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The demand for water supply is increasing rapidly across the world due to the exponential growth of population, swift urbanization, and industrialization. Methods for recovery of reusable water from domestic, industrial and agricultural wastewater should be cost-effective, and environmentally safe for the sustainability of water resources. Domestic wastewater is one of the contaminated water sources which need efficient treatment before discharge into water bodies. The novelty of the present study is to treat domestic rice gruel wastewater by coagulation integrated aerobic membrane bioreactor (AMBR) for the generation of reusable water. A hydrophilized ultrafiltration (HF-UF) spiral wound membrane of 5 kDa molecular weight cut off was used for the treatment of rice gruel wastewater at a feed temperature of 30 °C and 80 °C to study separation performance. Further, a comparison study was carried using various coagulants such as methanol, ethanol, and HCl for integration with HF-UF membrane to determine overall process efficiency at 30 °C. Methanol coagulation + HF-UF membrane based integrated process was able to achieve 93.77%, 95.4%, 91%, and 78.6 %, respectively of total dissolved solids (TDS), turbidity, conductivity, and chemical oxygen demand (COD). Further, this process was integrated with a bioreactor operated under aerobic conditions to improve the process efficiency and purified water quality. From the overall experimental results, the integrated coagulation + AMBR process attained a maximum removal of 93.9, 96, 91, and 94.6 percent of TDS, turbidity, conductivity and COD, correspondingly. Finally, an economic estimation of a 1000 Lh-1 capacity pilot plant is described in detail. The study depicts unique advantages of economy, process safety, small footprint, and eco-friendly for rice gruel wastewater by a combination of chemical coagulation with AMBR.

The need for a more sustainable wastewater treatment is more relevant now due to climate change. Production and reuse of methane from anaerobic treatment is one pathway. However, this is defeated by the presence of dissolved methane in the effluent and would be released to the environment, adding to the greenhouse gas emissions. This review paper provided summary and analysis of studies involved in the production of dissolved methane from AnMBR, focusing with actual methane measurement (gas and dissolved) from AnMBR with different types of wastewater. Then more focused discussion and analysis on the use of membrane-based technology or membrane contactors in the recovery of dissolved methane from AnMBR effluent are included, with its development and energy analysis. The dissolved methane removal and recovery rate of membrane contactors can be as high as 96% and 0.05 mol methane/m2/h, respectively, with very low additional energy requirement of 0.01 kWh/m3 for the recovery. Future perspectives presented focus on the long-term evaluation and modelling of membrane contactors and on the membrane modifications to improve the selectivity of membranes to methane and to limit their fouling and wetting, thus making the technology more economical for resource recovery.

The demand for water supply is expected to be raised significantly in forthcoming decades. Production of reusable water from industrial and domestic wastewater is a feasible, cost effective and significant positive benefit to the environment. In the present study, the domestic rice gruel wastewater (RGW) was treated with aqueous methanol coagulation integrated aerobic membrane bioreactor (AMBR). Initially, the RGW which is at room temperature was treated with spiral wound hydrophilized - ultrafiltration (HF – UF) 5 kDa membrane module to determine the removal efficiency. Furthermore, the RGW was pre-treated with various coagulants such as methanol, ethanol and HCl. The obtained pre-treated RGW was subjected to the HF – UF 5 kDa side stream AMBR for production of reusable water. The experiments were conducted to determine the turbidity, conductivity, total dissolved solids (TDS) and chemical oxygen demand (COD) were found to be 96 %, 91 %, 91 % and 94.6 %. The overall process was feasible, compact, environmental free, cost effective, eco-friendly.

