Cleaning Cycle Research Articles

Enhanced anti-wetting and anti-fouling properties of composite PFPE/PVDF membrane in vacuum membrane distillation

Composite hydrophobic PFPE/PVDF membranes were prepared by coating and UV-curing for vacuum membrane distillation (VMD). The water contact angle of PFPE/PVDF membrane reached 162.6°, while the decrease in pore size in comparison to the original membrane was insignificant. The effects of organic and inorganic foulants (including humic acid, sodium silicate and calcium carbonate) on membrane performance were investigated. As for this PFPE coating layer, it had an active mitigation effect on the scaling behavior and almost no membrane wetting occurred. In particular, the organic migration across the membrane was completely prevented. Then the membrane cleaning process was conducted to prove the stability under long-term operation of composite membranes when deionized (DI) water was used as cleaning agent after repeated cycles of VMD treatment of 2 M NaCl feed solutions containing 200 mg/L humic acid (HA). The results of a 30-h test indicate that the salt rejection was kept at a high level, exceeding 99.99% and the recovery of MD flux was around 90% of the initial flux after the second cleaning cycle. The promising anti-fouling and anti-wetting performance of the composite PFPE/PVDF membranes provides a high potential for further development of these membranes for membrane distillation and membrane crystallization applications.

A framework of optimum cleaning schedule and its financial impact in a large-scale PV solar plant: a case study in Senegal

The performance of large-scale PV solar plant installed in sub-Saharan regions is affected by the deposition of dust on the surface of the PV modules. Frequent cleaning of the PV modules increases the profitability of PV solar plants. The objective of this study is to determine the optimal cleaning cycle of a PV solar plant subjected to a wind loaded with sand and dust. This study took place in a PV solar plant installed in Senegal. The measurement data are analysed for a period of two years and used to extract soiling rate. Optimization was done based on the total cost caused by dust on the PV solar plant to minimize the number of days between cleaning events. The results showed that the soiling rate between June and May is 0.34%/day, while a rate of 0.33%/day was recorded in October. The highest soiling rates of 0.42%/day and 0.49%/day were recorded in December and between February and March, respectively. The optimal cleaning cycle for the PV solar plant is 14 days. The total cost of cleaning is reduced by 31% using this optimal cleaning cycle proposed.

Study of clogging on pervious concrete applied on light traffic and pedestrian pavement

ABSTRACT Clogging is an issue related to pervious concrete pavements because sediments accumulate in the concrete voids and reduce its hydraulic conductivity. This study investigates the influence of the sediment typology and material maintenance on its permeability in order to correlate clogging evolution and the hydraulic performance of the material. In the experimental program, pervious concretes were designed with different percentages of fine aggregate, and the samples produced were submitted to permeability tests after sediment deposition and aspiration cleaning cycles. The results indicated that larger particles (sand) caused the loss of permeability by sealing the upper layer of the samples, while fine sediments (clay) clog the lower layers. Maintenance efficiency was demonstrated by the total recovery of permeability for sand clogging and by 96.85% for clay sedimentation. These results prove that, despite affecting the hydraulic performance of the permeable concrete, clogging is recoverable by means of periodic pavement maintenance/cleaning.

Monte Carlo Study of Online Cleaning Cycles of Hydrogenerator Heat Exchangers

Related to an innovative cleaning device for cleaning hydrogenerator heat exchangers that does not require the interruption of generation (turning off the turbines), this article discusses two alternative schemes to estimate the minimum number of cleaning cycles required to ensure that all tubes of the heat exchanger will be visited at least once by the cleaning artifacts used by the conceived online cleaning system. The technique makes use of abrasive sponge balls transported by the cold working fluid of the exchanger to remove scale that accumulates inside the exchanger tubes during its operation. The main purpose of this study is to guide the hydrogenerator field operator in setting up the automation system of the exchanger cleaning system. In a first attempt, a negative binomial probability distribution function was investigated to estimate the number of tries needed to obtain a number of success events, with equal probability of success, after running a number of Bernoulli's experiments, where the last is considered the success case. Getting closer to the physical reality of the problem studied, a Monte Carlo method simulation, making use of a high number of repetitions (10 x 106), appeared to be a consistent mathematical formulation to anticipate the smallest number of cleaning cycles meeting the posed assumption.

