Thesis (M.Tech.)-Department of Biotechnology, Durban University of Technology, 2006 xvi, 126 leaves / The microbial community present in a laboratory-scale modified Ludzack-Ettinger activated sludge system was investigated using a combination of novel molecular techniques. The parent system was investigated for a duration of one year and samples were taken at regular intervals to determine the profile and structure of the microbial community present within the anoxic and aerobic zones of the MLE system. The combination of molecular techniques included fluorescent in situ hybridisation (FISH) and denaturing gradient gel electrophoresis (DGGE). FISH was performed using oligonucleotide probes, which were complementary to conserved regions of the rRNA for the alpha, beta and gamma subclasses of the gram negative family Proteobacteria as well as a group-specific HGC oligonucleotide probe as a representative of the gram positive actinomycetes branch. The total eubacteria present was determined using the EUB oligonucleotide probes, EUB388, EUB388-II and EUB388-III. The DGGE analysis of PCR-amplified 16S rDNA gene segments was used to examine the microbial community profile in the anoxic and aerobic zones. The profile for each of the zones revealed a number of consistent bands throughout the duration of the laboratory-scale process. However, the profiles obtained suggested that a diverse microbial community existed within the aerobic and anoxic zones. The bands also indicated the presence of dominant and less dominant species of bacteria. Hybridisations obtained from the FISH analyses indicated that the alpha and gamma subclasses were predominant within the anoxic zone and the aerobic zone showed a dominance of the beta subclass of Proteobacteria. The steady state behaviour of the MLE system was confirmed with the results obtained from COD, TKN, nitrates and OUR analytical tests. COD and nitrogen mass balances were conducted to confirm the acceptance of the results obtained for each batch as an indication of the system performance for the MLE model. Nitrogen mass balances indicated an upset in the nitrogen levels for batches two and seven.

Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnology, Durban Institute of Technology, 2005 xiv, 114 leaves : ill. 30 cm / The activated sludge process is the mostl used biological treatment process. Engineers and microbiologists are constantly seeking ways to improve process efficiency, which can be attributed to the increasing demand for fresh water supplies and proper environmental management. Since the inception of the activated sludge process, bulking and foaming have been major problems affecting its efficiency. Filamentous bacteria have been identified as the primary cause of bulking and foaming. Numerous attempts have been made to resolve this problem. Some of these attempts were effective as interim measures but failed as long term control strategies. The identification of filamentous bacteria and the study of their physiology have been hampered by the unreliability of conventional microbiological techniques. This is largely due to their morphological variations and inconsistent characteristics within different environments. To fully understand their role in promoting bulking and foaming, filamentous bacteria need to be characterized on a molecular level. The aim of this study was, therefore, to identify filamentous bacteria in pure culture with the purpose of validating these findings to the physiological traits of the pure cultures when they were isolated. Fourteen different filamentous cultures were used for this study. The cultures were identified using specific oligonucleotide probes via fluorescent in situ hybridisation and nucleotide sequencing. Prior to sequencing, an agarose gel and a denaturing gradient gel Electrophoresis profile were determined for each isolate. The various techniques were optimised specifically for the filamentous isolates. The isolates were identified as Gordonia amarae, Haliscomenobacter hydrossis, Acinetobacter sp./Type 1863, Type 021N, Thiothrix nivea, Sphaerotilus natans and Nocardioform organisms.

Thesis (D.Tech.: Biotechnology)-Dept. of Biotechnology, Durban University of Technology, 2008. xxiv, 322 leaves / Activated sludge models now in use worldwide for the design and operation of treatment systems use hypothetical concentrations of active organisms. In order to validate and calibrate model outputs, concentrations and activities of organisms responsible for nitrification and denitrification need to be reflected by actual measurements. This research has been initiated by the observation of an increasing gap of suitable techniques that exist in the direct measurement and separation of active biomass components, responsible for COD removal and denitrification.