Activated sludge models (ASMs) are often used in the simulation of the wastewater treatment process to evaluate whether the effluent quality parameters of a wastewater treatment plant meet the standards. The premise of successful simulation is to choose appropriate dynamic parameters for the model. A niche based adaptive invasive weed optimization (NAIWO) algorithm is proposed in this paper to find the appropriate kinetic parameters of activated sludge model 1 (ASM1). The niche idea is used to improve the possibility of convergence to the global optimal solution. In addition, the adaptive mechanism and periodic operator are introduced to improve the convergence speed and accuracy of the algorithm. Finally, NAIWO is used to optimize the parameters of ASM1. Comparison with other intelligent algorithms such as invasive weed optimization (IWO), genetic algorithm (GA), and bat algorithm (BA) showed the higher convergence accuracy and faster convergence speed of NAIWO. The results showed that the ASM1 model results agreed with measured data with smaller errors.

Microbial fuel cell (MFC) is an eco-friendly energy source that generates electricity by degrading natural wastes through bacterial activity. The electrolyte that is sandwiched between the ...

Effluent from textile mills is considered one of the most polluted among all industrial effluents because it contains a large amount of toxic dyes that are released during the dyeing proces...

Lipids are biomolecules extracted from plant sources and plant residues and have a beneficial role in various food, nutrition and medical applications. Supercritical carbon-dioxide as an advanced high-pressure technology which increases the productivity and has negligible environmental impact is employed for the selective extraction of polar lipids from the lipid matrix in mango kernel for the first time. The process parameters affecting the extraction such as pressure, temperature and the flow rate of CO

Polyvinylidene fluoride (PVDF) membrane was coated with polyvinyl alcohol (PVA)/titanium dioxide (TiO

Compared with the traditional activated sludge process, a membrane bioreactor (MBR) has many advantages, such as good effluent quality, small floor space, low residual sludge yield and easy automatic control. It has a promising prospect in wastewater treatment and reuse. However, membrane fouling is the biggest obstacle to the wide application of MBR. This paper aims at summarizing the new research progress of membrane fouling mechanism, control, prediction and detection in the MBR systems. Classification, mechanism, influencing factors and control of membrane fouling, membrane life prediction and online monitoring of membrane fouling are discussed. The research trends of relevant research areas in MBR membrane fouling are prospected.

This study investigated the photocatalytic degradation of remazol turquoise blue (RTB) dye using titanium dioxide (TiO

A mathematical model, which was previously developed for submerged aerobic membrane bioreactors, was successfully applied to elucidate the membrane cake-layer fouling mechanisms due to bound extracellular polymeric substances (eEPS) in a submerged anaerobic membrane bioreactor (SAnMBR). This biofouling dynamic model explains the mechanisms such as attachment, consolidation and detachment of eEPS produced in the bioreactor on the membrane surface. The 4th order Runge-Kutta method was used to solve the model equations, and the parameters were estimated from simulated and experimental results. The key design parameters representing the behaviour of cake fouling dynamics were systematically investigated. Organic loading rate (OLR) was considered a controlling factor governing the mixed liquor suspended solids (MLSS), eEPS production, filtration resistance (Rt), and transmembrane pressure (TMP) variations in a SAnMBR. eEPS showed a proportional relation with OLR at subsequent MLSS variations. The consolidation of EPS increased the specific eEPS resistance (αs), influencing the cake resistance (Rc). The propensities of eEPS showed a positive correlation with Rt and TMP. The outcomes of the study also estimated a set of valuable design parameters which would be vital for applying in AnMBRs treating industrial wastewater.

© 2018 Elsevier Ltd Diffusion coefficient of solutes through a porous membrane media is different from diffusion coefficient through a free homogenous media. Porosity, tortuosity and the thickness of the membrane significantly affect the diffusion through a specific thickness of a membrane and therefore it is termed as effective diffusion coefficient (Deff) which is lower than the actual diffusion coefficient, D. The Deff of single or dual solutes through a porous membrane layer are well documented but not for multiple salts. Therefore, in this study, single, dual and multiple salt mixtures were passed through a flat sheet cellulose triacetate Forward Osmosis (FO) membrane to obtain a semi-empirical relationship with the Deff and its water flux. This will allow computing the structural coefficient of FO membranes. Research community have spent tremendous efforts in membrane modification to reduce the structural coefficient to improve FO process efficiency. Our finding suggests that optimising the draw solution chemistry can achieve this goal.

