Tanning Wastewater Treatment by Ultrafiltration: Process Efficiency and Fouling Behavior

Ultrafiltration is a promising, environment-friendly alternative to the current physicochemical-based tannery wastewater treatment. In this work, ultrafiltration was employed to treat the tanning wastewater as an upstream process of the Zero Liquid Discharge (ZLD) system in the leather industry. The filtration efficiency and fouling behaviors were analyzed to assess the impact of membrane material and operating conditions (shear rate on the membrane surface and transmembrane pressure). The models of resistance-in-series, fouling propensity, and pore blocking were used to provide a comprehensive analysis of such a process. The results show that the process efficiency is strongly dependent on the operating conditions, while the membranes of either PES or PVDF showed similar filtration performance and fouling behavior. Reversible resistance was the main obstacle for such process. Cake formation was the main pore blocking mechanism during such process, which was independent on the operating conditions and membrane materials. The increase in shear rate significantly increased the steady-state permeation flux, thus, the filtration efficiency was improved, which resulted from both the reduction in reversible resistance and the slow-down of fouling layer accumulate rate. This is the first time that the fouling behaviors of tanning wastewater ultrafiltration were comprehensively evaluated, thus providing crucial guidance for further scientific investigation and industrial application.

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Performance Evaluation of Polymeric Membrane Permeability Characteristics Using Different Aqueous Solutions

Quality of Life (Banja Luka) - APEIRON ◽

10.7251/qol2103093m ◽

2021 ◽

Vol 21 (3) ◽

Author(s):

Erhan Mustafa ◽

Katerina Atkovska ◽

Stefan Kuvendziev ◽

Mirko Marinkovski ◽

Kiril Lisichkov

Keyword(s):

Wastewater Treatment ◽

Aqueous Solutions ◽

Membrane Permeability ◽

Membrane Filtration ◽

Membrane Surface ◽

Process Efficiency ◽

Polymeric Membrane ◽

Transmembrane Pressure ◽

Permeability Characteristics ◽

Dead End

In the last decade the application of membrane separation technology is more increasing. The membrane in water purification and wastewater treatment is essential separation process used for water reclamation. The production of new membrane types with different permeable characteristics and performances allows them to be fitted in different membrane modules that can be used in the membrane filtration. The water characteristics are important for the membrane performance. It can seriously affect the permeability characteristics and increase the fouling on the membrane surface. In wastewater treatment, the characteristics of the aqueous influent can reduce the permeability of the membrane and the process efficiency of the membrane bioreactor (MBR). The aim of this paper is to explore the effect of different aqueous solutions on membrane permeability using dead end filtration process. For this purpose, NaCl solution with different concentration were prepared and the effect of the concentration polarization on the membrane was observed. The constructed membrane module was also tested with real water sample and the membrane permeability was analyzed. In this experiment a polymeric membrane produced from polyether sulphonate (PES), with diameter of 5.0 cm and pore size of 0.04 µm was assembled in a constructed module for dead-end filtration. The module was constructed in a way that would allow turbulence of the solution on the membrane surface. The following working parameters were examined: transmembrane pressure (TMP), the types of solutions, the working temperature, and the influence of agitation on the feeding to the specific membrane flux and permeability. The results showed that the membrane permeability is affected by the water organic and inorganic constituents and in the process of design of membrane reactor for wastewater treatment, the water composition should be taken in consideration.

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Impact of FO Operating Pressure and Membrane Tensile Strength on Draw-Channel Geometry and Resulting Hydrodynamics

Membranes ◽

10.3390/membranes10050111 ◽

2020 ◽

Vol 10 (5) ◽

pp. 111

Author(s):

