A schematic diagram of the experimental set up used is shown in Figure 3. Each submerged anaerobic membrane bioreactor (SAMBR) has a working volume of 3 litres, and is made of acrylic panels. Each reactor contains a standing baffle designed to direct the fluid to the upcomer and downcomer regimes. The reactors were maintained at 35 ± 1°C, and the biomass was continuously mixed using headspace biogas that was pumped (Charles Austen Pumps, Model B100SEC) through a stainless steel tube diffuser to generate coarse bubbles. The bubbles push the sludge flow upward between the membrane module and the reactor wall in the upper section. A flask (500 mL) was placed before the biogas pump in order to collect any sludge going to the gas line due to excessive foaming or excess of liquid in the reactor so that the biogas pump was protected against any liquid that could harm the mechanism. The sparging rate was controlled by a gas flowmeter (2 - 20 LPM, ColeParmer, USA) to minimise membrane fouling. A data logging system (USB-1408FS, Measurement computing) was used to monitor transmembrane pressure (PMP1400, 1 bar A, Druck), and permeate flow rates (13 – 100 mL/min, Flow Sensor Ryton Sensor, McMillan). The membrane module (Kubota) had 0.1 m 2 of total surface
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Figure 1 shows a diagram of the experimental set-up used for this study. The SAMBR was made from polymethyl methacrylate (Plexiglas ® ) and had a working volume of 3 L. A microfiltration flatsheet membrane (size: 222mm × 315mm × 6mm, Chlorinated Polyethylene) from Kubota with a surface area of 0.116 m 2 and a maximum pore size of 0.4 and average of 0.2 μm was used. The flux of the membrane was set at 15 litres per square meter per hour (LMH) for most conditions (HRT 12, 8, 6, 4 and 2 h) using a membrane flux pump to keep it below the critical flux (24 LMH), although at an HRT of 1 h it had to be set to 27.4 LMH to allow for this short HRT. The HRT was set using another pump on the effluent line after the flux pump. The sludge inoculum was obtained from an anaerobic digester in a WWTP in Singapore. The mixed liquor volatile suspended solids (MLVSS) in the reactor were 6,000 mg/L at the start of the experiment at each HRT, and the SAMBR was operated at a 200 days SRT. The pH in the system was maintained in the range of 6.8 and 7.2 using 1M NaHCO 3 . Oxidation-
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Overall, it was demonstrated that the treatment of high-strength OFMSW leachate in the SAMBR was feasible at 5 days HRT, a MLTSS around 2-3 g/L, 10 LPM and under these conditions COD removal greater than 90% and fluxes of 3-7 LMH are possible at TMP levels lower than 200 mbar for 4 months without chemical cleaning of the membrane. Conventional anaerobic reactors such as continuously stirred tank reactors (CSTR), would typically require 30 days or longer to treat such complex high-strength wastewater which means that a considerably larger reactor (6x) would be required. The SAMBR can achieve good COD removal at relatively low HRTs due to the membrane which retains the slow growing methanogens and uncouples the HRT from the SRT. For large scale application where space is a constraint, the anaerobic
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A marked difference in colour was observed among the various MW fractions, with the low MW fraction (< 1 kDa) being the least coloured, indicating that the light brown-yellow colour of the SAMBR permeate was due to compounds larger than 1 kDa which are difficult to degrade due to their humic nature. In this study it was found that the various fractions MW<1 kDa, 1<MW<10 kDa, 10<MW<50 kDa and MW>50 kDa contributed to 24.6 %, 20.4 %, 32 % and 23 % of the total effluent COD (≈1.2 g/L), respectively, therefore showing that all MW fractions contribute to relatively similar COD content in the range 20-32 %. Furthermore, the use of a 1 kDa membrane to treat the SAMBR effluent resulted in 75 % COD removal (= 100 % - 24.6 %), but the 1 kDa permeate still contained about 290 mg/L of COD. Wang et al.  also concluded that large MW ROS were the major COD components of aged raw landfill leachate, and that ROS with MWs larger than 1 kDa were the major colour contributors.
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This study investigated the evolution of archaeal and bacterial populations of two Submerged Anaerobic Membrane Bioreactors (SAMBRs) operating at a mean Solids Residence Time (SRT) of 30 (SAMBR30) and 300 days (SAMBR300) at mesophilic and psychrophilic temperatures. The SAMBRs were fed with leachate produced in a hydrolytic reactor (HR) treating the Organic Fraction of Municipal Solid Waste (OFMSW). The archaeal fingerprint using Denaturing Gradient Gel Electrophoresis (DGGE) showed different populations in the first and second stage of the two- stage anaerobic process. A build up of Volatile Fatty acids (VFAs) was observed at 20ºC in SAMBR30, while in SAMBR300 the VFAs only built up at 10ºC. The dominant bacterial species in the HR belonged to Prevotella and Thauera, while the dominant ones in SAMBR300 belonged to Sphingobacteriales, Anaerovorax, Spirochaetaceae, Hydrogenophaga, Ralstonia, Prevotella and Smithella. The low bacterial diversity in SAMBR30 compared to SAMBR300 resulted in a persistently high Soluble Chemical Oxygen Demand (SCOD) (>2 g/L) in the bulk reactor due to an insufficient residence time for bacteria to carry out the degradation of recalcitrant COD found in the leachate.