Microfiltration membranes having different blends of graphene-oxide (GO) (0–1 wt%) and Polysulfone (PSf) (15–20 wt%) were prepared using the classical non-solvent induced phase inversion process. The prepared membranes were characterised for their structural morphology, surface properties, mechanical strength, porosity and pure water flux. Based on the initial characterisation results, four membranes (15 wt% PSf, 15 wt% PSf + 0.25 wt% GO, 15 wt% PSf + 1 wt% GO and 20 wt% PSf + 1 wt% GO) were chosen for critical flux study, that was conducted using flux-step method in a lab scale MBR system. In order to study the application potential of GO blended membranes, the critical flux of each membrane was evaluated in two operational modes i.e., continuous and intermittent modes with backwash. The membranes with maximal GO concentration (15 wt% PSf + 1 wt% GO and 20 wt% PSf + 1 wt% GO) showed higher critical flux (16.5, 12.8 L/m2h and 19, 15 L/m2h for continuous and intermittent mode, respectively). It was observed that the operational modes did not have a significant effect on the critical flux of the membranes with low GO concentration (15 wt% PSf and 15 wt% PSf + 0.25 wt% GO), indicating a minimal of 1 wt% GO was required for an observable effect that favoured intermittent mode of operation. Through these results, ideal operating condition was arrived (i.e., flux maintained at 6.4 L/m2h operated under intermittent mode) and the membranes 15 wt% PSf and 15 wt% PSf + 1 wt% GO were studied for their long-term operation. The positive effect of GO on filtration time, cleaning frequency and against fouling was demonstrated through long term TMP profile of the membranes, indicating the suitability of GO blended membrane for real time wastewater treatment.

Performance of two novel designed anaerobic membrane bioreactor (AnMBRs) for wastewater treatment at long hydraulic retention time (HRT, 47 days) and high sludge concentration (22 g·L−1) was investigated. Results showed steady chemical oxygen demand (COD) removal (> 98%) and mean biogas generation of 0.29 LCH4·g−1COD. Average permeates flux of 58.70 L·m−2·h−1 and 54.00 L·m−2·h−1 were achieved for reactors A and B, respectively. On top of reactor configuration, long HRT caused biofilm reduction by heterotrophic bacteria Chloroflexi resulting in high membrane flux. Mean total membrane resistances (2.23 × 109 m−1) and fouling rates (4.00 × 108 m−1·day−1) of both reactors were low suggesting better membrane fouling control ability of both AnMBRs. Effluent quality analysis showed the effluent soluble microbial products (SMP) were dominated by proteins compared to carbohydrates, and specific ultraviolet absorbance (SUVA) analysis revealed effluent from both reactors had low aromaticity with SUVA < 1 (L·mg−1·m−1) except for the first ten days.

Reusing treated effluents in industries is a great option to conserve freshwater resources. For example, car wash centres all over Australia are estimated to use 17.5 billion litres of water and discharge it as wastewater and spend $75 million a year for both purchasing fresh water and for treating and/or discharging the wastewater. Therefore, it is important to develop simple but reliable systems that can help to treat and reuse car wash wastewater. Significant savings could also be associated with the implementation of such systems. This study evaluates the performance of granular and membrane filtration systems with coagulation/flocculation and sedimentation in treating car wash wastewater for the purpose of reuse. Overall, 99.9% of turbidity, 100% of suspended solids and 96% of COD were removed from the car wash wastewater after treating by coagulation, flocculation, sedimentation, sand filtration, ceramic ultrafiltration and reverse osmosis and the treated water meets the standards required for class A recycled water in Australia and standards imposed in Belgium and China. The treated water can be reused. However, optimisation is required to reduce the sludge produced by this system.