Alexander J. Charlton ◽

Boyue Lian ◽

Gaetan Blandin ◽

Greg Leslie ◽

Pierre Le-Clech

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Reynolds Number ◽

Shear Rate ◽

Membrane Surface ◽

Forward Osmosis ◽

Transmembrane Pressure ◽

Channel Height ◽

Operating Pressure ◽

Channel Geometry

In an effort to improve performances of forward osmosis (FO) systems, several innovative draw spacers have been proposed. However, the small pressure generally applied on the feed side of the process is expected to result in the membrane bending towards the draw side, and in the gradual occlusion of the channel. This phenomenon potentially presents detrimental effects on process performance, including pressure drop and external concentration polarization (ECP) in the draw channel. A flat sheet FO system with a dot-spacer draw channel geometry was characterized to determine the degree of draw channel occlusion resulting from feed pressurization, and the resulting implications on flow performance. First, tensile testing was performed on the FO membrane to derive a Young’s modulus, used to assess the membrane stretching, and the resulting draw channel characteristics under a range of moderate feed pressures. Membrane apex reached up to 67% of the membrane channel height when transmembrane pressure (TMP) of 1.4 bar was applied. The new FO channels considerations were then processed by computational fluid dynamics model (computational fluid dynamics (CFD) by ANSYS Fluent v19.1) and validated against previously obtained experimental data. Further simulations were conducted to better assess velocity profiles, Reynolds number and shear rate. Reynolds number on the membrane surface (draw side) increased by 20% and shear rate increased by 90% when occlusion changed from 0 to 70%, impacting concentration polarisation (CP) on the membrane surface and therefore FO performance. This paper shows that FO draw channel occlusion is expected to have a significant impact on fluid hydrodynamics when the membrane is not appropriately supported in the draw side.

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Cost-effective removal of COD in the pre-treatment of wastewater from the paper industry

Water Science & Technology ◽

10.2166/wst.2019.328 ◽

2019 ◽

Vol 81 (7) ◽

pp. 1345-1353 ◽

Cited By ~ 2

Author(s):

Joanna Boguniewicz-Zablocka ◽

Iwona Klosok-Bazan ◽

Vincenzo Naddeo ◽

Clara A. Mozejko

Keyword(s):

Wastewater Treatment ◽

High Efficiency ◽

Paper Industry ◽

Cost Effective ◽

Operating Conditions ◽

Cod Removal ◽

Process Efficiency ◽

Effective Removal ◽

Initial Ph ◽

Pre Treatment

Abstract The present paper reveals results of research for cost-effective removal of chemical oxygen demand (COD) contained in industrial paper mill effluent. Not only process efficiency but also wastewater treatment costs are discussed. Different pre-treatment processes are applied aiming to investigate the COD removal before discharge to the municipal sewage network. The objective of this paper is to find the optimal operating conditions for the coagulation process. The effects of key operational parameters, including the type of coagulant, initial pH, temperature and coagulant dose, on COD percentage removal were investigated. The laboratory experiments confirmed the high efficiency of chemically enhanced mechanical treatment towards COD. The data obtained show that even low dose of chemicals provides sufficient COD reduction. The initial pH of the wastewater had a significant impact on the COD removal. Under the optimal operational conditions (pH = 7.5, T = 18 °C) the treatment of wastewater from paper industries by coagulation has led to a reduction of 70% COD for wastewater discharged. In terms of the investigated paper industry wastewater, polyaluminium chloride appears to be most suitable for treatment of high COD concentration. However, in an economic evaluation of requirements for wastewater treatment, operating costs and associated saving were such that PAX was more favourable.

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Air Backwash Efficiency on Organic Fouling of UF Membranes Applied to Shellfish Hatchery Effluents

Membranes ◽

10.3390/membranes8030048 ◽

2018 ◽

Vol 8 (3) ◽

pp. 48 ◽

Cited By ~ 5

Author(s):

Clémence Cordier ◽

Christophe Stavrakakis ◽

Patrick Sauvade ◽

Franz Coelho ◽

Philippe Moulin

Keyword(s):

