Filtration Process Parameters Research Articles

Start-up of biofilter for nitrification and effect of filtration rate on the ammonium removal efficiency in drinking water treatment on pilot plant

ABSTRACT Biological filtration is a process that can be used for ammonium removal from water. The removal of ammonium is based on the nitrification process. Nitrification depends on many factors, such as water quality and filtration process parameters. To investigate the influence of filtration rate on the nitrification efficiency, nitrifying biofilters were formed at the pilot plant in the industry for drinking water production from surface water. The new biological filters were started under optimal conditions for biofilm formation. After the biofilm formation, the influence of the filtration rate on nitrification was examined over 3 months (from November to January). The time required for the spontaneous growth of nitrifying bacteria on the new filters was around 70 days. The operating conditions at the start-up period were the continuous flow of water containing γ(NH4+) ≈ 1mg/L, dissolved oxygen in a concentration >9 mg/L, filtration rate <1 m/h, inlet water temperature >12 °C and pH from 7.8 to 8. After the complete formation of the nitrifying biofilm, the percentage of NH4+ removal was greater than 95% for all tested filtration rates, from 0.5 to 8.4 m/h, at γ(NH4+) from 1 to 2.5 mg/L and raw water temperature from 13 to 7°C.

Modeling of pharmaceutical filtration and continuous integrated crystallization-filtration processes

As continuous manufacturing is evolving in the pharmaceutical industry, continuous filtration has emerged as a bottleneck for connecting the crystallization of the active pharmaceutical ingredient with the formulation of the final drug product. This work aims the modeling of filtration to improve the understanding of the process, to support the development of continuous filtration methodologies, and to aid the integration of crystallization and filtration. The presented model utilizes the generalized form of Darcy’s law together with the calculation of the cake porosity and specific cake resistance based on the full crystal size distribution (CSD) of the slurry, without the need for experimental filtration data. The model is applied the first time for the dynamic simulation of an automated batch- type continuous filtration, which is also integrated with a population balance model of crystallization. The effect of the slurry properties (solid concentration, CSD) and the crystallization and filtration process parameters (crystallization temperature, flow rates, filter pressure difference, carousel rotation time) on the specific cake resistance, filtration time and residual moisture content are determined. It is concluded that continuous filtration facilitates the filtration of slurries with bad filterability through the modification of the rotation time and provides an opportunity to control the filtration when connected to a continuous crystallization. The simulation results show good agreement with real integrated continuous crystallization and filtration experiments of acetylsalicylic acid. The presented methodology could be used for both batch Nutsche filtration and continuous filtration to predict filterability and for optimization, risk analysis and control purposes.

Innovative Optical-Sensing Technology for the Online Fouling Characterization of Silicon Carbide Membranes during the Treatment of Oily Water.

The oil and gas industry generates a large volume of contaminated water (produced water) which must be processed to recover oil before discharge. Here, we evaluated the performance and fouling behavior of commercial ceramic silicon carbide membranes in the treatment of oily wastewaters. In this context, microfiltration and ultrafiltration ceramic membranes were used for the separation of oil during the treatment of tank dewatering produced water and oily model solutions, respectively. We also tested a new online oil-in-water sensor (OMD-32) based on the principle of light scattering for the continuous measurement of oil concentrations in order to optimize the main filtration process parameters that determine membrane performance: the transmembrane pressure and cross-flow velocity. Using the OMD-32 sensor, the oil content of the feed, concentrate and permeate streams was measured continuously and fell within the range 0.0–200 parts per million (ppm) with a resolution of 1.0 ppm. The ceramic membranes achieved an oil-recovery efficiency of up to 98% with less than 1.0 ppm residual oil in the permeate stream, meeting environmental regulations for discharge in most areas.

Retention of Acholeplasma laidlawii by Sterile Filtration Membranes: Effect of Cultivation Medium and Filtration Temperature.

ALCM: A. laidlawii culture medium; ASTM: American Society for Testing and Materials; ATCC: American Type Culture Collection; CFU/mL: colony-forming units per milliliter; DLS: Dynamic light scattering; LRV: Log reduction value; PES: Polyethersulfone; PFU/mL: Plaque-forming units per milliliter; PSD: Particle size distribution; PVP: Polyvinylpyrrolidone; SDS: Sodium dodecyl sulfate; SEM: Scanning electron microscopy; SLB: Saline lactose broth; TMP: Transmembrane pressure; TSB: Tryptic soy broth.

Removal of nickel and cadmium heavy metals using nanofiber membranes functionalized with (3-mercaptopropyl)trimethoxysilane (TMPTMS).