Nano and micro plastics (NP/MPs) represent one of the most challenging classes of micro-pollutants, with occurrence across all ecosystems and size distributions ranging from the nanometre to the millimetre scale. These broad composition and size distribution ranges limit the efficiency of detection methods, often inherently focused on a single and narrow class of NP/MPs sizes. In addition to their demonstrated native toxicity, NP/MPs may act as efficient carriers of pollutants and pathogens onto their surface, facilitating the transfer and penetration of other classes of hazardous materials. This comprehensive review presents the key challenges related to soil, air and water NP/MPs: (i) sampling and extraction, (ii) using defined synthetic NP/MPs for spiking environmental samples and for model studies, and (iii) characterisation. A major challenge discussed in this paper relates to the lack of relevant characterisation strategies for the NP/MPs materials, enabling simultaneous identification, quantification and generation of statistical size distributions. This critical discussion ends with a series of well-informed propositions to support the systematic assessment of the impact of NP/MPs materials, spanning from materials science and characterisation, as well as environmental and chemical engineering.

Zeolite-based zirconium functional materials (Ze-Zr) were obtained by the response surface methodology (RSM). The experimental conditions such as zeolite particle size, the concentration of zirconium oxychloride, mass ratio of zeolite and zirconium, processing time and temperature and assimilation temperature were optimized. The central Box–Behnken design (BBD) and mathematical modelling were adopted for optimizing experimental parameters. FT-IR, XRD and SEM were used to analyze the structure and morphology of the obtained Ze-Zr materials. The Ze-Zr materials with highest phosphorus removal rate of 97.08% were prepared under the following conditions: 0.15–0.20 mm of zeolite, 0.04 M zirconium, mass ratio of 0.09 of zeolite and zirconium, processing for 4 h and 100 °C as drying temperature.

The aim of the present work was to experimentally evaluate an alternative advanced wastewater treatment system, which combines the action of photocatalytic oxidation with ceramic membrane filtration. Experiments were carried out using laboratory scale TiO2/UV photocatalytic reactor and tubular ceramic microfiltration (CMF) system to treat the secondary effluent (SE). A 100-nm pore size CMF membrane was investigated in cross flow mode under constant transmembrane pressure of 20 kPa. The results show that specific flux decline of CMF membrane with and without TiO2/UV photocatalytic treatment was 30 and 50%, respectively, after 60 min of filtration. Data evaluation revealed that the adsorption of organic compounds onto the TiO2 particles was dependent on the pH of the suspension and was considerably higher at low pH. The liquid chromatography-organic carbon detector (LC-OCD) technique was used to characterise the dissolved organic matter (DOM) present in the SE and was monitored following photocatalysis and CMF. The results showed that there was no removal of biopolymers and slight removal of humics, building blocks and the other oxidation by-products after TiO2/UV photocatalytic treatment. This result suggested that the various ions present in the SE act as scavengers, which considerably decrease the efficiency of the photocatalytic oxidation reactions. On the other hand, the CMF was effective for removing 50% of biopolymers with no further removal of other organic components after photocatalytic treatment. Thus, the quantity of biopolymers in SE has an apparent correlation with the filterability of water samples in CMF.

An Ametryn (an s-triazine herbicide) fed laboratory-scale membrane bioreactor (MBR) was studied for 214 days under sub-tropical conditions (20–22 °C) for evaluating its treatment/operating performance and to consolidate the previous findings and establish the design parameters. Ten short-term critical flux tests were carried out at different stages of the study and the Critical Flux Values (CFV) varied from 6 to 33 L/m 2 h for the experiments carried out under intermittent suction mode. Two numerical models were used to estimate the “ critical times ”, which is useful to establish the chemical cleaning frequency of membrane modules and to assess the key kinetic parameters required to design a pilot/full scale MBR. The study also confirmed the overall fluctuation of the components of polymeric substances (proteins and carbohydrates of extra-cellular polymeric substances (EPS) and soluble microbial products (SMP)) in the MBR due to the addition of different concentrations of Ametryn (0–4 mg/L).