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Recently, there is an increasing interest in the applica- tion of AnMBRs to municipal wastewater treatment [14-16]. Table 2 summarised some of the reported re- sults on the applications of AnMBR in municipal waste- water treatment. Many studies showed that AnMBR can achieve efficient COD removal at temperature ranging from 20˚C to 30˚C in the treatment of municipal waste- water with a HRT from 24 to 6 hours tested. Most of studies showed that a long-term sustainable flux around 5 to 10 LMH was achievable for the municipal wastewater treatment AnMBRs. Lin et al.  conducted a feasibil- ity evaluation of submerged anaerobic membrane biore- actor for municipal secondary wastewater treatment. A cost analysis based on their lab-scale test showed that the operational cost of an AnMBR could be only 1/3 of the aerobic treatment process and the energy generated from Table 1. Treatment performances and process conditions of AnMBR used in high strength wastewater treatment.
An increase in aromatic compounds was however seen in the MBR effluent (32%), compared to the anoxic (13%) and aerobic stage (12%). This finding is consistent with Liang et al. (2007) who found that the percentage of aromatic compounds in the total SMPs increased after passing through the membrane, and aromatic SMPs seemed much less prone to accumulate in the MBR. This increase in the percentage of aromatics in the MBR effluents from an anoxic-aerobic MBR fed on simple and biodegradable substrates was interesting; aromatic compounds are generally more recalcitrant, and may not be easily degradable during biological treatment, thereby causing the residual COD (Aquino and Stuckey, 2004). It was also observed that certain aromatic compounds with high concentrations, such as Phenol, 2,4-bis(1,1-dimethylethyl)- (17.32 µg/L), exhibited consistently recalcitrance along biological wastewater treatment process; while Phenol, 2,4-bis(1,1-dimethylethyl)- phthalic acid, 4,4- dimethylpent-2-yl octyl ester (17.32 37.39 µg/L) was only present in the MBR effluent, implying that some compounds possibly transformed into more aromatic structures during biological treatment.
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process treatment of figure. In starting, aerated lagoon was using for wastewater treatment where natural or artificial aeration was used for treatment process. After aerated lagoon, Activated sludge process (ASP) was introduced where primarily treated water was collected in primary settling tank (PST) for proper settling of sludge, supernatant water from PST was further treated biologically in aeration tank (AT) followed by secondary settling tank (SST) and sludge from primary and secondary treatment was collected in Sludge digester (SD), outlet gas from the top of sludge digester was collecting in Gas collecting unit (GCU) and anaerobically digested sludge from the bottom of sludge digester was col- lecting in sludge dewatering unit (SDU). Modification in attached growth system introduced moving bed bio reactor (MBBR) where PST and aeration unit was replaced with MBBR tank, reduced the landscape requirement. Meanwhile, for improvement in effluent quality, research was done on coupling of tertiary treatment with membrane unit which further improved and modified into membrane bioreactor (MBR), Where Anoxic tank (AnT) for denitrification fol- lowed by aerobic tank(AT) for aerobic oxidization of organic waste was also provided but energy cost was again very high for aeration requirement that in- fluenced the anaerobically treatment coupled with membrane unit, which is AnMBR. In anaerobic membrane bioreactor (AnMBR), air requirement for ae- ration tank and additional sludge treatment cost was reduced due to anaerobic process, provided high quality effluent due to coupling with membrane unit.
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Despite the excellent oil separation efficiency of UF membranes, there are several persistent problems that ravage this system from gaining complete reliance to substitute conventional treatment methods, particularly in dealing with those recalcitrant and non-biodegradable contaminants. The potential advantages of SMPR has been utilized to further improve the limitation of UF membrane, however, an in- depth understanding of the theory behind the common reactor operational parameters and their interactions is inadequate and presents a difficult task for maximizing the treatment performance. Other technical challenges are also required to be considered such as possible deterioration of the polymeric membrane material when membrane is directly exposed to UV light for a long period of time during treatment process. This is because the immobilized photocatalysts (in membrane matrix) might absorb UV light energy, causing membrane ageing and further altering its surface morphology and separation performance.