Novel strategy for membrane biofouling control in MBR with nano-MnO2 modified PVDF membrane by in-situ ozonation

In this study, ozonation catalyst nano-MnO2 blended polyvinylidene fluoride (PVDF) membrane was fabricated via phase inversion method and applied to membrane bioreactors (MBR), and then coupled with in-situ ozonation to study the anti-biofouling performance and reveal its mechanism. Results showed that, compared with pristine PVDF membrane (MBR_M0), 0.75 wt% and 1.00 wt% nano-MnO2 modified PVDF membrane (MBR_M0.75 and MBR_M1.00) could mitigate the membrane biofouling rate. Meanwhile MBR_M1.00 coupled with in-situ ozonation could increase the membrane cleaning cycle to 1.5 and 2.7 times, compared with MBR_M0 and MBR_M0.75 without in-situ ozonation. The possible mechanisms included that the nano-MnO2 modification coupled with in-situ ozonation directly removed the biofouling on the membrane surface, improved the hydrophilicity of the membrane surface and enhanced the chemical oxidation and biodegradation of membrane biofouling contaminants in the sludge mixture. The results of this work provide a new strategy for the control of membrane biofouling in MBR to treat industrial wastewater.

Process analytical technology in continuous processing: Model-based real time control of pH between capture chromatography and viral inactivation for monoclonal antibody production

A real time mechanistic model-based control strategy is demonstrated for in-line pH adjustment post-capture chromatography and prior to viral inactivation for continuous processing of monoclonal antibodies. At this point in the process, tight control of pH is essential, as pH fluctuations above 3.5 can result in incomplete viral inactivation, while fluctuations below 3.5 can lead to significant aggregate formation. The present approach predicts the pH profile during the transition phase between chromatography wash and elution steps by modelling the process stream at the column outlet as a mixture of two independent buffer systems. Control of pH in this transition phase is a critical consideration in capture chromatography as a significant amount of mAb material is eluted at this time. The model inputs are buffer concentrations, flow rates, and theoretical pKa values, along with cleaning step conductivity profiles which are readily available from a typical process chromatography equipment. The utilization of the most recent cleaning cycle data as an input to the model allows sensitive calibration to the individual process at hand on a column-to-column basis. The model is able to accurately predict the pH profile throughout the elution, as well as calculate the flow rate of the acid (titrant) required at each time point to maintain the pH consistently at 3.5±0.2. The strategy is demonstrated for various buffers, columns, operating conditions, and process deviations in a three-column continuous process, and is a useful and simple approach for achieving robust control of pH at this critical point in the continuous train.

Pilot scale test of wet dust removal by high gravity intensification technology in fertilizer plant

Industrial dust can cause serious harm to the environment and human body. High gravity wet dust removal is a new type of high-efficiency dust removal technology, with the advantages of high dust removal efficiency, low economic cost, convenient operation and maintenance. In this work, a cross-flow rotating packed bed was used as the wet dust removal equipment, and a pilot scale dust removal experiment platform was built at the production site of the enterprise. The dust removal effect of high gravity wet dust removal technology on granulation waste gas in actual production was also studied. The second compound fertilizer plant of TianJi Group emitted dust-containing exhaust gas with a dust content of about 2500 mg/m3 during the production process. Different key parameters including high gravity factor, liquid flow rate and liquid circulation time were investigated on dust removal efficiency and fractional efficiency, and the mechanism of high gravity wet dust removal was analyzed. The obtained results suggested that under the conditions of gas flow rate of 400 m3/h, liquid flow rate of 0.5 m3/h and high gravity factor of 205.61, the dust removal rate was as high as 99.88% with an outlet concentration of less than 10 mg/Nm3. Under three hours of clean water absorption cycle, the dust concentration after purification could still be reduced to less than 10 mg/Nm3, and the dust removal efficiency could reach more than 99%. The relationship between the fractional efficiency of the cross-flow rotating packed bed and the dust particle size was nonlinearly fitted, which showed a good fit. High gravity wet dust removal technology increased the inertial force of particles in the gas through rotation, while atomizing the liquid into a micro liquid. The scales of the two were matched, and the inertial collision was effectively enhanced to improve the dust capture effect. Therefore, high gravity wet dust removal technology can effectively control industrial dust emissions and has a strong potential for industrial applications.