There has been a considerable expansion in the use of desalination plants for supplying potable water to many communities in the world. However, the production of brine, which is known to be a concentrated solution, is an integral part of the operation of the desalination plant, which faces critical environmental challenges because of its high salinity. Therefore, a cost-effective and environmentally benign brine management system is required prior to its proper disposal. Currently, several disposal options including surface water discharge, deep well injection, and evaporation ponds have been used. However, these processes are unsustainable and their use is limited by a high capital cost and limited applications. Various conventional treatments including physicochemical, oxidation and biological processes with varying extents of organics removal have been reported. Nowadays, membrane-based technologies appear to be cost-effective methods for managing brine concentrate as they can recover valuable resources and produce clean water with high recovery. This paper critically reviews current technologies for concentrate management, including disposal practices and treatment processes. The characteristics of the brine in terms of water quality and its impact on open water bodies are discussed. This paper examines emerging membrane processes such as forward osmosis, membrane distillation, and electrodialysis that show promise for minimizing brine volume, in recovering valuable resources and improvement of water recovery. This paper also discusses the fact that integrated membrane processes are better for brine management for resource recovery together with water purification in wastewater treatment facilities and can achieve a zero liquid discharge.

This paper attempts to prepare high-performance activated carbon (HP-AC) from bamboo charcoal (BC) as raw material using microwave irradiation as heating source and potassium hydroxide as activating agent. The influence of factors, such as activation time (3-15 min), KOH/C ratio (1:1-6:1) and particle size (0.147-2 mm) on its performance (the carbon yield and adsorptive capability) were investigated. The textural porosity and surface chemistry of HP-AC were determined by scanning electron microscope (SEM) analyzer, N 2 adsorption method and Fourier-transform infrared (FT-IR) spectrometer. The adsorptive properties of HP-AC were examined using iodine solution and methylene blue as model dye compound and hydrogen adsorbate. The effect of porosity and surface functionalities on the electrochemical capacitance of HP-AC were measured by cyclic voltammetry measurements. Under the best preparation conditions (activation time of 8 min, KOH/C ratio of 5:1 and particle size of 0.71-1.4 mm), the following results were obtained for the specific surface area, micro surface area, external surface area, total pore volume, iodine adsorption value, methylene blue adsorption value, carbon yield, hydrogen storage capacity and super capacitance value: 2,446 m 2 /g, 901 m 2 /g, 1,545 m 2 /g, 1.48 mL/g, 2,226 mg/g, 47.5 mL/0.1 g, 34.3%, 0.93 wt% (17.3 MPa, 25°C) and 3.63 wt% (1.0 MPa, -196°C), 212 F/g, respectively. The findings revealed the potential of BC as a raw material for the preparation of HP-AC, and to determine its potential applications of HP-AC as hydrogen storage and super-capacitor material.

It is difficult to capture the real-time online measurement data for biochemical oxygen demand (BOD) in wastewater treatment processes. An optimized extreme learning machine (ELM) based on an improved cuckoo search algorithm (ICS) is proposed in this paper for the design of soft BOD measurement model. In ICS-ELM, the input weights matrices of the extreme learning machine (ELM) and the threshold of the hidden layer are encoded as the cuckoo's nest locations. The best input weights matrices and threshold are obtained by using the strong global search ability of improved cuckoo search (ICS) algorithm. The optimal results can be used to improve the precision of forecasting based on less number of neurons of the hidden layer in ELM. Simulation results show that the soft sensor model has good real-time performance, high prediction accuracy and stronger generalization performance for BOD measurement of the effluent quality compared to other modeling methods such as back propagation (BP) network in most cases.

Membrane technology has a wide range of applications in upstream and downstream bioprocessing of industrial products. Due to the increased interest in the development of continuous bioprocessing units, bioreactors coupled to membrane separation processes have been extensively assessed in the last decade, showing incredible potential for its application in food and pharmaceutical industries as well as energy production and environmental remediation. In this chapter, applications of membrane bioreactors (MBRs) in biotechnology processes are reviewed. Moreover, removal of recalcitrant pollutants (e.g., trace organic contaminants) by MBRs is critically analyzed. Bottlenecks affecting the scale-up of MBRs in biotechnology processes are identified and discussed.