Membrane Surface ◽

Operating Conditions ◽

Particle Removal ◽

Two Phase ◽

Significant Information ◽

Dead End ◽

Biodiversity Preservation ◽

Organic Fouling ◽

Uf Membranes ◽

The Impact

Among all the techniques studied to overcome fouling generated in dead-end filtration, the injection of air during backwashes proved to be the most effective. Indeed, shear stress engendered by the two-phase flow enhanced particle removal on membrane surface. This work aims to study the injection of air to drain the membranes before backwash. Firstly, the efficiency of this backwash procedure was evaluated during the ultrafiltration of seawater on a semi industrial pilot plant using different operating conditions. Then, the treatment of seawater, doped with oyster gametes to simulate the filtration of shellfish hatchery effluents, was performed to confirm the hydraulic performance of the air backwash. Indeed, the release of gametes, expulsed by exotic bivalves in the natural environment, could be a risk for the biodiversity preservation. The impact of air backwash on the integrity of oocytes and spermatozoa was identified using flow cytometry and microscopic analyses. When oyster gametes were added, their retention by ultrafiltration was validated. The impact of air backwash on these species viability was a significant information point for the implementation of this process on shellfish production farms.

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A Practical Methodology for Forecasting the Impact of Changes in Influent Loads and Discharge Consents on Average Energy Consumption and Sludge Production by Activated Sludge Wastewater Treatment

Sustainability ◽

10.3390/su132112293 ◽

2021 ◽

Vol 13 (21) ◽

pp. 12293

Author(s):

Catarina Silva ◽

Maria João Rosa

Keyword(s):

Wastewater Treatment ◽

Energy Consumption ◽

Activated Sludge ◽

Average Energy ◽

Oxygen Demand ◽

Operating Conditions ◽

Limit Values ◽

Oxygen Requirements ◽

The Impact ◽

Sludge Production

This paper proposes a simple and easy-to-use methodology for forecasting the impact of changes in influent chemical oxygen demand (COD) and in the emission limit values (ELVs) of COD and total nitrogen on average energy requirements for aeration and sludge production by activated sludge wastewater treatment plants (WWTPs). The methodology is based on mass balances of sludge production and oxygen requirements for carbonaceous material biodegradation and/or nitrification, oxygen transfer and aeration equipment efficiency. Using average values of historical data of regular monitoring (water quality and operating conditions) WWTP-specific equations of oxygen requirements, energy consumption and sludge production are derived as a function of influent COD and influent N-total, which may be used to quantify the impact of influent and ELV changes. The methodology was tested in five extended aeration WWTPs for three scenarios established by the utility. The results show that increasing influent COD, from 900 to 1300 mg/L, for example, significantly increases the energy consumption by 49% and sludge production by 53%. For influent 54–68 mg/L N-total, imposing 15 mgN/L ELV results in a 9–26% increase in energy consumption. The COD ELV change studied (season-specific, from 150 mg/L 12 months/year to 125 mg/L 8 months/year to 100 mg/L 4 months/year) increases the energy consumption by 1.8–2.6% and the sludge production by 4.3–5.4%.

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Clarification of 1,3-Propanediol Fermentation Broths by Using a Ceramic Fine UF Membrane

Membranes ◽

10.3390/membranes10110319 ◽

2020 ◽

Vol 10 (11) ◽

pp. 319 ◽

Cited By ~ 1

Author(s):

Wirginia Tomczak ◽

Marek Gryta

Keyword(s):

Membrane Distillation ◽

Process Efficiency ◽

Transmembrane Pressure ◽

Operational Parameters ◽

Simple Method ◽

In Series ◽

Pre Treatment ◽

The Cost ◽

Fermentation Broths ◽

The Impact

This work examined the use of a ceramic fine ultrafiltration (UF) membrane for the pre-treatment of 1,3-propanodiol (1,3-PD) fermentation broths. It has been demonstrated that the membrane used provides obtaining a high-quality, sterile permeate, which can be sequentially separated by other processes such as nanofiltration (NF) and membrane distillation (MD). Special attention was paid to the impact of the operational parameters on the membrane performance. The series of UF experiments under transmembrane pressure (TMP) from 0.1 to 0.4 MPa and feed flow rate (Q) from 200 to 400 dm3/h were performed. Moreover, the impact of the feed pH, in the range from 5 to 10, on the flux was investigated. It has been demonstrated that for fine UF, increasing the TMP is beneficial, and TMP equal to 0.4 MPa and Q of 400 dm3/h ensure the highest flux and its long-term stability. It has been shown that in terms of process efficiency, the most favorable pH of the broths is equal to 9.4. An effective and simple method of membrane cleaning was presented. Finally, the resistance-in-series model was applied to describe resistances that cause flux decline. Results obtained in this study can assist in improving the cost-effectiveness of the UF process of 1,3-PD fermentation broths.

