Membrane Technology For Treatment Research Articles

Application of Membrane Separation Technology in Electroplating Wastewater Treatment and Resource Recovery: A Review

The rapid development of industry has led to the generation of a large amount of electroplating wastewater. The direct discharge of untreated electroplating wastewater may lead to the formation of toxic metal-organic complexes, which is a challenging problem for human health and the living environment of organisms. Due to the high solubility of heavy metals in aquatic environments and their easy absorption by organisms, effective treatment of electroplating wastewater is of great significance. The ultimate goal of electroplating wastewater treatment should be to recover metals and water from electroplating wastewater. In indoor experiments, pilot tests, and industrial applications of electroplating wastewater treatment, membrane treatment technology commonly used in wastewater terminal treatment has attracted great attention. Membrane treatment technology seems to be the most promising method for removing heavy metals and organic pollutants from electroplating wastewater. This article reviews the membrane treatment technologies for electroplating wastewater, introduces the advantages and disadvantages of various membranes in the treatment of electroplating wastewater, the removal efficiency of pollutant types, and their comparison. The focus is on the treatment effects of nano-filtration membrane, ultra-filtration membrane, micro-filtration membrane, reverse osmosis membrane, ceramic membrane, biofilm, etc., on electroplating wastewater. Compared with a single treatment method, the combination of different processes shows higher efficiency in removing various pollutants.

Study on Conventional Drinking Water Treatment for Removing Emerging Contaminants: A Literature Review

Emerging contaminants (ECs) are substances that can be synthetic or natural, or even microorganisms that are usually not monitored in the environment and could be harmful to the environment and human health. These chemicals can include pharmaceuticals, such as ibuprofen and acetaminophen, and industrial chemicals, e.g., perfluorooctanoic acid (PFOA). Common conventional drinking water treatment plants (CDWTP) are not designed to remove emerging contaminants, so these compounds can enter the water system and affect the drinking water treatment process. This study aims to focus on the performance of CDWTP in removing ibuprofen, acetaminophen, and PFOA parameters, as well as determine suitable water treatment units to eliminate these parameters from the system. An extensive literature review was conducted and further analysed using descriptive and qualitative analysis to understand the unit performance in removing emerging contaminants, followed by the simple simulation to determine the types of advanced drinking water treatment facilities that perform better in eliminating ECs. The results show that CDWTP could reduce ibuprofen concentration in water with 40%, 20%, and 36% efficiency through coagulation-flocculation, sand filtration, and disinfection, respectively. Acetaminophen removal is up to 67%, 51%, and 66.45% during coagulation-flocculation, sand filtration, and disinfection, respectively. However, PFOA removal is only up to 5%, 7%, and 2% during coagulation-flocculation, sand filtration, and disinfection, respectively. Membrane treatment technology with reverse osmosis could remove ibuprofen, acetaminophen, and PFOA compounds more effectively with removal efficiencies of 99.99%, 96%, and 100%, respectively.

Groundwater remediation by in-situ membrane ozonation: Removal of aliphatic 1,4-dioxane and monocyclic aromatic hydrocarbons

Groundwater contamination by widespread and persistent organic compounds requires extensive treatment efforts, for example by in-situ chemical oxidation (ISCO). In this study, we investigated ozone mass transfer and removal mechanisms of ozone-resistant monocyclic aromatic and non-aromatic compounds in a novel in-situ treatment method using ozone-permeable membranes as reactive barrier. Initial batch experiments confirmed fast depletion of ozone in presence of sub-stoichiometric benzoic acid (BA), in contrast to the non-aromatic 1,4-dioxane (DIOX), where ozone depleted much slower. Simulated in-situ membrane ozonation treatment of contaminated groundwater led to lower removal of 5 mg L−1 BA (52.7%) compared to DIOX (60.6%). Inhibited removal of BA compared to additional batch experiments could be explained by quick depletion of ozone by reactive intermediates on the membrane surface. Surprisingly, reactive porous media did not lead to substantial changes of in-situ DIOX oxidation, although a stronger impact of the media on DIOX oxidation was hypothesized. Furthermore, experimental ozone mass transfer coefficients were determined (3.94∙10−7 – 3.12∙10−6 m s−1) and compared to modeled values for different membrane types (polydimethylsiloxane and polytetrafluoroethylene). Finally, a mathematical model based on mass transfer data was developed to support upscaling efforts. We concluded that contaminant properties are crucial for the feasibility assessment of in-situ ozone membrane treatment technology.