Experimental investigation on filtration characteristic with different filter material of bag dust collector for dust removal

ABSTRACT In order to solve the problems of insufficient filtration performance of bag dust collector in coal mine and improper selection of filter materials, the performance parameters of seven kinds of filter materials were compared and analyzed. The results showed that with the increase of filtration time, the resistance of different filter materials showed an upward trend, the resistance of ordinary filter material increased rapidly, while the resistance of membrane filter material increased more gently. The time required for ordinary filter material to reach the cleaning cycle is relatively short, the cleaning cycle of polyester filter material is 80s, and the amount of dust accumulated on the surface of membrane filter material is always in a rising state. When the dust particle size is between 6.5 μm and 23 μm, the dust removal efficiency of PTFE filter material increases with the increase of filtering wind speed; The field practice shows that after the LFD-45 horizontal film-coated flat bag precipitator with pre-installed PTFE filter material is installed on the tail guide trough of 106belt conveyor, the dust reduction rates of total dust concentration and respirable dust concentration are 98.57% and 98.95% respectively.

Periodic chemical cleaning with urea: disintegration of biofilms and reduction of key biofilm-forming bacteria from reverse osmosis membranes

Biofouling is one of the major factors causing decline in membrane performance in reverse osmosis (RO) plants, and perhaps the biggest hurdle of membrane technology. Chemical cleaning is periodically carried out at RO membrane installations aiming to restore membrane performance. Typical cleaning agents used in the water treatment industry include sodium hydroxide (NaOH) and hydrochloric acid (HCl) in sequence. Rapid biofilm regrowth and related membrane performance decline after conventional chemical cleaning is a routinely observed phenomenon due to the inefficient removal of biomass from membrane modules. Since extracellular polymeric substances (EPS) make up the strongest and predominant structural framework of biofilms, disintegration of the EPS matrix should be the main target for enhanced biomass removal. Previously, we demonstrated at lab-scale the use of concentrated urea as a chemical cleaning agent for RO membrane systems. The protein denaturation property of urea was exploited to solubilize the proteinaceous foulants, weakening the EPS layer, resulting in enhanced biomass solubilization and removal from RO membrane systems. In this work, we investigated the impact of repeated chemical cleaning cycles with urea/HCl as well as NaOH/HCl on biomass removal and the potential adaptation of the biofilm microbial community. Chemical cleaning with urea/HCl was consistently more effective than NaOH/HCl cleaning over 6 cleaning and regrowth cycles. At the end of the 6 cleaning cycles, the percent reduction was 35% and 41% in feed channel pressure drop, 50% and 70% in total organic carbon, 30% and 40% in EPS proteins, and 40% and 66% in the peak intensities of protein-like matter, after NaOH/HCl cleaning and Urea/HCl cleaning, respectively. 16S ribosomal RNA (rRNA) gene sequencing of the biofilm microbial community revealed that urea cleaning does not select for key biofouling families such as Sphingomonadaceae and Xanthomonadaceae that are known to survive conventional chemical cleaning and produce adhesive EPS. This study reaffirmed that urea possesses all the desirable properties of a chemical cleaning agent, i.e., it dissolves the existing fouling layer, delays fresh fouling accumulation by inhibiting the production of a more viscous EPS, does not cause damage to the membranes, is chemically stable, and environmentally friendly as it can be recycled for cleaning.

Experimental Study on the Effect of Dust Deposition on a Car Park Photovoltaic System with Different Cleaning Cycles

For a decade, investments in solar photovoltaic (PV) systems have been increasing exponentially in the Middle East. Broadly speaking, these investments have been facing tremendous challenges due to the harsh weather in this particular part of the world. Dust accumulation is one the challenges that negatively affects the performance of solar PV systems. The overall goal of this paper is to thoroughly investigate the effect of dust accumulation on the energy yield of car park PV systems. With this aim in mind, the paper presents scientific values for further research and opens the horizon for attracting further investments in solar PV systems. This study is based on a real PV system in the Sultanate of Oman and considers different cleaning cycles for 16 months (from 29 July 2018 to 10 November 2019). Furthermore, four different PV groups were assessed, and the system was monitored under different cleaning frequencies. In general, it was found that dust accumulation has a significant impact; under 29-day, 32-day, 72-day, and 98-day cleaning cycles, the average percentages of energy loss due to soiling were 9.5%, 18.2%, 31.13%, and 45.6%, respectively. In addition, the dust effect has a seasonal variation. The study revealed that dust accumulation has a more negative impact during summer than during winter. During summer, the energy losses due to soiling were 8.7% higher than those during winter. The difference was attributed to different environmental conditions, with high humidity and low wind speed being the main factors that worsen the impact of dust during summer. Based on the findings of this research, a monthly cleaning program is highly recommended in the city of Muscat.

