the flocculation dynamics and the final properties for both types of sludge, and between the floc dynamics and properties ofiiisynthetic sludge on the one hand and those of activated sludge on the other. The two types of sludge have very Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment similar settling and dewatering characteristics after cationic polymer conditioning. However, there are quantitative differences 111 the calcium concBioflocculation and final properties of synthetic and activated sludge in wastewater treatment
entration required for flocculation, the supernatant turbidity, the sludge-volume index and the floc strength. This difference IS believed to be due ttThe University ofNottinghamThe University of NottinghamSchool of Chemical and Environmental EngineeringBIOFLOCCULATION AND FINAL PROPERTIESOF SYNTHET Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment ic sludge makes it useful as a noncomplex analogue for the physical and chemical properties of activated sludge.The relationship between polysaccharide concentration and cation concentration was examined at laboratory scale during flocculation with both synthetic and activated sludge; an increase in Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment feed cation concentration led to a decrease in final polysaccharide concentration. An increase 111 cation concentration ill the feed to the reactorsBioflocculation and final properties of synthetic and activated sludge in wastewater treatment
was also associated with an increase in the bound biopolymer concentration. The changes in the bound biopolymer were explained according to the cationtThe University ofNottinghamThe University of NottinghamSchool of Chemical and Environmental EngineeringBIOFLOCCULATION AND FINAL PROPERTIESOF SYNTHET Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment udge can be used as a surrogate in activated sludge studies. The results of this work also indicate that the formation of cation-polymer complexes and polymer gelation are amongst the most important mechanisms for sludge coagulation-flocculation, and offer a means for optimisation of the activated s Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment ludge process.The third part of this thesis was examination of microorganisms consortium existing in activated sludge and specific oxygen uptake ratesBioflocculation and final properties of synthetic and activated sludge in wastewater treatment
(SOUR). Beside the conventional method, a new identification method called ‘API 20E' was adapted to examine theivmicroorganism consortium existing intThe University ofNottinghamThe University of NottinghamSchool of Chemical and Environmental EngineeringBIOFLOCCULATION AND FINAL PROPERTIESOF SYNTHET Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment ted. The results showed the use of microscopic examination and the SOUR test are invaluable tools in troubleshooting the activated sludge process.The last pan of this thesis aimed at investigating the process response to variations of different physical-chemical factors. Finally, the joint effect of Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment these parameters was investigated. To this end. Design of Experiment (DOE) and Response Surface Methodology (RMS) approaches were used The knowledgeBioflocculation and final properties of synthetic and activated sludge in wastewater treatment
of resulting from this systematic study was used to explain the behaviour of a set of process characteristics.For a correct evaluation of the influenctThe University ofNottinghamThe University of NottinghamSchool of Chemical and Environmental EngineeringBIOFLOCCULATION AND FINAL PROPERTIESOF SYNTHET Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment mplete mixed activated sludge reactor was built and opeiated under stable environmental conditions.For evaluating the flocculation dynamics, an experimental set-up was built. It consisted 111 a five-litre reactor in which the flocculation process took place. Different environmental conditions were a Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment pplied in the reactor and their effect was monitor at the end of each experiment. A number of 62 experiments were performed by following an orthogonalBioflocculation and final properties of synthetic and activated sludge in wastewater treatment
and rotatable DOE The influence of four relevant factors (sludge age. organic loading rate (COD), calcium and dissolved oxygen concentration) on a setThe University ofNottinghamThe University of NottinghamSchool of Chemical and Environmental EngineeringBIOFLOCCULATION AND FINAL PROPERTIESOF SYNTHET Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment fect of all four factors on the considered set of responses was investigated by building response surface models based on the data collected from the DOE. The interaction effects between all four factors were quantified as well. Furthermore, identification of a set of factor values that optimise the Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment responses was carried out. according to specified optimisation criteria. Acceptable statistical models were generally obtained, which predicted the rBioflocculation and final properties of synthetic and activated sludge in wastewater treatment
esponse variations well The RSM analysis showed that a very good accuracy was found for COD removal rate. The COD loading rate and DO concentration shtThe University ofNottinghamThe University of NottinghamSchool of Chemical and Environmental EngineeringBIOFLOCCULATION AND FINAL PROPERTIESOF SYNTHET Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment sampling errors. which resulted 111 a high variability. The most significant factors affecting the SVI were found to lie the COD loading rate and Ca addition The model predicted that SRT and Ca addition are mainly significant factors responsible for decrease 111 TSS of supernatant. A link between th Bioflocculation and final properties of synthetic and activated sludge in wastewater treatment e effects predicted by the RSM models obtained foi the supernatant turbidity indicated that a response minimum is obtained for high SRT and high calciBioflocculation and final properties of synthetic and activated sludge in wastewater treatment
um concentrations.A process optimisation by using the RSM was performed for particular case of complete mixed activated sludge. Its goal was to find tGọi ngay
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