Pilot evaluation of the potential log removal credit using chemical markers for reverse osmosis and nanofiltration

Reverse osmosis (RO) and nanofiltration (NF) are widely applied membrane treatment technologies due to their ability to effectively remove particulates, dissolved compounds, bacteria, and viruses. However, in potable reuse applications, RO is given minimal log removal value (LRV) credit of 1–2 for pathogens due to the inability to demonstrate higher LRV performance daily. Therefore, systematic single-element membrane pilot tests (3 different RO and 1 NF membranes) were performed to assess the potential LRVs (> 4) for three chemical markers (i.e., sulfate, sucralose, and uranine) that could potentially enable membrane-based potable reuse systems to achieve higher credit. Lead- and tail-element tests, as well as new and chlorine-oxidized membranes, were tested to assess the effect of membrane location and damage on the marker LRVs. Undamaged and damaged membranes demonstrated LRVs of >5 for MS2 bacteriophage with no statistically significant differences observed for any of the 4 membranes tested regardless of membrane placement (i.e., lead vs. tail) or condition (i.e., new vs. oxidized). Statistical analysis by optimal cluster assignments for each membrane indicated there were little differences in effective LRVs between the three chemical markers. Though the LRVs could not achieve >4, likely due to diffusion limitations, they were > 2 for the three chemical markers that ranged from 2.7 to 3.6 across non-damaged lead- and tail-element tests for all three RO membranes. Uranine, while achieving LRVs of 2.9–3.6 for RO and 2.2–2.3 for NF for non-damaged lead- and tail-element tests, was deemed less preferable due to its high dose requirement and difficult chemical handling. Sulfate and sucralose proved to be effective as well but preferable with non-damaged, lead- and tail-element test LRVs of 2.7–3.5 for RO and 1.4–2.3 for NF. Damaged-membrane testing demonstrated the three conservative chemical markers were sensitive to the chlorine-oxidized membrane compromise, more so for RO than NF, before any virus breakthrough occurred.

Occurrence and Removal of Pharmaceutical Contaminants in Urine: A Review

With the development of world economies and the continuous improvement of living standards, pharmaceutical and personal care products (PPCPs) have attracted significant attention because of their widespread detection in wastewater and the natural environment. Their biological toxicity, environmental persistence, and other hazardous characteristics might pose a threat to the ecological environment and human health. How to treat source-separated urine as a valuable recyclable resource has become a novel challenge. In this review, we briefly described the sources of pharmaceuticals, explored the various metabolic pathways of pharmaceuticals, and concluded that urinary excretion is the primary metabolic pathway of pharmaceuticals. Next, the current status of pharmaceutical contamination in human urine, sewage plants, and surface water was summarized. It is shown that the concentration of pharmaceuticals in human urine is usually 2–3 orders of magnitude higher than that in sewage plants and surface water. Then, the research progress of various technologies to treat pharmaceutical contaminants in urine was analyzed and compared, indicating the promise of advanced oxidation technologies to treat such wastewater, among which electrochemical oxidation has received widespread attention due to its advantages of cleanness, flexibility, and controllability. Therefore, the research progress of electrode materials and electrochemical technology to treat urine was reviewed, and finally, the future development direction was proposed, namely, coupling membrane treatment technology with intellectual development, which will help realize the scale and industrialization of source-separated urine treatment.