Thesis (MEng (Civil Engineering))--University of Stellenbosch, 1983. / 129 leaves printed on single pages, preliminary pages and numbered pages 1-1 – 12.5. Includes bibliography, list of abbreviations and list of figures. / Digitized at 300 dpi black and white PDF format (OCR), using KODAK i 1220 PLUS scanner. / ENGLISH ABSTRACT: The remedy of a bulking sludge was investigated by the principle of selection of microorganisms. Selection of microorganisms in activated sludge was achieved by putting a selection compartment, with a high substrate concentration, ahead of the main aeration basin. The initial results in the experiments indicated selection of microorganisms and a reduction of SVI, but complete selection of microorganisms could not be obtained. / AFRIKAANSE OPSOMMING: Die herstel van 'n uitdyende slyk is deur die beginsel van selektering van mikroorganismes ondersoek. Selektering van mikroorganismes in geaktiveerde slyk is toegepas deur n seleksie kompartement met 'n hoë substraatkonsentrasie, voor die groot belugtingsbak te plaas. Die aanvanklike resultate wat verkry is, het selektering van mikroorganismes en 'n verlaging in die SVI getoon, maar volledige selektering van mikroorganismes kon nie verkry word nie.

<p>För att simulera aktivslamprocessen på ett reningsverk krävs en dynamisk modell som realistiskt beskriver processen. 1987 kom IWA, International Water Association med ASM1, Activated Sludge model no. 1 som fortfarande är den mest använda modellen för att beskriva denna process. I detta examensarbete har ASM1 används för att beskriva aktivslamprocessen på Henriksdals reningsverk i Stockholm. Arbetet har utförts som en del i ett europeiskt projekt, HIPCON (Holistic Integrated Process CONtrol) på IVL, Svenska Miljöinstitutet AB.</p><p>Arbetet har gått ut på att ta fram en modell som realistiskt beskriver aktivslamprocessen och eftersedimenteringen. För att göra detta har en referensmodell i MATLAB/Simulink använts som grund och byggts om för att likna processen vid Henriksdal. Denna modell i Simulink använder ASM1 för att beskriva aktivslamprocessen. Eftersedimenteringen modelleras med en massbalansmodell där sedimenteringshastigheten beskrivs av en dubbelexponentiell sedimenteringsfunktion. Både ASM1 och sedimenteringsfunktionen använder en mängd olika parametrar för att beskriva processerna och dessa måste kalibreras fram för den process som skall modelleras. Aktivslamprocessen är en biologisk process som beror på en mängd yttre och inre faktorer och är unik för varje reningsverk. Därför finns det inte något enkelt sätt att kalibrera en modell på och information för det enskilda reningsverket i fråga måste tas fram. I detta arbete har två mätkampanjer utförts på Henriksdal för att få mätserier till kalibrering och validering samt information om avloppsvattnets sammansättning. Litteraturstudier har också genomförts för att få information om vilka parametervärden som är av störst intresse för modellen samt i vilket område varje parameter kan förväntas finnas.</p><p>Arbetet har sedan gått ut på att efter riktlinjer för kalibrering funna i litteraturen ta fram en modell som så realistiskt som möjligt beskriver processen på Henriksdal. Först genomfördes en kalibrering med medelvärden för att hitta jämviktstillstånd och därmed en stabil modell på länge sikt. Utifrån den modellen utfördes sedan en dynamisk kalibrering för att få en modell som beskriver även kortsiktiga och snabba förändringar. Till sist utfördes en validering för att kontrollera om modellen fungerar även för en dataserie som ej använts vid kalibrering. Den framtagna modellen fungerade mycket bra för att modellera medelvärden på lång sikt. För snabba förändringar verkade modellen ligga fel i tiden och troligtvis var den reella uppehållstiden kortare än den teoretiska och bidrar till sämre modellanpassning.</p> / <p>To simulate the activated sludge process at a wastewater treatment plant a dynamic model that describes the process is needed. In 1987 IWA, International Water Association presented ASM1, Activated Sludge Model No.1 which still is the most widely used model for this process. In this thesis the ASM1 has been used to describe the activated sludge process. The work is a part of a European project, HIPCON (Holistic Integrated Process CONtrol) at IVL, Swedish Environmental Research Institute.</p><p>The main objective of the work was to calibrate a model that realistically describes the activated sludge process and secondary sedimentation at Henriksdal wastewater treatment plant in Stockholm. A benchmark model in MATLAB/Simulink was used as a base and rebuilt and extended to fit the process of Henriksdal. In the model ASM1 is used to describe the activated sludge process. The settler is modelled with a mass balance model where the settling velocity is described by a double exponential function. The parameters used in both models have to be calibrated to fit the wastewater treatment plant. To find information about Henriksdal two measuring campaigns were performed to provide data for calibration and validation and to gather information about the composition of the incoming wastewater. From this data a model was developed and calibrated for the process at Henriksdal. After calibration the obtained model worked very well for modelling average values but did not adjust quite as well to fast dynamic changes.</p>