Evaluation and Control of Liquation Cracking Susceptibility for CM247LC Superalloy Weld Heat-Affected Zone via Visualization-Based Varestraint Test

The metallurgical aspects of weld cracking in Ni-based superalloys remain relatively unexplored in existing research. The present study performed comprehensive metallurgical and manufactural investigations into the weldability of an Ni-based superalloy, CM247LC, from the viewpoint of the liquation cracking behavior and its susceptibility. Metallurgical solutions to suppress the liquation-cracking susceptibility were derived via the visualization-based Varestraint test, and the possibility of liquation crack-free welding was explored by employing pre-weld heat treatments and laser beam welding. The alloy that was subjected to aging treatment exhibited the lowest liquation-cracking susceptibility (liquation cracking temperature range: 66 K), while the as-cast alloy specimen exhibited the highest liquation-cracking susceptibility (liquation cracking temperature range: 620 K). The metallurgical mechanisms of the liquation cracking susceptibility of as-cast CM247LC weld were elucidated via microstructural analyses and thermodynamic calculations. The suppressed liquation cracking susceptibility of the aged CM247LC can be attributed to the MC-type carbide fraction and homogenized matrix phase, as compared with those of as-cast CM247LC. The aged CM247LC specimen was subjected to gas tungsten arc welding to validate its minimal liquation-cracking susceptibility. The results confirmed the suppression of liquation cracking, due to the low susceptibility of the specimen. However, crackfree welds could not be obtained. Finally, metallurgically sound welds without liquation cracks were successfully obtained via laser beam welding. The outcomes of the present study will facilitate the generation of electric power from fossil fuels via a clean and efficient gas turbine-based power generation cycle.

Controlling cross‐contamination by food allergens

Controlling cross‐contamination by food allergens

Excellent performance of anaerobic membrane bioreactor in treatment of distillery wastewater at pilot scale

A pilot-scale anaerobic membrane bioreactor (AnMBR) was designed and optimized for the treatment of real distillery wastewater. A low hydraulic retention time of 3.5 days was reached after only 3 weeks. The AnMBR could treat up to 3.97 gCOD/L/day with high biogas production at 1.36 NLbiogas/Lbioreactor/day. The performances of an AnMBR and an anaerobic packed-bed bioreactor for treating the same wastewater were compared. The AnMBR had a shorter start-up period (21 days), a higher COD removal efficiency (96.9 %), and higher stability and methane production (0.26 LCH4/gCODinput), indicating the interest of investigating AnMBR industrialization. The membrane performance was also studied, demonstrating a long cleaning cycle interval of at least 44 days. The transmembrane pressure and Food-to-Microorganism ratio were defined to minimize membrane fouling without affecting the anaerobic digestion performance.

Durability of Shield Effectiveness of Copper-Coated Interlining Fabrics

The protective shield effectiveness (SE) of copper-coated polyamide and polyester interlining fabrics at frequen¬cies of 1.8 GHz, 2.1 GHz and 2.4 GHz are presented in this study. These fabrics were treated through 10 cycles of dry and wet cleaning. After the characterization of shield effectiveness, fabrics were stored in a dark and dry place. On the basis of the SE values at all measured frequencies, it was confirmed that the copper-coated protective polyester fabric had better SE durability under storage conditions than the copper-coated polyamide fabric. Accordingly, the copper-coated polyester interlining fabric is more suitable for integration into functional clothing due to its use cycle.

Global analysis of optimal cleaning cycle and profit of soiling affected solar panels