Construction of Clostridium tyrobutyricum strain and ionic membrane technology combination pattern for refinery final molasses recovery and butyric acid production.

Clostridium tyrobutyricum has considerable prospect in the production of organic acids. Globally, refinery final molasses is rich in sugar and reported to have high levels of accumulation and high emission costs, recognized as an excellent substrate for C. tyrobutyricum fermentation, but there is no suitable method available at present. In this study, an acid-base treatment combined with a new green membrane treatment technology - a dynamic ion-exchange membrane -was used to pretreat refinery final molasses, so that it could be used for C. tyrobutyricum to produce butyric acid. A high-performance liquid chromatography method was established to determine the conversion of a large amount of sucrose into fermentable sugars (71.88 g/L glucose and 38.06 g/L fructose) in the treated refinery final molasses. The process of sequential filtration with 3, 1, and 0.45 μm-pore diameter dynamic ion-exchange membranes could remove impurities, pigments, and harmful substances from the refinery final molasses, and retain the fermentable sugar. This means that refinery final molasses from the sugar industry could be utilized as a high-value by-product and used for the growth of C. tyrobutyricum, with industrial feasibility and economic competitiveness. Using the treated refinery final molasses as a carbon source, C. tyrobutyricum was screened by the method of adaptive evolution. The strain with butyric acid yielded 52.54 g/L, and the yield of the six carbon sugar was increased from 0.240 to 0.478 g/g. The results showed that combination of C. tyrobutyricum and ionic membrane technology broke through the bottleneck of its utilization of refinery final molasses. This study provided an innovative idea for the C. tyrobutyricum fermentation to produce butyric acid.

Advances in research of Anammox process in MBR

Membrane bioreactor (MBR) is an efficient wastewater treatment technology, which is produced by combining membrane treatment technology and biological treatment technology, and has the characteristics of stable water quality and shock load resistance, and has been widely used in domestic wastewater treatment. Anaerobic ammonia oxidation (ANAMMOX) is a new type of biological denitrification technology with the advantages of low energy consumption, low oxygen demand, carbon source saving and good economic benefits. This paper introduces the principle and characteristics of the MBR nitrification-anaerobic ammonia oxidation reactor process analysis process. Prospects of anaerobic ammonia oxidation technology in MBR are foreseen.

Membrane Treatment Technology Improves the Level of Municipal Sewage Treatment

Membrane Treatment Technology Improves the Level of Municipal Sewage Treatment

Preparation of carbon nanotubes/TiO2-polyvinylidene fluoride nanocomposites and composite films

Abstract In this paper, PVDF membrane was discussed, many modified materials were found from the shortage of materials, and finally carbon nanotubes/TiO2 hybrid materials were synthesized. The preparation methods and synthesis conditions of carbon nanotubes/TiO2-polyvinylidene fluoride nano composite ultrafiltration membrane were studied, and the advanced membrane treatment technology was prospected. Secondly, multi-walled carbon nanotubes/Ti02 hybrid materials were synthesized by hydrothermal method and sol-gel method.

A study of inline chemical coagulation/precipitation-ceramic microfiltration and nanofiltration for reverse osmosis concentrate minimization and reuse in the textile industry.

