scholarly journals A Hybrid Ion-Exchange Fabric/Ceramic Membrane System to Remove As(V), Zn(II), and Turbidity from Wastewater

2020 ◽  
Vol 10 (7) ◽  
pp. 2414
Author(s):  
Nag-Choul Choi ◽  
Kang-Hee Cho ◽  
Min-Sung Kim ◽  
Seong-Jik Park ◽  
Chang-Gu Lee

Ceramic membranes and ion exchangers are effective at removing turbidity and ionic contaminants from water, respectively. In this study, we demonstrate the performance of a hybrid ion-exchange fabric/ceramic membrane system to treat metal ions and turbidity at the same time in synthetic wastewater. The removal rate of As(V) and Zn(II) by the ceramic membrane increased with solution pH, while turbidity was completely removed regardless of the solution pH. The main reaction of As(V) removal was adsorption at solution pH 6 and precipitation at solution pH 8, whereas phase-change was the predominant reaction for Zn(II) removal at both solution pH values. The removal efficiency of the ion-exchange fabric was affected by the solution pH, with the maximum removal capacity of As(V) occurring at solution pH 4. The As(V) adsorption capacity of the ion-exchange fabric reached equilibrium within 120 min. The ion-exchange capacity of the ion-exchange fabric was compared with commercial ion-exchange fibers. The regeneration efficiency of the ion-exchange fabric using 0.1 M NaCl solution was around 95% on average and decreased slightly as the number of regeneration cycles was increased. Over 80% of As(V) and Zn(II) were steadily removed at solution pH 6 by the hybrid ion-exchange fabric/ceramic membrane system. Reduced flow rate and removal capacity were recovered through a backwashing process during continuous treatment with the hybrid ion-exchange fabric/ceramic membrane system.

2019 ◽  
Vol 14 (2) ◽  
pp. 289-296 ◽  
Author(s):  
H. Noguchi ◽  
M. H. Oo ◽  
T. Niwa ◽  
E. Fong ◽  
R. Yin ◽  
...  

Abstract PUB, Singapore's National Water Agency, has been using polymeric UF membrane in drinking water plants to produce high quality water whilst requiring a smaller footprint. Submerged polymeric hollow-fiber membrane has been used since 2003 in Chestnut Avenue Water Works (CAWW). PUB decided to use submerged-type ceramic membranes for enhancement of production capacity at CAWW. The flat-sheet ceramic membrane system was retrofitted into two spare, empty tanks with a combined design capacity of 36,400 m3/d. The system has been successfully put into operation, running at a net flux of 160 L/m2-h (LMH) since June 2017. Membrane integrity testing is automatically carried out once a week to ensure the membranes' integrity. Stable filtrate quality has been achieved with a low turbidity of 0.018 NTU on average. Pretreatment for seawater desalination is another application in which a ceramic membrane system can be operated at higher flux compared to that for polymeric membranes. A pilot scale system was installed at PUB R&D facility in Tuas to investigate sustainable operating flux and permeate quality. FeCl3 was used as a coagulant before ceramic filtration, with a dosage of 4–6 mg/L. It was shown that sustainable flux can be 181–249 LMH in seawater treatment system with flat sheet ceramic membranes. The silt density index and turbidity of permeate were 1.6–2.2 and 0.04–0.10 NTU, respectively, which indicates that the system can produce high quality water for feed of reverse osmosis systems.


Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 180
Author(s):  
Shaobin Sun ◽  
Hong Yao ◽  
Xinyang Li ◽  
Shihai Deng ◽  
Shenlong Zhao ◽  
...  

Pharmaceutical residuals are increasingly detected in natural waters, which made great threat to the health of the public. This study evaluated the utility of the photo-Fenton ceramic membrane filtration toward the removal and degradation of sulfamethoxazole (SMX) as a model recalcitrant micropollutant. The photo-Fenton catalyst Goethite (α-FeOOH) was coated on planar ceramic membranes as we reported previously. The removal of SMX in both simulated and real toilet wastewater were assessed by filtering the feed solutions with/without H2O2 and UV irradiation. The SMX degradation rate reached 87% and 92% respectively in the presence of UV/H2O2 for the original toilet wastewater (0.8 ± 0.05 ppb) and toilet wastewater with a spiked SMX concentration of 100 ppb. The mineralization and degradation by-products were both assessed under different degradation conditions to achieve deeper insight into the degradation mechanisms during this photo-Fenton reactive membrane filtration. Results showed that a negligible removal rate (e.g., 3%) of SMX was obtained when only filtering the feed solution through uncoated or catalyst-coated membranes. However, the removal rates of SMX were significantly increased to 67% (no H2O2) and 90% (with H2O2) under UV irradiation, respectively, confirming that photo-Fenton reactions played the key role in the degradation/mineralization process. The highest apparent quantum yield (AQY) reached up to approximately 27% when the H2O2 was 10 mmol·L−1 and UV254 intensity was 100 μW·cm−2. This study lays the groundwork for reactive membrane filtration to tackle the issues from micropollution.