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Modeling of H2 Permeation through Electroless Pore-Plated Composite Pd Membranes Using Computational Fluid Dynamics

Membranes ◽

10.3390/membranes11020123 ◽

2021 ◽

Vol 11 (2) ◽

pp. 123

Author(s):

Alberto Fernández ◽

Cintia Casado ◽

David Alique ◽

José Antonio Calles ◽

Javier Marugán

Keyword(s):

Fluid Dynamics ◽

Experimental Data ◽

Computational Fluid Dynamics ◽

Hydrogen Permeation ◽

Membrane Surface ◽

Molar Fraction ◽

Operating Conditions ◽

Cfd Modeling ◽

Wide Range ◽

The Impact

This work focused on the computational fluid dynamics (CFD) modeling of H2/N2 separation in a membrane permeator module containing a supported dense Pd-based membrane that was prepared using electroless pore-plating (ELP-PP). An easy-to-implement model was developed based on a source–sink pair formulation of the species transport and continuity equations. The model also included the Darcy–Forcheimer formulation for modeling the porous stainless steel (PSS) membrane support and Sieverts’ law for computing the H2 permeation flow through the dense palladium film. Two different reactor configurations were studied, which involved varying the hydrogen flow permeation direction (in–out or out–in). A wide range of experimental data was simulated by considering the impact of the operating conditions on the H2 separation, such as the feed pressure and the H2 concentration in the inlet stream. Simulations of the membrane permeator device showed an excellent agreement between the predicted and experimental data (measured as permeate and retentate flows and H2 separation). Molar fraction profiles inside the permeator device for both configurations showed that concentration polarization near the membrane surface was not a limit for the hydrogen permeation but could be useful information for membrane reactor design, as it showed the optimal length of the reactor.

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Study of flocculation with PONILIT GT-2 anionic polyelectrolyte applied into a chemical wastewater treatment

Open Chemistry ◽

10.2478/s11532-006-0057-6 ◽

2007 ◽

Vol 5 (1) ◽

pp. 239-256 ◽

Cited By ~ 5

Author(s):

Carmen Zaharia ◽

Rodica Diaconescu ◽

Mioara Surpăţeanu

Keyword(s):

Wastewater Treatment ◽

Mixing Time ◽

Oxygen Demand ◽

Ferric Sulfate ◽

Operating Conditions ◽

Color Removal ◽

Process Efficiency ◽

Ferric Ions ◽

Turbidity Removal ◽

Anionic Polyelectrolyte

AbstractThis paper discusses the applications of synthetic PONILIT GT-2 anionic polyelectrolyte in conjuction with ferric sulfate in a chemical wastewater treatment viz. wastewater from ceramics manufacturing. Synthetic wastewaters with different colloid concentrations were prepared and the coagulation-flocculation process followed by sedimentation and/or filtration was studied. Variables associated with the chemical wastewater composition, mixing time, and the coagulant and flocculant dose are considered in order to appreciate the process efficiency in terms of turbidity, chemical oxygen demand (COD), and color removal. The degrees are higher for turbidity and color (> 80 %) removal respectively, and, satisfactory for COD (3 type, considering ferric sulfate dose, polyelectrolyte dose, and mixing time as independent variables, while the turbidity and color removal efficiencies were chosen as optimization criteria. The empirical model was found adequate for the chemical wastewater treatment. Also, an analysis of the model was performed to find the optimal operating conditions, in order to apply this process for an efficient chemical wastewater treatment using ferric sulfate as coagulation agent and PONILIT GT-2 anionic polyelectrolyte as flocculation agent. The optimal values correspond to a ferric ions concentration of 6.093 mg/L, a polyelectrolyte dose of 0.651 mg/L, and a mixing time of 24.024 minutes for turbidity removal (95.869 %), respectively, and, to a ferric ions concentration of 6.01 mg/L, a polyelectrolyte dose of 0.69 mg/L, and a mixing time of 26 minutes for color removal (98.741 %).