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The tethered type SFT has a higher buoyancy than its own weight. This was accomplished by removing the ballast concrete from the structure. It is very important that no pressure will occur in the tethers, because this would mean that the tunnel would sink. The literature suggests that the use of inclined tethers would give the most preferable result, since this would allow the cables to absorb the loads in the y-direction (Yan, Zhang, & Yu, 2016)(Lin, Mengjun, Guangdi, & Peng, 2016). Therefore the first reference design was designed with inclined tethers in the y-direction. After simulating the forces on the structure it was clear that there was not enough resistance in the x-direction, which made the structure fail. To solve this, the tethers were also inclined in the x-direction which solved the problem. To limit the amount of foundations used, two tethers were connected to one foundation. The reference design can be found in Figure 26 and a more detailed view in chapter 10.1.5 Tethered type of submerged floating tunnel design.
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In a submerged membrane bioreactor, the contribution of aeration plays three roles: (i) supply oxygen to the microorganisms essential for the life and the oxidation of pollutants, (ii) stir the reactor by keeping the particulate matter in suspension (ie the micro-organisms) while ensuring a perfect mixture with the substances to be oxidized and especially (iii) generate turbulence in the vicinity of the membrane in order to reduce the deposition (clogging of the membranes) which is formed during the convective movement related to filtration. Low aeration, or a discontinuous aeration mode are therefore unfavorable to the mixture (settling and / or creation of dead zones) or cause an accelerated clogging of the membranes due to an almost frontal filtration mode [1, 2]. Membrane Bioreactors thus have energy consumption over conventional activated sludge processes due to membrane air averaging around 42% of requirements [3,1,4,5]. The energy costs of typical membrane bioreactor stations in municipal
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With the increasing energy prices and the drive to reduce CO2 emissions, universities and industries are challenged to find new technologies in order to reduce energy consumption, to meet legal requirements on emissions, and for cost reduction and increased quality. Slaughterhouse wastewater causes serious environmental pollution if directly discharged to the land due to its high chemical oxygen demand (COD), Total suspended solids (TSS) and biochemical oxygen demand (BOD). The conventional methods used for slaughterhouse wastewater treatment have both economic and environmental disadvantages. The current study, ultrasonic membrane anaerobic system (UMAS) was used as a high separation, an alternative and cost effective method for treating slaughterhouse wastewater (to avoid membrane fouling).
CONCLUSION. This research work investigated the performance of cassava starch as a proton exchange membrane in a mediator-less microbial fuel cell, MFC, with (aerated cathode and anaerobic anode (pH of 7.2) using swine house effluent as the substrate (fuel). The modification processes of the starch showed significant improvement in the overall performance of the cell with respect to power generation. Even though the maximum power density of 1068.54mW/m 2 generated in the experiment was less than the maximum value achieved previously as recorded in literature, 3600mW/m 2 , from a MFC involving a mediator, the process involved low cost materials with uncoated electrodes assembled in an environmentally safe manner. Furthermore, the operation of the cell involved power generation along side effluent water treatment. Hence, the feasibility of successful operation of MFC using cassava starch (low relative cost) PEM is an attractive one as such would significantly increase the commercial application potential of MFCs.
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were prepared as described above except a lipid concentration of 20 mg/mL was used. Lipid vesicles, octylglucoside (OG), and CymA were mixed by inversion to ﬁ nal concentrations of 16.4 mg/mL lipid, 45 mM OG, and 0.16 or 0.32 mg/mL CymA (i.e., 1 or 2% (w/w) CymA to lipid). QCM-D experiments were performed with 2% (w/w) CymA, while the electrochemistry was done with 1% (w/w). After 15 min incubation on ice, the lipid/protein mixture was rapidly diluted 200-fold with bu ﬀ er, precooled to 4 ° C, and centrifuged at 142 000g for 1 h to pellet the proteoliposomes. The proteoliposomes were resuspended in the same volume of fresh cold bu ﬀ er and centrifuged Figure 1. (A) Schematic of the inner membrane respiratory chain of
Although we failed to identify any other putative ABC- importer components among the fungal transcripts, i.e. the membrane-embedded and cytoplasmic nucleotide binding domains, it is possible that these remain to be identified in the genomes. Alternatively, the sequence similarity to other transporters may be so low that our stringent 70% criterion fails to identify the other ABC transporter components. In any case, the isolated SBP proteins are not likely to function as transmembrane car- riers on their own; however, it is possible that some of these have functions that we cannot easily discern from primary sequence alone. It is tempting to speculate as to their function in the fungi: do these SBP proteins com- municate with fungal transporters, or do they act as sugar sequesters that grasp onto the sugars that the extracellu- lar cellulolytic machinery produces? This could conceiv- ably increase the local sugar concentration around the fungus and lead to increased sugar uptake. Further, SBP proteins in prokaryotes are known to communicate with chemotaxis proteins, and it is possible that the gut fun- gal SBPs play a role in directing the fungal zoospores to nutrient sources by a yet unknown mechanism .