Functionalized nanofibrous membranes have been produced via electrospinning with a polymer solution of 19% (w/w) of nylon 66 prepared in a formic acid/chloroform mixture (75:25 v/v). The optimum parameters of electrospinning, like voltage, flow rate, tip and collector distances, were achieved and produced nanofiber membranes with a thickness of 287 nm. Then the nanofiber membranes were functionalized by (3-mercaptopropyl)trimethoxysilane (TMPTMS) at various amounts. Three different initial concentrations of metal ions and three different levels of pH were chosen. The effect of filtration process parameters such as the initial concentration of metal solution, pH of the solution, and the amount of functionalizer trimethoxysilane (TMPTMS) on the adsorption was studied. In surveying filtration process parameters, the results showed that metal ion rejection increased by increasing the pH of the solution and decreased by increasing the initial concentration of the effluent. By increasing the amount of functionalizer, removal efficiency increased. The results showed that the maximum efficiency of absorption of cadmium and nickel were 93.0 and 97.6%, respectively, and the filtering mechanism of the membrane is the blocking pores type. The adsorption data of cadmium and nickel ions fitted particularly well with the Freundlich isotherm.

Influência da massa molar de CMC no comportamento reológico e de filtração de suspensões argilosas

Resumo A carboximetilcelulose (CMC) é um polímero linear aniônico usado como agente viscosificante e redutor de filtrado e em fluidos de perfuração. A estrutura química e massa molar do polímero interferem nas interações complexas entre as cadeias poliméricas e os sólidos minerais presentes na suspensão. Desta forma, este trabalho teve como objetivo avaliar o comportamento reológico e de filtração de suspensões argilosas em função do aumento da concentração de aditivo polimérico com diferentes massas molares. Para tanto, foi utilizada uma amostra de argila bentonítica, comercialmente conhecida por Volclay, duas amostras de carboximetilcelulose com diferentes massas molares (CMC 1 (9,0 x 104 g/mol) e CMC 2 (2,5 x 105 g/mol)) e mesmo grau de substituição (DS = 0,7), e uma amostra de calcita. Foram determinadas as propriedades reológicas (viscosidades aparente e plástica, limite de escoamento e força gel) e de filtração (volume de filtrado, spurt loss ), espessura e permeabilidade do reboco, e poder de retenção) das suspensões argilosas. As propriedades reológicas e de filtração das suspensões argilosas preparadas com aditivos poliméricos são fortemente dependentes das interações CMC-argila e CMC-calcita e estas, por sua vez, são dependentes do grau de viscosidade e tamanho da cadeia do polímero.

A Risk-based Approach to Setting Sterile Filtration Bioburden Limits

Microbial control during the drug substance and drug product manufacturing process is critical for ensuring product quality and safety. For sterile biological drug products (finished dosage forms) typically manufactured by sterile filtration followed by aseptic processing, control of the microbial load at the sterile filtration step is an important component of the overall microbial control strategy. Both FDA and EMA regulatory guidelines stipulate that a maximum acceptable bioburden level, which is referred to as a pre-filtration bioburden level in this paper, should be stated at the point immediately prior to the sterile filtration step. The EMA guideline further states that a bioburden limit of no more than 10 colony-forming units (CFU) per 100 mL will be considered acceptable in most situations. The EMA guideline also states that a pre-filtration sample volume of less than 100 mL may be tested if justified. This paper introduces a risk-based method to establish pre-filtration bioburden acceptance levels and alternative test volumes. The relationship between bioburden risk, pre-filtration bioburden test limits, and sterile filtration process parameters, such as filtration volume, filter surface area, and microbial retention capacity of the sterilizing filter, was statistically determined. Taking into account the batch filtration volume, it is shown that pre-filtration bioburden test volumes and acceptance limits other than 10 CFU/100 mL may be justified, without compromise to sterility assurance. In the manufacturing of sterile medicinal products, good manufacturing practice requires that bioburden be monitored before the final sterilization filtration step. High bioburden increases the challenge to the sterilizing filter and may also lead to other quality issues. Therefore a pre-filtration bioburden limit should be established. This paper introduces a risk-based method to establish such limit which may be different from what is recommended in regulatory guidelines.