The photovoltaics (PV) industry is poised to capture most of the energy sector within the next few decades. As the installed PV capacity increases, even the smallest improvements on the system and operations of the solar farms can accumulate to a significant gain in revenue. One such scope is efficient mitigation of dust accumulation on panels or soiling. While installed capacities are two of the highest in Asia and around US deserts, these locations are also dust prone. The Middle East and North Africa (MENA) regions having good insolation are also highly potential candidates for PV farms with the added complexity of soiling losses. Therefore, while soiling may not be an issue in many locations over the globe, it is in fact relevant to the majority of the PV installation sites. The analysis of the effects of soiling losses on energy yield and economics are of great importance for these locations. In this work, we have extended the empirical soiling model found in the literature to include the effects of temporal variation on soiling and insolation. Our study on variation in revenue with unoptimized cleaning intervals estimates the soiling loss, which can particularly interest PV farms with accessibility issues such as agrophotovoltaic systems. We analyze the optimal cleaning cycle and corresponding normalized revenue (cash inflow normalized to the rated clean farm revenue). A numerical model is used to explain the effects under seasonal and sudden (e.g., sand storm or rain) variations in soiling and insolation. Our closed-form analytical expressions can predict the cleaning cycle and normalized revenue within 0.1% of the numerical results by using the soiling and insolation data averaged over the seasons. Finally, we discuss these results in a global scenario using our estimated world-map for soiling rates. This predicts the worldwide revenue loss under location-specific optimal cleaning cycles, assuming one of the lowest cleaning costs seen globally. In Asia and MENA regions, for example, median revenue loss due to soiling is 2.5% even after optimal cleaning every 5–6 days. This loss is 1.5% in the US for 12 days of cleaning interval. Considering region-specific cleaning costs, the revenue loss of optimally cleaned PV farm is 2%–5% for Asia, MENA, North America, and Europe.

Optimal Cleaning Cycle Scheduling under Uncertain Conditions: A Flexibility Analysis on Heat Exchanger Fouling

Fouling is a substantial economic, energy, and safety issue for all the process industry applications, heat transfer units in particular. Although this phenomenon can be mitigated, it cannot be avoided and proper cleaning cycle scheduling is the best way to deal with it. After thorough literature research about the most reliable fouling model description, cleaning procedures have been optimized by minimizing the Time Average Losses (TAL) under nominal operating conditions according to the well-established procedure. For this purpose, different cleaning actions, namely chemical and mechanical, have been accounted for. However, this procedure is strictly related to nominal operating conditions therefore perturbations, when present, could considerably compromise the process profitability due to unexpected shutdown or extraordinary maintenance operations. After a preliminary sensitivity analysis, the uncertain variables and the corresponding disturbance likelihood were estimated. Hence, cleaning cycles were rescheduled on the basis of a stochastic flexibility index for different probability distributions to show how the uncertainty characterization affects the optimal time and economic losses. A decisional algorithm was finally conceived in order to assess the best number of chemical cleaning cycles included in a cleaning supercycle. In conclusion, this study highlights how optimal scheduling is affected by external perturbations and provides an important tool to the decision-maker in order to make a more conscious design choice based on a robust multi-criteria optimization.

Sewage concentration via a graphene oxide modified thin-film nanocomposite forward osmosis membrane: Enhanced performance and mitigated fouling

• The GO modified TFN-FO membrane shows improved filtration performance. • The GO modified TFN-FO membrane shows an enhanced antifouling property. • The GO modified FO membrane has high and stable sewage concentration performance. • High water flux recovery rates can be achieved by simple membrane cleaning. Upstream intensification of wastewater pre-treatment could improve the efficiency of the biological wastewater treatment process by separating and concentrating the organic matter. Forward osmosis (FO) technology is a potential upstream intensification strategy for sewage concentration. Herein, a high-performance graphene oxide (GO) modified TFN-FO membrane was fabricated and evaluated. The GO modified TFN-FO membrane showed 41% enhancement in water flux without weakening the selectivity property, due to the improved membrane hydrophilicity, thinner polyamide layer and facilitated water transportation by GO. The enhanced filtration performance and antifouling property of the TFN-FO membrane were confirmed by using simulative foulant solution and raw sewage as feed solutions. Moreover, a 41 h semi-continuous filtration experiment was conducted for sewage concentration using real raw sewage as the feed solution. Results indicated that the TFN-FO membrane achieved 4.6 times sewage concentration with high rejection of ammonia, nitrogen and organics. In addition, with a simple in-line water cleaning-in-place (CIP) process, most of the pollutants could be washed off from the surface of the TFN-FO membrane in 15 min and ~ 90% water flux could be recovered after each cleaning cycle. This work demonstrates the potential application of TFN-FO membranes for sewage wastewater concentration.