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dark at 30°C with shaking at 200 rpm for 16 h, harvested by filtration, and ground in liquid nitrogen. The plasma membrane fraction was isolated, and protein concentrations were determined as described above. To solubilize membrane- associated proteins, samples containing 2 mg of total protein were adjusted to 360 l with the extraction buffer (see above). Subsequently, 40 l of 5% Triton X-100 was added, and the solution was incubated on ice for 15 min. The mixtures were then centrifuged (21,000 ⫻ g for 15 min at 4°C) to remove insoluble material. The supernatant was diluted with an equal volume of 2 ⫻ coimmuno- precipitation buffer (20 mM Tris-Cl [pH 7.5], 300 mM NaCl), and 80 l of anti-FLAG M2-agarose slurry (Sigma, St. Louis, Mo.) was added. The suspen- sion was incubated at 4°C on a rotating shaker for 3 h. Afterwards, the agarose beads were collected by centrifugation (1,000 ⫻ g for 1 min at 4°C) and washed twice with ice-cold 1⫻ Tris-buffered saline. An aliquot (50 l) of 2⫻ sample buffer (25 mM Tris-HCl [pH 6.8], 4% SDS, 20% [vol/vol] glycerol, 0.004% bromphenol blue) was added to the agarose beads, and the mixture was incu- bated at 95°C for 3 min. The samples were then centrifuged (21,000 ⫻ g for 30 s at room temperature). Aliquots of supernatant (40 l) were then resolved using a 10 (GNB-1 detection) or 15% (GNG-1 detection) SDS-PAGE gel, and the TABLE 2. Oligonucleotides used in this study
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normally continuous and high rates of ATP production. Under these conditions, anaerobic generation of ATP is insufficient to supply the demands of the ATP-dependent transporters, resulting in a dissipation of ionic gradients across the cell membrane. This hypoxia-induced membrane failure, as ions drift towards their electrochemical equilibrium, eventually leads to catastrophic cell swelling and death. In contrast, ectothermic facultative anaerobes maintain pre-anoxic ionic gradients (Sick et al., 1982) at the same time as having a lowered rate of ATP turnover (Perez-Pinzon et al., 1992b). Protein synthesis and degradation are generally considered to account for between 60 and 70 % of the ATP production expected from the oxygen consumption of normoxic non- neuronal tissues (Hochachka et al., 1996). However, when hypoxia-tolerant cells (e.g. turtle hepatocytes) are exposed to anoxia, the ATP demand of protein turnover can drop to less than 10 % of the total ATP production (Buck and Hochachka, 1993). At such times, the ATP concentrations of the cells remain constant or may even rise (Donohoe and Boutilier, 1998; Donohoe et al., 1998; Kelly and Storey, 1988), while total normoxic ATP turnover rates decrease by approximately 90 % (Buck and Hochachka, 1993); all this occurs while the resting potential of the membrane is maintained in both neurones and hepatocytes (Doll et al., 1991; Perez-Pinzon et al., 1992a).
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A further characterisation of the microbial culture by a molecular mechanism, such as PCR or FISH analysis, would have given additional conformation of the presence of an Anammox culture in addition to the morphological characteristics and nitrogen utilisation pattern. While such techniques were not utilised in this work, they are currently being developed for future studies. MEMBRANE PERFORMANCES This project revealed that PVDF membranes performed better than PTFE membranes in Anammox SBMRs, with or without backwashing (Table 2). Hydrophobicity of the membrane surfaces could have played a significant role in the membrane fouling resistance, with PVDF being a hydrophilic membrane and PTFE being hydrophobic. Other studies in general anaerobic SMBRs have presented similar conclusions (Feng et al., 2009; Meng et al., 2008).
duction medium was adjusted to the initial pH of 6 using 1 M NaOH or 1 N HCl and sterilized (121 °C for 15 min). Culture medium was inoculated using 1 % of inoculum and the anaerobic condition was given using nitrogen to replace the oxygen. The flasks were incubated at 30 °C for the fermentation period of 48 h. Samples were withdrawn at 4 h interval after the first 12 h of fermentation when tannase activity started. The cells produced were counted using a Neubauer chamber. Then the cells were separated from the medium by centrifugation at 10,000 rpm for 15 min. The clarified supernatant was used for the anal- ysis of tannase activity, gallic acid synthesis and tannic acid degradation.
This study determined the effect of temperature on the performance of the Submerged Membrane Activated Sludge Reactor on treating synthetic wastewater. In this study, different range of temperature will be used in order to determine the effectiveness of this aerobic reactor. Temperature factors are important in affecting the process performance of the aerobic reactor and have to be considered. This is important to ensure that the effluent that will produce from treatment are followed the allowable standard required.
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