Scale-up analysis and critical issues of an experimental pilot plant for edible film production using agricultural waste processing

This study was developed to test a multifunctional experimental pilot plant with a reduced environmental impact that is able to process agricultural (fennel) and food production (liquid whey) waste. The pilot plant, using different thermal and filtration process parameters, is able to recover pectin and whey proteins in a single processing unit in order to produce edible films. An innovative feature of the proposed configuration is related to the possibility of coupling different types of waste treatment, obtaining a final product with a higher economical value, combining the two processing lines. Although an edible film production procedure based on pectin extracted from fennel matrix and whey proteins has already been published in literature, the scale-up process highlighted several critical issues, in particular related to the fennel matrix. Nonetheless, the pilot plant configuration allowed an edible film to be produced that is suitable for use as a direct coating to improve the shelf-life of food products.

Scale-up analysis and critical issues of an experimental pilot plant for edible film production using agricultural waste processing

This study was developed to test a multifunctional experimental pilot plant with a reduced environmental impact that is able to process agricultural (fennel) and food production (liquid whey) waste. The pilot plant, using different thermal and filtration process parameters, is able to recover pectin and whey proteins in a single processing unit in order to produce edible films. An innovative feature of the proposed configuration is related to the possibility of coupling different types of waste treatment, obtaining a final product with a higher economical value, combining the two processing lines. Although an edible film production procedure based on pectin extracted from fennel matrix and whey proteins has already been published in literature, the scale-up process highlighted several critical issues, in particular related to the fennel matrix. Nonetheless, the pilot plant configuration allowed an edible film to be produced that is suitable for use as a direct coating to improve the shelf-life of food products.

Preparation of sulfonated poly(ethylene terephthalate) submicron fibrous membranes for removal of basic dyes

AbstractIn this investigation, a nanofibrous sulfonated poly(ethylene terephthalate) (SPET) membrane was prepared by electrospinning of the SPET solution in trifluoroaceticacid (TFA)/dichloromethane (DCM) mixture. The produced nanofibers had diameter ranging from 300 nm to 1 μm. The performance of this membrane's separation process was evaluated under different operating conditions. The influence of the electrospinning and filtration process parameters, such as concentration, applied voltage, deposition time, operating pressure, and filtration time on rejection of C.I. Basic Blue 3 were studied. The dead‐end recirculation ultrafiltration set‐up was employed. Under optimum conditions (concentration of 20% (w/v) of SPET, applied voltage of 20 kV and deposition time of 3 h) the removal of the aforementioned dye was 98%. Operating pressure has posed a significant influence on the membrane's separation performance, whereas the operating time had some effect on the separation performance. Two equilibrium adsorption isotherms: Langmuir and Freundlich were fitted to the dyes' equilibrium sorption data on SPET membrane at different feed concentrations. The Freundlich isotherm was found to well represent the measured adsorption data based on the higher coefficient of determination (r2). © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Use of Hydrogenophaga pseudoflava penetration to quantitatively assess the impact of filtration parameters for 0.2-micrometer-pore-size filters.

Filters rated as having a 0.2-microm pore size (0.2-microm-rated filters) are used in laboratory and manufacturing settings for diverse applications of bacterial and particle removal from process fluids, analytical test articles, and gasses. Using Hydrogenophaga pseudoflava, a diminutive bacterium with an unusual geometry (i.e., it is very thin), we evaluated passage through 0.2-microm-rated filters and the impact of filtration process parameters and bacterial challenge density. We show that consistent H. pseudoflava passage occurs through 0.2-microm-rated filters. This is in contrast to an absence of significant passage of nutritionally challenged bacteria that are of similar size (i.e., hydrodynamic diameter) but dissimilar geometry.

Expression behaviour of fine particle suspensions and the consolidated cake strength

The high-level expression of suspensions up to 50 bar is concerned with the recovery of finest particles, e.g. submicron particles. A so-called Press-Shear-Cell was designed, constructed and tested to measure the most important filtration process parameters. In a first filtration stage, a compressible filter cake builds up from a fine particle suspension. The following cake consolidation is applied to reduce the liquid amount in the small pores of the particle packing. To describe the two-stage expression process of fine sludge, a new dynamic model is introduced. In contrast to the common Tiller–Shirato model, which assumes constant average material properties of particle pressure p s, packing density ε s and permeability k inside the cake during constant pressure expression, the new dynamic expression model considers the time and local variation of these material properties. Furthermore, the wall friction resistance is taken into account with the wall friction angle ϕ W and the lateral pressure ratio λ of the cake. The pressure-dependent constitutive functions of kaolin and titanium dioxide filter cakes are shown. Yield loci in a water saturated particle packing were in situ measured with comparatively high normal loads of 100–1000 kPa.

Methods of calculating and optimizing filtration process parameters when the suspension is fed onto the filter by a centrifugal pump

Methods of calculating and optimizing filtration process parameters when the suspension is fed onto the filter by a centrifugal pump