Reverse osmosis concentrate (ROC) is one of the major drawbacks in membrane treatment technologies specifically due to the scale-forming ions. It is important to remove these ions from ROC to enhance total water recovery and reuse in the textile industry that is the largest water-consumer and polluter industry. In this work, coagulation/high pH precipitation (CP) integrated with ceramic microfiltration (CMF) was studied as a pre-treatment method followed by nanofiltration (NF) to increase the efficiency of water recovery. To prevent organic fouling, ferric chloride (FeCl3) was applied at a concentration of 3 mM, and ceramic membranes were used for the removal of non-precipitating crystals and/or suspended solids (at high pH) before the NF processes. The CP-CMF method successfully removed calcium (Ca2+), magnesium (Mg2+), silica (SiO2), and TOC up to 97, 83, 92, and 87% respectively, which resulted in higher performance of the NF process. Moreover, this method provided higher flux at lower pressure that ultimately increased overall water recovery of the NF process to achieve near-zero liquid discharge (n-ZLD). A cost-benefit estimation showed that a high-quality effluent (COD<5 mg/L; conductivity 700<μS/cm; negligible residual color) can be generated and recycled in the textile industry at an economical cost (approximately 0.97 USD/m3). Therefore, ROC minimization and water recovery can help to achieve n-ZLD using the CP-CMF/NF method.

Estimation of membrane fouling and its alleviation with novel biocidal silver coordinated metallosurfactant cleaning solution

Membrane separation using polymeric membranes has evolved as a potent treatment technology for handling ubiquitous emulsified oily waste streams to prevent inadmissible water pollution. Nonetheless, this technology suffers from major bottlenecks i.e. oil fouling and biofouling, which significantly limit its widespread application. Hence, to make this membrane treatment technology sustainable, fouling mitigation is of paramount importance. Henceforth, the scope of the present study is of two-folds. The primary focus is to theoretically investigate the nature of oil fouling with two different polymeric membranes, polyethersulfone (PES) and polysulfone (PSf) during the emulsified feedstock treatment through conventional fouling model. Secondly, for mitigation of fouling, the study elaborates on the formulation and characterization of a novel membrane cleaning agent by coordinating silver into conventional surfactant sodium dodecyl sulfate (SDS). It was observed that the overall fouling propensity of the PSf membrane was 8% higher than that of the PES membrane, which was validated by the model fitting with the cake layer and standard-pore blocking fouling models discussed in the study. However, a higher tendency of the irreversible standard pore-blocking was exhibited by the PES membrane. To alleviate such intrinsic fouling, conventional membrane cleaning agents like sodium hydroxide, sodium hypochlorite, and SDS showed inefficiency by portraying very low permeate flux recovery. However, the prepared silver induced metallocomplex (AgS2) at a very low concentration (0.7 mM) was found with remarkable cleaning potential along with high resistance to biofilm development, showing around 100% and 97% flux recovery for both PES and PSf membrane, respectively. Further, it was also observed that after cleaning with AgS2, cleaned membranes exhibited minimal fouling and bio-fouling propensity for consecutive 9 and 6 cycles of continuous operation, respectively on account of the self-cleaning and anti-biofouling property of metallosurfactant. The profit to cost ratio for AgS2 metallosurfactant (PCAgS2) is found as 3.23, which is almost two times higher than the profit to cost ratio for conventional SDS cleaning (PCSDS = 1.63). Such high fold increase in the profit to cost ratio with AgS2 attributes to an economic operational cost compared to conventional SDS cleaning. Henceforth, it was significantly noted that with the formulated novel metallosurfactant AgS2, one can reduce the washing cycle during membrane operation and subsequently increase the membrane longevity by controlling the irreversible fouling/ biofouling. This will eventually reduce both the process cost of the oily wastewater treatment and membrane replacement cost.

Toward enhancing the chlorine resistance of forward osmosis membranes: an effective strategy via grafting cyclohexylamine