With the ever increasing population growth in urban areas, stakeholders have adopted numerous water sensitive urban design (WSUD) measures to enable the recycling and reuse of stormwater for a range of non-potable fit-for-purpose uses. This chapter highlights the most common measures adopted across Australia in the recent past, their benefits and limitations. Findings suggest that the adoption of WSUD measures have provided multiple tangible and intangible benefits from a social, environmental and economic context. For further expansion and adoption of WSUD measures, the multiple benefits need to be communicated and shared with the scientific and the broader community further to create sustainable and water resilient urban areas.

Production of carboxylic acids from anaerobic fermentation has gained increasing attention. However, acidogenic fermentation is still facing challenges such as low yield of carboxylic acids and difficulties in product recovery and purification. The emission of acidogenic off-gas CO2 leads to a reduced carbon recovery (∼70%) and also increases the carbon footprint of the anaerobic treatment process. In this study, a tailored electrodialysis stack was integrated with a fermenter to recover the products and hence to improve quantity and quality of the produced carboxylic acids. Three levels of currents, i.e., 0.4, 1, and 4 A (T1, T2, and T3), were applied during electrodialytic separation of carboxylic acids and 12 cycles of electrodialysis were carried out to evaluate the performance of the integrated system. Results showed that different degrees of carboxylic acids removal led to varied impacts on the yield of carboxylic acids, economic viability, and the instability of microbial community. Compared with the case without coupling electrodialysis process, the carbon conversion rate increased by 28.04% in T3, which was due to the reuse of inorganic carbon introduced by a tailored electrodialysis process. After 12 cycles of fermentation, the percentage of Clostridiales finally increased from 0.11% (inoculum) to 31.15% in T3, which also confirmed the possible autotrophic acidogenesis by using inorganic carbon. This work would provide a promising solution to improve the recovery of carboxylic acids from organic wastes and achieve minimum carbon footprint in the organic waste management process.

Old industrial landfill leachate (OILL) poses a significant challenge to the environment, due to the large volumes of the solid waste directly discharged into landfills which leach out by percolation during rainfall and degradation of organic waste. Various separation processes have been used for the treatment of OILL to reduce environmental pollution. The innovation in the present study is the integration of membrane ultrafiltration (UF) process with chemical coagulation to remove pollutants such as total dissolved solids (TDS), conductivity, turbidity, and color from an OILL. Various coagulants such as ferric chloride (FeCl3), activated carbon (AC) and their combinations with alum ((Al(SO4)3) and lime (Ca(OH)2) were used to optimize pretreatment by coagulation. Experiments were conducted by varying the composition of coagulants and sedimentation time. Reduction in parametric values of TDS from 3200 to 1500 mg L-1, conductivity from 5.00 to 2.34 mS cm−1, turbidity from 226 to 1 FAU, color from 2930 to 10Pt-Co, and pH from 8.23 to 4.86 were achieved by a combination of coagulation by FeCl3 and UF membrane process. Moreover, greater removal of turbidity and color of 98.7% and 99.48%, respectively were observed. Further, the coagulation kinetics were established on the basis of the pH of the supernatant liquid through modeling using SMOLUCHOWSKI equation and observed to follow first-order kinetics. FeCl3 coagulant + UF was found capable of promoting maximum removal of color and turbidity compared to the other combinations. The integrated process exhibits advantages of small footprint of equipment used, economy, environmental safety, low energy consumption, and ease of scale-up for OILL treatment with simultaneous water reclamation of at least 70%.