<p>This thesis work was made for Södra Cell Mörrums bruk in Blekinge. The purpose of the work was to develop a computer model in the simulation program Extend for the removal and balance of organic oxygen consuming substances, measured as COD (Chemical Oxygen Demand), in the new biological treatment plant in the mill. The plant produces two different pulp products, TCF- (Totally Chlorine Free) pulp and ECF- (Elementary Chlorine Free) pulp, for sale. The different bleaching procedures affect the characteristic of the wastewater and thus the effectiveness of the biological treatment plant.</p><p>In the model that was developed the COD in the wastewater was divided into five different COD-fractions: soluble easily degradable (SS), soluble hardly degradable (SR), soluble inert (SI), particulate inert (XI) and particulate biomass (XB). To create the model FlowMac™ was used as a base. FlowMac™ is a library module in Extend adapted for pulp and paper mills. Some of the blocks only needed a slight modification while others, for example the sedimentation basin and the bioblocks, had to be done from scratch. The calibration of the model was made from data from a period of eleven weeks and a validation was made from data that differed as much as possible from the calibration data. Then the model was used to find out in what way an increase in production to 480 000 annual tons should affect the discharge of organic oxygen consumption substances.</p><p>Results from the model indicates that the goals for the total COD-discharge will be hard to achieve with an increase in production to 480 000 annual tons. Despite the fact that production of TCF-pulp generates more COD than ECF-production the total discharge of COD is lower at TCF-production. The reason is that easier degradable COD is generated in TCF-bleaching. One of the major problems is that the torrent of water that is bypassed the biological treatment plant contains a large amount of COD and the efficiency of the treatment plant must be very high if the goals for the total COD-discharge shouldn’t be exceeded.</p> / <p>Det här examensarbetet gjordes för Södra Cell på Mörrums Bruk i Blekinge. Arbetet bestod i att göra en modell i simuleringsprogrammet Extend över nedbrytningen och massbalansen av organiska syreförbrukande ämnen, mätt som COD (Chemical Oxygen Demand), i den nybyggda biologiska reningsanläggningen på bruket. Mörrums bruk är en sulfatmassafabrik som producerar både TCF- (Totally Chlorine Free) och ECF- (Elementary Chlorine Free) massa för avsalu. De olika blekningsmetoderna påverkar sammansättningen på avloppsvattnet och därmed också den biologiska reningsanläggningens reduktion av COD.</p><p>I modellen som utvecklades delades inkommande COD i obehandlat vatten upp i fem olika COD-fraktioner: löst lättnedbrytbart (SS), löst svårnedbrytbart (SR), löst inert (SI), partikulärt inert (XI) och partikulärt nedbrytbart COD i form av biomassa (XB). För att bygga modellen användes FlowMac™ som utgångspunkt. FlowMac™ är en biblioteksmodul i Extend avpassad för pappersbruk. En del block behövde bara modifieras medan andra block, t.ex. sedimenteringen och bioblocken, fick byggas till. Modellen kalibrerades med medelvärden från en elvaveckorsperiod och en validering gjordes med data från några veckor med mer extrema värden på inkommande vatten. Med modellen gjordes en simulering för att undersöka vad en produktionsökning till 480 000 årston skulle innebära med avseende på utsläppen av organiska syreförbrukande ämnen.</p><p>Resultat från modellen tyder på att det vid en ökning av produktionen till 480 000 årston blir svårt att nå de uppställda totala utsläppsmålen för COD. Vid produktion av TCF-massa bildas mer COD men utsläppsmängderna är lägre än vid ECF-produktion. Anledningen är att den COD som bildas ut vid TCF-blekning innehåller en större mängd lättnedbrytbart COD. En bidragande orsak till att det blir svårt att hålla utsläppsmålen för COD är att de flöden som leds förbi reningsanläggningen innehåller mycket COD vilket gör att verkningsgraden över reningsanläggningen måste vara hög för att klara målen för totala COD-utsläppet.</p>