Analysis of microstructural properties of ultrafiltration cake layer during its early stage formation and growth

Understanding the development of microstructure of cake layer during filtration can help establish effective operating conditions and membrane cleaning cycles. In this work, dynamic behavior of cake layers formed during early stage of ultrafiltration (UF) of colloids was analyzed in terms of cake porosity, fractal structure and evolution of fouling mechanisms. Experimental data on membrane fouling by SiO2 colloids under different conditions were recorded to study the effect of pH (1.0–8.9), salinity (0–3.5 %wt. NaCl) and nanoparticle concentration (30–1000 ppm). The results show time dependent behavior of cake porosity with a steady state value lower at lower pH and at higher salinity of the continuous phase. Multiple fouling mechanisms were identified to occur sequentially with cake filtration as the dominant mechanism. High fractal dimension (2.45–2.94) was obtained in all conditions tested. Fractal dimension of a growing cake is shown to undergo a sharp transition to a higher value, pointing to cake restructuring during filtration.

Research on the experiment of the enhancement removal of fine sand by hydrocyclone in sewage treatment plant.

The content of fine sand (< 200 μm) in primary sludge is relatively high in Chongqing sewage treatment plant owing to the part of rainwater will be mixed with sand and discharged into the municipal pipe network. Due to the insufficient separation of the sand, different obstacles to subsequent treatment processes may increase equipment wear, reduce effective volume of the tank, or shorten the cleaning cycle. There is a common use of grit chamber for the separation. Nevertheless, the use of hydrocyclone shows an outstanding performance in cost effectiveness and ease operation. The primary sludge in a sewage plant in Chongqing was monitored, and the average concentration of total suspend solids (TSS), total sand content, and volatile suspended solid (VSS) were 40.25 g/L, 17.51 g/L, and 13.41 g/L, respectively. The size of sand in the sludge was small, and the sand below 30 μm accounted for about 70% of the total sand. It formed flocs with organic matter and was removed in subsequent process units. While the size between 30-200 μm, called fine sand, was the main separation object, accounted for about 28.5%. According to XRF and XRD analysis, the sludge composition was mainly composed of quartz (SiO2), plagioclase (Na(AlSi3O8)), and calcite (CaCO3), which were similar to the main mineral composition of surface sediments and mountain rocks in the main urban area of Chongqing. A single-factor experiment on two types (FX100 and FX50) of hydrocylones was conducted to determine their abilities concerning the separation of fine sand and enrichment of organic matters from primary sludge. FX100 and FX50 showed best performance in the case of P = 0.17 Mpa, underflow diameter (Du) = 18 mm and P = 0.20 Mpa, Du = 6 mm, respectively. The removal efficiency of fine sand by hydrocyclone FX50 was 71.39%. While, it had poor performance on organic matter enrichment and the removal efficiency of which was 17.38%. By contrast, the removal rate by FX100 reached 61.89% for fine sand and only 6.89% for organic matters detached. The superimposition effect did not appear in the serial experiments on hydrocylone FX100 and FX50, but the power is 3.5 times of that of single-stage hydrocylone FX100. Comprehensive consideration of the processing capacity per unit time and operating power, the hydrocylone FX100 was more suitable for actual operation.

Achieving stable operation and shortcut nitrogen removal in a long-term operated aerobic forward osmosis membrane bioreactor (FOMBR) for treating municipal wastewater

Forward osmosis membrane bioreactor (FOMBR) is an integrated physical-biological treatment process that has received increased awareness in treating municipal wastewater for its potential to produce high effluent quality coupled with its low propensity for fouling formation. However, reverse salt diffusion (RSD) is a major issue and so far limited studies have reported long-term FOMBR operation under the elevated salinity conditions induced by RSD. This study investigated the performance of a FOMBR in treating municipal wastewater under a controlled saline environment (6–8 g L−1 NaCl) using two separate sodium chloride draw solution (NaCl DS) concentrations (35 and 70 g L−1) over 243 days. At 35 g L−1 NaCl DS, the water flux performance dropped from 6.75 L m−2 h−1 (LMH) to 2.07 LMH after 72 days of operation in the first experimental stage, when no cleaning procedure was implemented. In the subsequent stage, the DS concentration was increased to 70 g L−1 and a weekly physical cleaning regime introduced. Under stable operation, the water flux performance recovery was 67% after 21 cycles of physical cleaning. For the first time in FOMBR studies, a shortcut nitrogen removal via the nitrite pathway was also achieved under the elevated salinity conditions. At the end of operation (day 243), the ammonia-oxidising bacteria (Nitrosomonas sp.) was the only nitrifier species in the system and no nitrite oxidising bacteria was detected. The above study proves that a FOMBR system is a feasible process for treating municipal wastewater.