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The Impact of Mechanically-Imposed Shear on Clogging, Fouling and Energy Demand for an Immersed Membrane Bioreactor

Membranes ◽

10.3390/membranes8040104 ◽

2018 ◽

Vol 8 (4) ◽

pp. 104 ◽

Cited By ~ 2

Author(s):

Simon Judd ◽

Albert Odai ◽

Pompilia Buzatu ◽

Hazim Qiblawey

Keyword(s):

Energy Demand ◽

Membrane Bioreactor ◽

Membrane Surface ◽

Petroleum Industry ◽

Pilot Scale ◽

Hollow Fibre ◽

Transmembrane Pressure ◽

Flat Sheet ◽

Industry Effluent ◽

The Impact

The impact of the application of mechanically-imposed shear on the propensity for fouling and clogging (or “sludging”—the agglomeration of sludge solids in the membrane channel) of an immersed flat sheet (iFS) membrane bioreactor (MBR) was studied. The bench-scale test cell used contained a single flat sheet fitted with a crank and motor to allow the membrane to be oscillated (or reciprocated) vertically at a low rate (20 RPM). The membrane was challenged with sludge samples from a local MBR installation treating petroleum industry effluent, the sludge having previously been demonstrated as having a high sludging propensity. Sludging was measured by direct visual observation of membrane surface occlusion by the agglomerated solids, with fouling being notionally represented by the rate of transmembrane pressure increase. Results demonstrated membrane reciprocation to have a more beneficial impact on sludging amelioration than on suppressing fouling. Compared with the stationary membrane, sludging was reduced by an average of 45% compared with only 13% for fouling suppression at the reference flux of 15 L·m−2·h−1 applied. The specific energy demand of the mechanical shear application was calculated as being around 0.0081 kWh·m−3, significantly lower than values reported from a recent pilot scale study on a reciprocated immersed hollow fibre MBR. Whilst results appear promising in terms of energy efficiency, it is likely that the mechanical complexity of applying membrane movement would limit the practical application to low flows, and a correspondingly small number of membrane modules.

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Effect of Ultrafiltration Operating Conditions for Separation of Ferulic Acid from Arabinoxylans in Corn Fibre Alkaline Extract

Sustainability ◽

10.3390/su13094682 ◽

2021 ◽

Vol 13 (9) ◽

pp. 4682

Author(s):

Rita Valério ◽

João G. Crespo ◽

Claudia F. Galinha ◽

Carla Brazinha

Keyword(s):

Ferulic Acid ◽

Operating Temperature ◽

Operating Conditions ◽

Separation Method ◽

Transmembrane Pressure ◽

Alkaline Extract ◽

Efficient Separation ◽

Crossflow Velocity ◽

Corn Fibre ◽

The Impact

Corn fibre, a co-product of the starch industry, is rich in compounds with high added value, such as ferulic acid and arabinoxylans, which are released during alkaline extraction. This work aims to optimise an efficient separation method for the recovery of these two compounds from a corn fibre alkaline extract, allowing an efficient valorisation of this co-product. Ultrafiltration was selected as separation method, due to its potential to fractionate these compounds. In order to minimise the loss of membrane permeance, due to mass transfer limitations caused by the high arabinoxylan viscosity, the impact of relevant ultrafiltration operating parameters (membrane molecular weight cut-off, fluid dynamics conditions, transmembrane pressure, and operating temperature) were evaluated. A Nadir UP 150 membrane was found to be an adequate choice, allowing for an efficient separation of ferulic acid from arabinoxylans, with null rejection of ferulic acid, a high estimated rejection of arabinoxylans 98.0% ± 1.7%, and the highest permeance of all tested membranes. A response surface methodology (RSM) was used to infer the effect of ultrafiltration conditions (crossflow velocity, transmembrane pressure and operating temperature) on the rejection of ferulic acid, retention of arabinoxylans (assessed through apparent viscosity of the retentate stream), and permeance. Through mathematical modelling it was possible to determine that the best conditions are the highest operating temperature and initial crossflow velocity tested (66 °C and 1.06 m.s−1, respectively), and the lowest transmembrane pressure tested (0.7 bar).

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