Wastewater activated sludge is produced during the biological treatment of wastewater. After treating the sewage, the sludge is allowed to settle. Part of the settled material is returned to the treatment process as return activated sludge (RAS) and the excess is removed as waste activated sludge (WAS). The handling and disposal of the sludge are energy and capital-intensive treatments, with a significant environmental impact. This work studies the possibility to utilize RAS (an example of wastewater sludge) as a source of surface active agents. The results indicate that higly surface active materials can be extracted from RAS, and that the RAS extract has potential applications as a detergent and wood adhesive. The results also suggest that recovering a suite of products from RAS, a biological heterogenous source, can be technically feasible. An effective alkaline treatment was developed (at pH>12) that can extract up to 75% of the sludge’s organic matter, a yield higher than previously reported. Increasing the extraction pH increased the extract surface activity, which is linked to increasing the amount of higher molecular weight molecules and the presence of phospholipids. Increasing the extraction pH beyond 11 was also related to extensive cell lysis, increasing significantly the amount of recovered material and the surface activity of the extract. The alkaline extract has properties comparable to commercial detergents. Without further purification, the extract has a low surface tension (37 mN/m on average) and performs similarly to synthetic detergents. Further assessment of the RAS extract (insensitivity to pH, surface tension, interfacial tension) suggests that it may be suitable for commercial applications. The RAS extract can also be formulated into wood adhesives using glutaraldehyde as a crosslinker. The extract fraction with 10-50 kDa constituents at pH 9 achieves high adhesive shear strengths (4.5 MPa on average, at 30% relative humidity and 25°C) with 40% of wood failure. The adhesive strength of RAS-based adhesives is strongly correlated to its protein content.

Managed aquifer recharge (MAR) consists of artificially replenishing groundwater to facilitate reuse and/or the associated environmental benefits. Meanwhile, soil aquifer treatment (SAT) is a process of geo-purification designed and operated to improve the quality of the infiltrating water and is thus a type of MAR. SAT consists of a basin operating under rotation of drying and wetting periods. Often, SAT involves water of impaired quality applied onto soil and consequently it implies various risks of health, geochemical and physical nature with difficult or irreversible remediation. To study the effect of pre-treatment on SAT a pilot plant including conventional activated sludge (CAS), a membrane bioreactor (MBR), tertiary and secondary vertical flow reed beds (VFRB) and SAT soil columns. The sludge retention time (SRT) in the CAS and MBR processes was changed every 6 months to look at the impact of SRT on SAT. Each unit and treatment train effluent was characterised to determine the impact of effluent quality on SAT performance. This study showed that tertiary VFRB, especially when fed with MBR effluent, was the best option for SAT and irrigation reuse as it provided the best compliance with reuse standards and the best fertilisation potential. However, long-term clogging occurred in SAT after tertiary VFRB, suggesting the need for a longer resting period or shorter wetting period. This study also highlighted the importance of total suspended solids (TSS) content for SAT removal mechanisms and infiltration rate. In particular, SAT fed with high TSS content effluent was susceptible to temperature variation. Hence the duration of wetting and flooding periods should be adapted according to the season. Further, variation in SRT only indirectly affected pollutants removal by the system including CAS treatment set up at 6 d SRT where the N compounds balance was favourable to an autotrophic N removal.