2012 ◽  
Vol 7 (4) ◽  
Author(s):  
Gilbert Galjaard ◽  
Jonathan Clement ◽  
Wui Seng Ang ◽  
Mong Hoo Lim

Ceramic membrane technology is used in water treatment due to the robustness of ceramic membranes, but ceramic membrane systems are costly as each membrane module is housed in individual casing. PWNT has developed a ceramic membrane system called the CeraMac which greatly reduced the capital cost of installing the system by housing up to 200 modules in a single stainless steel vessel. PWNT and PUB have jointly started a 18-month operation at Choa Chu Kang Waterworks (CCKWW). In this paper, the results of the optimization runs using settled water as feed has shown that membrane operation at flux of 200 lmh can be sustained with stable transmembrane pressure (TMP) and permeability, and the proposal to apply 0.5 mg/L residual ozone to the feed to investigate the effect of ozonated feed on membrane operational performance and fouling will be discussed.


2021 ◽  
Vol 10 (16) ◽  
pp. e121101623331
Author(s):  
Kepler Borges França ◽  
Adriana Barbosa da Costa Pereira ◽  
Cristiane Rodrigues Macêdo ◽  
Carolina Pereira Dantas ◽  
Karine Oliveira da Costa

The management of produced water is a huge challenge for oil companies, as environmental agencies use increasingly strict laws and require a primary treatment for the disposal of waste. The conventional methods used in the treatment of oily water, cannot satisfactorily remove the environmental laws. A system is presented, with a hydrocyclone built within LABDES/UFCG, tested and characterized with oily waters with different levels of oil concentrations, in order to study its efficiency. It was observed that for different oil concentrations in the hydrocyclone feed stream of (100 to 2000) mg L-1, total oil and grease, reached an efficiency above 85%. The set of ceramic membranes, MR01-10 and MR02-20, with porosities of 43% and 52%, were used in the assembly of two types of systems, SMC-DE and SMC-FC. SMC-FC showed a removal rate above 80% for an average production of 165 L h-1 m-2. However, SMC-DE proved to be more efficient in relation to TOG, above 98%, but less efficient in relation to the permeate production flow, 63.3 L h-1.m-2. The hydrocyclone system with cross-flow ceramic membrane (SH-MC/FC) was chosen to study the reduction of oil in oily water, for a concentration range of (200 to 2000) mg L-1, which presented a removal rate above 95%.


1998 ◽  
Vol 38 (8-9) ◽  
pp. 179-188 ◽  
Author(s):  
K. F. Janning ◽  
X. Le Tallec ◽  
P. Harremoës

Hydrolysis and degradation of particulate organic matter has been isolated and investigated in laboratory scale and pilot scale biofilters. Wastewater was supplied to biofilm reactors in order to accumulate particulates from wastewater in the filter. When synthetic wastewater with no organic matter was supplied to the reactors, hydrolysis of the particulates was the only process occurring. Results from the laboratory scale experiments under aerobic conditions with pre-settled wastewater show that the initial removal rate is high: rV, O2 = 2.1 kg O2/(m3 d) though fast declining towards a much slower rate. A mass balance of carbon (TOC/TIC) shows that only 10% of the accumulated TOC was transformed to TIC during the 12 hour long experiment. The pilot scale hydrolysis experiment was performed in a new type of biofilm reactor - the B2A® biofilter that is characterised by a series of decreasing sized granular media (80-2.5 mm). When hydrolysis experiments were performed on the anoxic pilot biofilter with pre-screened wastewater particulates as carbon source, a rapid (rV, NO3=0.7 kg NO3-N/(m3 d)) and a slowler (rV, NO3 = 0.3 kg NO3-N/(m3 d)) removal rate were observed at an oxygen concentration of 3.5 mg O2/l. It was found that the pilot biofilter could retain significant amounts of particulate organic matter, reducing the porosity of the filter media of an average from 0.35 to 0.11. A mass balance of carbon shows that up to 40% of the total incoming TOC accumulates in the filter at high flow rates. Only up to 15% of the accumulated TOC was transformed to TIC during the 24 hour long experiment.


Author(s):  
Jiwei Zhang ◽  
Jingjing Xu ◽  
Shuaixia Liu ◽  
Baoxiang Gu ◽  
Feng Chen ◽  
...  

Background: Coal gangue was used as a catalyst in heterogeneous Fenton process for the degradation of azo dye and phenol. The influencing factors, such as solution pH gangue concentration and hydrogen peroxide dosage were investigated, and the reaction mechanism between coal gangue and hydrogen peroxide was also discussed. Methods: Experimental results showed that coal gangue has the ability to activate hydrogen peroxide to degrade environmental pollutants in aqueous solution. Under optimal conditions, after 60 minutes of treatment, more than 90.57% of reactive red dye was removed, and the removal efficiency of Chemical Oxygen Demand (COD) up to 72.83%. Results: Both hydroxyl radical and superoxide radical anion participated in the degradation of organic pollutant but hydroxyl radical predominated. Stability tests for coal gangue were also carried out via the continuous degradation experiment and ion leakage analysis. After five times continuous degradation, dye removal rate decreased slightly and the leached Fe was still at very low level (2.24-3.02 mg L-1). The results of Scanning Electron Microscope (SEM), energy dispersive X-Ray Spectrometer (EDS) and X-Ray Powder Diffraction (XRD) indicated that coal gangue catalyst is stable after five times continuous reuse. Conclusion: The progress in this research suggested that coal gangue is a potential nature catalyst for the efficient degradation of organic pollutant in water and wastewater via the Fenton reaction.


Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 369
Author(s):  
Shengji Xia ◽  
Xinran Zhang ◽  
Yuanchen Zhao ◽  
Fibor J. Tan ◽  
Pan Li ◽  
...  

The membrane separation process is being widely used in water treatment. It is very important to control membrane fouling in the process of water treatment. This study was conducted to evaluate the efficiency of a pre-oxidation-coagulation flat ceramic membrane filtration process using different oxidant types and dosages in water treatment and membrane fouling control. The results showed that under suitable concentration conditions, the effect on membrane fouling control of a NaClO pre-oxidation combined with a coagulation/ceramic membrane system was better than that of an O3 system. The oxidation process changed the structure of pollutants, reduced the pollution load and enhanced the coagulation process in a pre-oxidation-coagulation system as well. The influence of the oxidant on the filtration system was related to its oxidizability and other characteristics. NaClO and O3 performed more efficiently than KMnO4. NaClO was more conducive to the removal of DOC, and O3 was more conducive to the removal of UV254.


2018 ◽  
Vol 20 ◽  
pp. 16-33 ◽  
Author(s):  
J. Saraiva de Souza ◽  
S. José dos Santos Filho ◽  
Severino Rodrigues de Farias Neto ◽  
A.G. Barbosa de Lima ◽  
H.A. Luma Fernandes Magalhães

Innovative technologies are needed to attend the increasingly strict requirements for produced water treatment, since most of the separation processes are limited to particles larger than 10 μm. Separation processes using ceramic membranes are attracting great interest from academic and industrial community. Nevertheless, few studies, especially numerical, regarding the inorganic membrane’s application for the polluted water separation have been reported. In the present work, therefore, a study of fluid-flow dynamics for a laminar regime in porous tubes (tubular porous ceramic membrane) has been performed. The mass, momentum and mass transport conservation equations were solved with the aid of a structured mesh using ANSYS CFX commercial package. The velocity of local permeation was determined using the resistance in series model. The specific resistance of the polarized layer was obtained by Carman-Kozeny equation. The numerical results were evaluated and compared with the results available in the literature, where by a good agreement with each other was found. The numerical results, obtained by the proposed shell and tubular membrane separation module, indicate that there is facilitation of mass transfer and hence a reduction in the thickness of the polarized boundary layer occurs.


1987 ◽  
Vol 60 (6) ◽  
pp. 2215-2219 ◽  
Author(s):  
Yutaka Hirata ◽  
Masashi Date ◽  
Yukiko Yamamoto ◽  
Akira Yamauchi ◽  
Hideo Kimizuka

2016 ◽  
Author(s):  
A. Ribeiro ◽  
C. Vilarinho ◽  
J. Araújo ◽  
J. Carvalho

The increasing of world population, industrialization and global consuming, existing market products existed in the along with diversification of raw materials, are responsible for an exponential increase of wastes. This scenario represents loss of resources and ultimately causes air, soils and water pollution. Therefore, proper waste management is currently one of the major challenges faced by modern societies. Textile industries represents, in Portugal, almost 10% of total productive transforming sector and 19% of total employments in the sector composed by almost 7.000 companies. One of the main environmental problems of textile industries is the production of significant quantities of wastes from its different processing steps. According to the Portuguese Institute of Statistics (INE) these industries produce almost 500.000 tons of wastes each year, with the textile cotton waste (TCW) being the most expressive. It was estimated that 4.000 tons of TCW are produced each year in Portugal. In this work an integrated TCW valorisation procedure was evaluated, firstly by its thermal and energetic valorisation with slow pyrolysis followed by the utilization of biochar by-product, in lead and chromium synthetic wastewater decontamination. Pyrolysis experiments were conducted in a small scale rotating pyrolysis reactor with 0.1 m3 of total capacity. Results of pyrolysis experiments showed the formation of 0,241 m3 of biogas for each kilogram of TCW. Results also demonstrated that the biogas is mostly composed by hydrogen (22%), methane (14 %), carbon monoxide (20%) and carbon dioxide (12%), which represents a total high calorific value of 12.3 MJ/Nm3. Regarding biochar, results of elemental analysis demonstrated a high percentage of carbon driving its use as low cost adsorbent. Adsorption experiments were conducted with lead and chromium synthetic wastewaters (25, 50 and 100 mg L−1) in batch vessels with controlled pH. It was evaluated the behaviour of adsorption capacity and removal rate of each metal during 120 minutes of contact time using 5, 10 and 50 g L−1 of adsorbent dosage. Results indicated high affinity of adsorbent with each tested metal with 78% of removal rate in chromium and 95% in lead experiments. This suggests that biochar from TCW pyrolysis may be appropriated to wastewaters treatment, with high contents of heavy metals and it can be an effective alternative to activated carbon.


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