Abstract The forward osmosis (FO) membrane exhibits great performance degradation when contacting with chlorine solutions. The damage of chlorine to membrane material will seriously reduce the lifetime of the membrane and increase the cost of membrane treatment technology. Here, we prepared chlorine-stable membranes by a covalent modification method with cyclohexylamine. The cyclohexylamine observably changed the surface morphology, the roughness (arithmetic average) of the membrane decreased from 22 to 17.2 nm. The addition of cyclohexylamine produced a denser sacrificial layer of short chain polyamide, which made modified membranes possess significantly better chlorine resistance with slightly declined water flux. The water flux of the optimal modified membrane was 10.78 Lm−2 h−1, only 13% less than that of the pristine membrane. Importantly, after 20,000 ppm·h chlorine exposure, the membrane with 1.5 wt% cyclohexylamine had a salt rejection of 77.2% and showed 26.0% lower water flux than pristine TFC (thin film composite) membrane in FO mode. Notably, the grafting membranes could maintain a high performance under acidic chlorination conditions. The membrane with best performance had a salt rejection of 81.6%, exhibiting 24.4% higher salt rejection than pristine membrane with 20,000 ppm·h chlorine exposure at a pH of 4. The cyclohexylamine endowed the FO membrane with better chlorine resistance, making it attractive for the development of chlorine-resistant membrane for environmental and desalination processes.

Global trends and prospects in the removal of pharmaceuticals and personal care products: A bibliometric analysis

This study examined 9066 publications on the removal of pharmaceuticals and personal care products (PPCPs) published between 1998 and 2019 through a bibliometric approach based on the SCIE and SSCI databases. The overall research distribution of PPCPs, characteristics of pollutants, water pollution types, and up-to-date treatment technologies were revealed. The results showed that the number of articles relating to the removal of PPCPs increased significantly, with China contributing the most, followed by the United States and Spain. Water Research is the most productive journal, and the h-index is the highest (110). Five clusters were identified from the keyword network, namely polluted water types, biological treatment, adsorption, advanced oxidation, and membrane treatment technology. Through the elaboration of clustering and its relationship, it was found that research and development of technologies were the main concerns, and the application of adsorption technology was the most extensive. The most commonly used adsorbent is carbon material, while nanomaterial and biomaterial adsorbent are promising. These findings help to identify the global trend of PPCPs removal and provide valuable references for further research in this area.

Study on The Relationship Between Silt Density Index and Turbidity in Wastewater Membrane Treatment

With the development of the city, the problem of wastewater is becoming more and more serious. In wastewater treatment, membrane treatment technology is becoming more and more mature. In membrane treatment technology, the SDI value of filtered water is a key indicator to show the treatment capacity, which has a great relationship with the turbidity of sewage. In this paper, the relationship between turbidity and SDI of effluent was studied in the same membrane treatment.

Study on preparation of metal-organic framework membrane and pore size adjustment method

Metal-organic framework materials have the advantages of large specific surface area, high porosity, strong adjustability of framework structure, adjustable chemical and thermal properties, etc., and can be used as ideal membrane materials. In this paper, the preparation methods and conditions of several common metal-organic framework materials, as well as how to adjust the pore size, are reviewed, and the advanced membrane treatment technology is prospected.

Membrane Treatment: Operators Need to Understand Critical Concepts

The number of potable reuse projects in the United States has increased the need for operators who are knowledgeable about advanced water treatment processes, including membrane treatment technologies.

Environmental impact of carbon cross-media metabolism in waste management: A case study of municipal solid waste treatment systems in China

Waste treatment is a metabolic process that incurs pollutants migration across environmental media (i.e., air, water, and soil) and involves various conversions of physicochemical forms of carbon. Multiple forms of carbon compounds, such as CO2, CH4, CO, VOCs, and other organic matter can contribute to a series of transboundary environmental problems. However, current strategies targeting pollution reduction in single medium may cause pollution transfer to other environmental media, leading to comparatively large difficulty in assessing the related environmental impact on integrated ecosystems. This paper develops an analysis framework of carbon cross-media metabolism in municipal solid waste (MSW) treatment systems that include landfilling, composting, incineration, and anaerobic digestion. Life cycle impact analysis and sensitivity analysis methods are used to recognize the essential technologies in promoting the carbon cross-media migration and decreasing the integrated environmental impacts. The framework is implemented in a case study of the MSW treatment systems of 2013 in China. Results show that 86%–98% of carbon pollutants generated through landfilling, composting, and incineration ended up in the natural environment, while anaerobic digestion achieved an 87% pollution removal rate. Co-generation technology applied in incineration flue gas treatment, biochemical + membrane treatment technology in wastewater treatment, and co-processing of sludge in cement kilns were identified as the essential technologies affecting carbon migration across the gas-liquid, liquid-solid, and solid-gas interface, respectively. The relatively high environmental impacts of landfilling and incineration can be decreased by optimizing their technological compositions and applications. This study can provide support to replace the traditional environmental practice aiming at pollution control in single environmental medium independently by a systematic management approach that considers carbon cross-media metabolism and integrated environmental impact.