In this study, thin-film composite (TFC) polyvinylidene fluoride (PVDF) membranes were synthesized by coating with titanium dioxide (TiO2)/polyvinyl alcohol (PVA) solution by a dip coating method and cross-linked with glutaraldehyde. Glutaraldehyde (GA) acted as a cross-linking agent to improve the thermal and chemical stability of the thin film coating. The incorporation of TiO2 in the film enhanced the hydrophilicity of the membrane and the rejection of dyes during filtration. The layer of TiO2 nanoparticles on the PVDF membranes have mitigated the fouling effects compared to the plain PVDF membrane. The photocatalytic performance was studied at different TiO2 loading for the photodegradation of dyes (reactive blue (RB) and methyl orange (MO)). The results indicated that the thin film coating of TiO2/PVA enhanced photocatalytic performance and showed good reusability under UV irradiation. This study showed that nearly 78% MO and 47% RB were removed using the TFC membrane. This work provides a new vision in the fabrication of TFC polymeric membranes as an efficient wastewater treatment tool.

Graphene oxide (GO) based magnetic nano-sorbent was synthesized by assembling the Fe3O4 and GO on the surface of polystyrene (denoted as PS@Fe3O4@GO). The morphology of the nano-sorbent was studied using scanning electron microscopy (SEM), while their individual nano-components were characterized using UV–visible spectroscopy, atomic force microscopy (AFM), zeta potential, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The assembled nano-sorbent was further investigated for Pb (II) ions removal by optimizing the parameters including pH, temperature and contact time. The obtained data was modelled for adsorption kinetics, adsorption isotherms and thermodynamics. Kinetic experiments indicated the Pb (II) adsorption followed first order kinetics. The adsorption equilibrium data fits Langmuir isotherm model well and the adsorption process was found to be spontaneous. The adsorption capacity of the prepared nano-sorbent was estimated to be 73.52 mg g−1, with a maximum removal of 93.78% at pH 6. The nano-sorbent can be regenerated by nitric acid (HNO3) for reuse. FT-IR and X-ray photoelectron spectroscopy (XPS) studies confirmed the interactions between the Pb (II) ions and the nano-sorbent.

In this paper, a photocatalyst POM/TiO2 was prepared using heteropolyacid salt (NH4)4[Mo8O24(C3H2O4)2]·4H2O (denoted as POM) and TiO2 via solid phase combustion method. The structure of POM/TiO2 was characterized by scanning electron microscopy (SEM), X-ray spectrometer (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and the photocatalytic activity was evaluated by degrading toluene under UV light illumination. The results showed that when (i) the mass ratios of POM/TiO2 were 1:0.7, (ii) the calcination temperature was 400 °C, (iii) ecalcination time was 3 h, the degradation ratio for toluene was 67.55% and it was an increment of 36.23% compared with those of TiO2 alone. TiO2/POM exhibited excellent photocatalytic activity.

Fundamental understanding of pH dynamics in forward osmosis (FO) processes is integral for further development of this emerging technology in desalination and wastewater reclamation. In this study, the pH changes during FO membrane filtration were investigated. CaCl2·2H2O was used as the draw stream and NaCl as the feed stream. During the FO process, water would flow from the feed to draw so that the feed stream would become concentrated while the draw stream being diluted. It was found that the pH of the feed stream increased with time. Assuming that the pH or the concentration of hydrogen ions to be constant in the FO system, the pH of the draw stream should decrease. Surprisingly, the pH of the draw stream also increased. To explain this unexpected phenomenon, standard curves for both CaCl2·2H2O and NaCl were constructed. In contrast to conventional belief, the standard curves showed that pH of NaCl increased with the increase in concentration while pH of CaCl2·2H2O decreased with the increase in concentration. As such, the standard curves explain the reason for pH increase in both feed and draw solutions. Furthermore, the curves showed that the pH to be dependent on salt concentration, where charges on ions have the ability to influence the pH of the solution.