L’objectif de ce travail est de caractériser l’effet de l’érythromycine sur l’activité bactérienne et l’inhibition de l’épuration dans les réacteurs de traitement des eaux usées urbaines. L’étude a montré l’importance du temps d’exposition à l’érythromycine. L’inhibition de la nitrification et de l’épuration de la DCO a été mesurée sur une période de 4 h pour des concentrations supérieures à 1 mg/L d’érythromycine alors que l’inhibition de l’épuration pour une concentration d’érythromycine de 4 µg/L a été mesurée suite à 20 h d’exposition. L’origine de la liqueur mixte est également déterminante : l’érythromycine a inhibé la nitrification avec les boues de Nancy mais n’a pas inhibé la nitrification avec les boues et Épinal. Par contre, l’inhibition de l’épuration de la DCO a été mesurée pour les deux boues. Des analyses microscopiques ont montré qu’en présence d’érythromycine les flocs bactériens se fractionnaient suite aux lyses bactériennes. La microscopie en épifluorescence et la microscopie confocale combinées à des marqueurs de viabilité fluorescents ont permis de déterminer les vitesses de mortalité bactérienne. Ces études ont mis en évidence un temps de latence qui précède la mortalité des bactéries. Ce temps de latence pourrait être lié aux mécanismes d’adsorption de l’antibiotique et de diffusion dans les flocs, ainsi qu’à la vitesse biologique de mortalité. Enfin, un marquage simultané Gram et viabilité (microscopie confocale 3D au cours du temps) a montré que l’érythromycine pourrait modifier la composition bactérienne des boues en sélectionnant les bactéries les moins sensibles / This study examines the effect of erythromycin on activated sludge bacteria and the inhibition of the pollution removal in batch reactors treating urban wastewater. Results showed the importance of exposure time to erythromycin. Inhibition of nitrification and COD removal was measured during a 4 h period for erythromytcin concentrations higher than 1 mg/L. A 4 µg/L erythromycin concentration inhibited COD removal during a 20 h exposure time. The effect of erythromycin on nitrification was variable depending on the sludge origin. Erythromycin inhibited the specific nitrification rate with sludge from Nancy WWTP, but increased the nitrification rate at the other facility (Epinal WWTP). The cell lysis resulted in destruction of activated sludge flocs. Microscopic techniques (epifluorescence and confocal laser scanning microscopy (CLSM)), combined with a fluorescent viability indicator, allowed us to study erythromycin time-kill activity.Viability staining results showed a latency time before the lower antibiotic concentrations began to kill bacteria. This latency time could be related to antibiotic adsorption and diffusion into activated sludge flocs as well as the rate of bateria death. The effect of erythromycin according to the bacterial Gram type was investigated with 3-dimensional Confocal Laser Scanning Microscopy (CLSM) time-lapse imaging combined with a Gram and Viability staining. Gram+ bacteria had a higher mortality rate than the Gram- bacteria. This result suggests that antibiotic in wastewater could change the activated sludge bacteria composition according to their Gram type by selecting bacteria the less sensitive to the antibiotics

<p>The antimicrobial properties of silver have been taken advantage of by societies for thousands of years. Its use has come back in favor in the form of silver nanoparticles, which are highly efficacious antimicrobial agents. Silver nanoparticles are incorporated into a myriad of products specifically designed for clinical use, but also for general use by consumers. Silver nanoparticles can be found in textiles such as clothing and stuffed toys, and in home appliances including washing machines and curling irons. A large number of products specifically marketed for use by children are also available to consumers, including pacifiers, sippy cups, and even breast milk storage bags. The hazards and toxicities associated with silver nanoparticles are not well understood, however modes of toxicity have been reported for ionic silver. It is assumed that the main mechanism of toxicity of silver nanoparticles relates to the release of ionic silver, however studies have indicated an additional nano-effect, likely due to nanoparticle size, differential coatings, and means of sustained dosing of ionic silver. However we are sure that these silver nanoparticles will accumulate in the waste stream, likely arriving during different stages of a product’s lifespan. A main sink of these nanoparticles travelling through both natural and engineered environments is wastewater treatment plants. As a society we rely on the biological removal of nutrients, which takes place primarily in the activated sludge of secondary treatment. Studies have already indicated possible, temporary decreases in removal efficiencies as well as changes in microbial communities, including losses of diversity, following exposure to silver nanoparticles. Therefore, it is of paramount importance to examine the effects of both silver nanoparticles and ionic silver on the community and function of wastewater bacteria. </p><p> Sequencing batch reactors were operated to mimic wastewater treatment. They were fed synthetic wastewater and after reaching acclimation, were dosed over time with varying concentrations of both ionic and nanosilver. Cell samples were collected periodically to assess the presence and identity of cultivable silver resistant bacteria and to map the microbial community changes taking place under different treatments using Next Generation Sequencing. Isolates were tested for the presence of known silver resistance (sil) genes as were activated sludge samples from a collection of domestic wastewater treatment plants, by designing TaqMan probe assays and performing quantitative PCR. The silver resistant isolates were also used to test the growth implications, as well as sil gene expression changes, following treatment with ionic silver and a variety of silver nanoparticles with various coatings, all at multiple concentrations. This was accomplished by performing multiple batch experiments and then using the TaqMan assays and reverse transcription-quantitative PCR.</p><p>Overall, microbial community changes were observed in the sequencing batch reactors, and there were differences noted based on treatment, including ionic silver versus nanosilver and between the two silver nanoparticle coatings. Most notably, the possibility of nitrification in wastewater treatment being particularly susceptible was strongly indicated. Individual wastewater bacteria isolates all contained sil genes, as did the majority of the wastewater treatment plant activated sludge, however the levels of actual sil gene expression were inconsistent. This particular finding supports a current body of work indicating that there are alternate modes of bacterial silver resistance in play that we are just becoming aware of.</p> / Dissertation