Recent Advances in Water and Wastewater Treatment with Emphasis in Membrane Treatment Operations

The present Special Issue brought together recent research findings from renowned scientists in this field and assembled contributions on advanced technologies that have been applied to the treatment of wastewater and drinking water, with an emphasis on novel membrane treatment technologies. The 12 research contributions highlight various processes and technologies that can achieve the effective treatment and purification of wastewater and drinking water, aiming (occasionally) for water reuse. The published papers can be classified into three major categories. (a) First, there are those that investigate the application of membrane treatment processes, either directly or in hybrid processes. The role of organic matter presence and fouling control is the main aim of the research in some of these studies. (b) Second, there are studies that investigate the application of adsorptive processes for the removal of contaminants from waters, such as arsenic, antimony, or chromate, with the aim of the efficient removal of the toxic contaminants from water or wastewater. (c) Lastly, there are studies that include novel aspects of oxidative treatment such as bubbleless ozonation.

Recovery of cooling tower blowdown water for reuse: The investigation of different types of pretreatment prior nanofiltration and reverse osmosis

The suitability of two different pretreatment methods, i.e., coagulation-filtration and ultrafiltration (UF), and two final membrane treatment technologies, namely nanofiltration (NF) and reverse osmosis (RO), for desalination of a cooling tower blowdown (CTBD) was investigated. Particular attention was paid to ensuring that the best pretreatment method could enhance the permeate flux and lifespan of the NF and RO membranes and decrease the membranes' fouling characteristics. Furthermore, the difference of NF and RO performances in CTBD treatment was investigated.In order to find the most appropriate type of coagulant, coagulant dosage, pH and co-coagulant dosage, 21 jar tests were performed. The results showed that 50mg/L of Polyaluminium chloride (PACl) in the presence of 0.5ppm co-coagulant in pH of 6.5–7.5 has the best treatment performance. Silt density index (SDI), chemical oxygen demand (COD), turbidity, electrical conductivity, and membrane permeate flux tests were performed for both pretreatment and treatment stages. Both pretreatment methods produced appropriate feed for NF and RO in terms of SDI and turbidity. Using the coagulation–filtration pretreated water instead of raw water as a feed for NF and RO membranes showed about a 25 and 33 percent improvement in permeate flux after 100min in 10 and 15bar applied pressure for NF and RO, respectively.

A group decision-making tool for the application of membrane technologies in different water reuse scenarios

A global challenge of increasing concern is diminishing fresh water resources. A growing practice in many communities to supplement diminishing fresh water availability has been the reuse of water. Novel methods of treating polluted waters, such as membrane assisted technologies, have recently been developed and successfully implemented in many places. Given the diversity of membrane assisted technologies available, the current challenge is how to select a reliable alternative among numerous technologies for appropriate water reuse. In this research, a fuzzy logic based multi-criteria, group decision making tool has been developed. This tool has been employed in the selection of appropriate membrane treatment technologies for several non-potable and potable reuse scenarios. Robust criteria, covering technical, environmental, economic and socio-cultural aspects, were selected, while 10 different membrane assisted technologies were assessed in the tool. The results show this approach capable of facilitating systematic and rigorous analysis in the comparison and selection of membrane assisted technologies for advanced wastewater treatment and reuse.