Car wash wastewater contains significant concentrations of contaminants such as nutrients, organics, particulate matter, sand, oil, grease, diesel detergents and so on. A range of treatment processes such as a membrane bioreactor (MBR), coagulation and ozonation were investigated to treat car wash wastewater. Ozonation was effective in removing the chemicals and suspended solids; the removal efficiency was greater than the coagulation process. Once the MBR system was acclimatised, 100% of suspended solids, 99.2% of COD, 97.3% of TOC and 41% of ammonia were removed. This study demonstrates that MBR is a potentially promising treatment system for recycling car wash wastewater which could be reused in the same car wash station.

Membrane crystallization is an innovative concept to treat water and recover minerals from concentrates. Thus, it will also be beneficial to the existing mineral extraction industry. This process combines membrane distillation (MD) with crystallization. While MD produces water and concentrates the feed, crystalliser forms crystals from supersaturated minerals in the concentrated feed. This review covers principles of this process, factors affecting membrane crystallization for water treatment, application of membrane crystallization, resource recovery and the fouling of membrane crystallization. Membrane crystallization could recover many minerals including sodium, magnesium, barium, strontium, and lithium. However, fouling is a major challenge for its widespread implementation. Further directions for future research and development of this process are also considered with a view to the sustainable operation of the process.

Membrane bioreactor (MBR) technology has been used widely for various industrial wastewater treatments due to its distinct advantages over conventional bioreactors. Treatment of textile wastewater using MBR has been investigated as a simple, reliable and cost-effective process with a significant removal of contaminants. However, a major drawback in the operation of MBR is membrane fouling, which leads to the decline in permeate flux and therefore requires membrane cleaning. This eventually decreases the lifespan of the membrane. In this paper, the application of aerobic and anaerobic MBR for textile wastewater treatment as well as fouling and control of fouling in MBR processes have been reviewed. It has been found that long sludge retention time increases the degradation of pollutants by allowing slow growing microorganisms to establish but also contributes to membrane fouling. Further research aspects of MBR for textile wastewater treatment are also considered for sustainable operations of the process.

Seawater Reverse Osmosis (SWRO) desalination is being used by several countries to aid the current demand for fresh water, hence numerous large scale and small scale desalination plants have been built during last decade. Despite major advancements in SWRO technology, the desalination industry is still facing significant practical issues. Two of the major issues are (1) generation of higher volumes of pre-treatment sludge, and (2) overall water recovery. This paper proposes a novel hybrid reverse osmosis (RO) – forward osmosis (FO) system to overcome the above two drawbacks. Mass balance calculations based on laboratory experiments have been used to predict increased water recovery and reduced pre-treatment sludge volume arising from large scale (340,000 m3/day of intake) and small scale (15,000 m3/day of intake) hybrid SWRO desalination plants. The percentage reduction of pre-treatment sludge volume, increase in overall RO water recovery, FO membrane area required and dilution in RO reject have been estimated.

This in-situ analysis quantifies hydrogen sulfide gas emission from a simulated sewerage system, with varying slopes between 0.5% and 1.5%, under the dosing of certain mitigating chemicals. A portable H 2 S gas detector (OdaLog) was employed to record the gaseous phase concentration of hydrogen sulfide. The investigation was comprised of three interrelated phases. In the first stage, precision of four prediction models for H 2 S gas emission from a laboratory-synthesized wastewater was assessed. It was found that the model suggested by Lahav fitted the experimental results accurately. Second phase explorations included jar tests to obtain the optimal dosage of four hydrogen sulfide suppressing chemicals, being Mg(OH) 2 , NaOH, Ca(NO 3 ) 2 , and FeCl 2 . In the third stage, the optimal dosage of chemicals was introduced into the experimental sewerage system, with the OdaLog continuously monitoring the H 2 S gas emission. According to a baseline (experiments with no chemical addition), it was found that NaOH and Mg(OH) 2 performed very good in mitigating the release of H 2 S gas, while Ca(NO 3 ) 2 was not effective most probably due to the absence of biological activity. Furthermore, interpretation of OdaLog data through the optimum emission prediction model revealed that higher sewer slope led to more emission.