The use of staged scouring aeration to reduce energy for membrane fouling was studied using one pilot-scale submerged membrane bioreactor to treat municipal wastewater. The experiments were conducted by varying each of permeate fluxes, scouring air scouring intensities and sequence during both permeation and relaxation periods while keeping other factors same. The critical and recoverable fluxes were measured by the stepwise flux method. Mixed liquor, permeate and filtrate was characterized by analysing COD, cTOC, SMP contents, etc. The recorded transmembrane pressure data were used to calculate the fouling resistance after relaxation and fouling rate of each cycle. The results showed that when operated at relatively high permeate flux rate, membrane fouling could be effectively controlled by using relatively lower air scouring intensity and/or less infrequent aeration sequence during the permeation combined subsequently with more vigorous and frequent air scouring during the relaxation. At lower permeate flux rate with good permeability sludge, membrane fouling was effectively controlled by relatively low air scouring intensity and/or relatively infrequent aeration sequence during both permeation and relaxation periods. For each sludge condition, an optimal combination of cyclic air scouring intensity and sequence existed which could minimize the aeration energy consumption while maintaining effective fouling control. The frequency of aeration sequence plays a more dominant role than the air scouring intensity during the permeation in aeration optimization. / GE Water & Process Technologies Natural Sciences and Engineering Research Council of Canada

In Manitoba there are an estimated 200 small and 10 large wastewater treatment systems contributing nutrients to surface water when effluent is discharged. The objective of this study was to assess the sustainability and social acceptance of wastewater irrigation in the southeast Interlake region. It was concluded that sustainably irrigating forage crops would be challenging. The combination of soils with only ratings of fair for irrigability and the low quality of wastewater limits the long term sustainability of irrigation. Only one study site maintains a high potential to develop a wastewater irrigation program due to sufficient suitable land and appropriate wastewater quality. The social acceptance of wastewater irrigation is mixed with only about half the survey respondents favourable to irrigation or reuse of wastewater.

The reuse of domestic greywater for toilet flushing has the potential to reduce both water consumption and wastewater production, but there is a need for low-cost, low-maintenance greywater treatment systems that can meet reclaimed water quality standards. The purpose of this thesis is to develop a horizontal subsurface flow wetland design that can be sited in a greenhouse, to document the initial performance of the design treating real greywater, to determine the effect of plants, and to provide recommendations for design. Pilot wetlands (planted and unplanted replicates) were constructed in a passively heated greenhouse and fed real domestic greywater. Effluent quality was compared to national reclaimed water quality guidelines. After the first five months of the study, operational changes (reduced loading, aeration of influent, fill and drain) were tested to determine their effect on effluent quality. The results show that the original design basis, 7.5 gBOD m-2d-1, is not appropriate for greywater wetland design under the conditions of this study due to insufficient removal of BOD and turbidity (although suspended solids removal was acceptable). Anoxic conditions within the wetlands led to reduction of sulfate to hydrogen sulfide, which demands oxygen and leads to odour and turbidity problems. Plants did not affect treatment during the first five months. Aerating influent and operation in fill and drain mode may improve BOD removal at relatively high hydraulic loading rates, but effluent disinfection is required to completely remove E.coli. Design recommendations were developed, including tentative loading rates and plant species. / Ontario Centres of Excellence, NSERC

No description available.

The objective of this study was to provide a technique, based on the residence time distribution of a process, for modelling, assessing and improving flow in the processes of water and waste water treatment works. The technique should be accessible to the staff managing and operating the works. From a review of the literature, a preference was given for the experimental method used for determination of the tracer response, including choice of tracer and tracer addition and monitoring. Data analysis techniques were reviewed, and the method of time domain fitting was developed into a computer program, IMPULSE. IMPULSE provided a tool for analysis of residence time data, and removed the constraint of numerical complexity. Using the building blocks of IMPULSE, a realistic flow model can be constructed from tracer data and evaluated. IMPULSE allows a quantitative comparison of models proposed for a process, and provides the parameters of the models. These parameters quantify the non-idealities in a process. A knowledge of the non-idealities provides a basis for decision-making when modifying a process. The results of tracer experiments performed on some water and waste water treatment processes were analysed using IMPULSE. The results showed that collection of good experimental data was critical to the success of the analysis. It is proposed that a guide be produced which draws out the main points raised in the study, including collection of tracer data and use of IMPULSE. The guide should be accessible and easily understandable to the staff managing and operating water and waste water treatment works. / Thesis (M.Sc.Eng.)-University of Natal, Durban, 1995.

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 179-186). / xix, 215 leaves, bound ill. 29 cm

Thesis (M.Eng.) -- University of Western Sydney, 2004. / A thesis submitted in fulfilment of the requirements for the degree of Master of Engineering at the University of Western Sydney. Includes bibliography.

Thesis (M.Eng. (Chemical Engineering)) -- Universiteit van Pretoria, 2007. / Includes bibliographical references.

Thesis (M.Arch.) - Carleton University, 2005. / Includes bibliographical references (p. 91-94). Also available in electronic format on the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 94-98). Also available via the Internet.