Depth Filtration Research Articles

Propped fracture conductivity in shale oil reservoirs: Prediction model and influencing factors

Hydraulic fracturing is the main measure for stimulation of shale oil reservoirs, but the high content of clay minerals, well-developed bedding, and low mechanical strength of shale rock often result in a strong stress sensitivity of propped fractures associated with shale hydration expansion and proppant embedment in fracture wall. Especially under conditions of low sand laying concentration, the fracture conductivity can be greatly reduced. In this paper, a comprehensive prediction model of propped fracture conductivity in shale oil reservoirs was established, which considers the damage mechanisms of proppant compression, embedment, crushing, and shale hydration and expansion. The sensitivity analysis of factors affecting the fracture conductivity indicates that the proppant particle size, involved damage mechanisms, Kozeny-Carman coefficient, proppant layer number, and proppant density are the main factors to determine the fracture width and permeability and further affect the fracture conductivity. Most of the rest factors are related to the specific fracture damage mechanisms. The influence of shale hydration expansion is larger than that of proppant particle compression which is further larger than that of proppant crushing. In a real hydraulic fracture, the fracture width decreases from fracture heel to toe, caused by the non-uniform laying concentration of proppant. For the fracture near the wellbore usually with a large sand laying concentration, the influences of different factors are ranked as follows: proppant particle size > elastic modulus of proppant > fluid pressure > hydration expansion coefficient > filtration depth. For the front of the fracture with a low sand laying concentration, it is easy to close, which is sensitive to all the above factors. To achieve a high and stable fracture conductivity, the anti-swelling agent should be used to prevent shale hydration expansion. Large-size proppants with high elastic modulus should be selected to prop up the front of the fracture, and the decline of bottom-hole flow pressure should be controlled during the depressurized production process. The obtained results have a certain guiding significance for understanding the factors of shale fracture conductivity and the optimization of fracture parameters.

Streamlined Clarification and Capture Process for Monoclonal Antibodies Using Fluidized Bed Centrifugation and Multi-Column Chromatography With Membrane Adsorbers.

Harmonizing unit operations in the downstream process of monoclonal antibodies (mAbs) has a high potential to overcome throughput limitations and reduce manufacturing costs. This study proposes a streamlined clarification and capture (S-CC) process concept for the continuous processing of cell broth harvested from a connected bioreactor. The process was realized with a fluidized bed centrifuge connected to depth and sterile filters, a surge tank, and a multi-column chromatography (MCC) unit. The MCC unit was operated in the rapid cycling simulated moving bed (RC-BioSMB) mode with five convective diffusive membrane adsorbers (MAs). A control strategy and the surge tank were used to adjust the loading flow rate of the MCC unit. The mAb was recovered with a total process yield of 90%, with high removal of the process-related impurities HCP (2.1 LRV) and DNA (2.9 LRV). Moreover, the S-CC process productivity of 4.2 g h- 1 was up to 5.3 times higher than for comparable, hypothetical batch MA processes. In addition, the buffer consumption of the capture step could be reduced from 2.0 L g- 1 in batch mode to 1.2 L g- 1 in the RC-BioSMB mode. These results demonstrate the high potential of streamlined interconnected unit operations to improve the overall mAb downstream process performance.

From Tradition to Innovation: An In-Depth Review of Manganese Removal Techniques in Water Treatment

Contamination of water is currently one of the alarming issues all around the planet. Water that is contaminated with manganese (Mn) could potentially give rise to functional and aesthetic complications. Removal of manganese is critical and often has substantial implications for the layout of treatment trains. Precipitation, ion exchange, depth filtration, oxidation, adsorption, biosorption, and biological methods are the traditional chemical, physical, and biological processes for removing Mn (II) from contaminated water. All these treatment processes have some advantages and disadvantages and are based on which the implementation of any process varies. In recent years, the use of biofiltration to eliminate manganese (Mn) from water has grown owing to the progress made in molecular techniques for studying microorganisms found in biological Mn elimination systems. This study aims to contribute to the existing research on Mn occurrence and highlight the historical and current removal strategies used in drinking water treatment. The main objective is to assist future researchers in developing more efficient technologies and clarify the subject matter.

Evaluation of Effluent Quality Trends Before and After Filtration Through the Composite Filter from Shirere Wastewater Treatment Plant to River Isiukhu in Kakamega County, Kenya

The current stabilization ponds as wastewater treatment practices in urban areas have proven insufficient with continued discharge of untreated wastes into water bodies. Their challenge comes from inappropriate system selection and maintenance, improper design, construction mistakes, physical damage and hydraulic overload. Appropriate infrastructural technologies for waste removal that can be adopted in the drainage channels of effluents into water bodies are scarce. This study incorporates a reactor based composite filter of pumice and sand as an innovative approach for removing residual waste in effluents discharged from Shirere Wastewater Treatment Plant into River Isiukhu, Kakamega Municipality. The objective of the study was to evaluate the trend of effluent quality from Shirere wastewater treatment plant upto river Isiukhu before and after installation of composite granular filter. Effluents, drinking water from Shirere WWTP, Shikoye stream, River Isiukhu and protected spring along Shikoye stream, were collected using presterilized water sampling containers for microbial quality analysis at MMUST and KACWASCO laboratories. The measurements were carried out using UV-VIS spectrophotometer at 752 nanometer wavelengths. Research design was experimental. The average reduction of COD in the mid-season of June to August was 42.2 ±4.6%, being the highest. Concomitantly, the BOD removal by the filter in the season of June to August was19.6±7% and 15.6 ±3.5% for September to November. The average rate of TSS removal in June to August was 19.3±4.5% followed by 16.6±3.8% in September to November and 11.6±7% in March to May. The average rate of Nitrate removal in June to August was 41.8±7.6% followed by 30.0±2.2% for March to May and 25±8.6% for September to November. Phosphates had an average rate of removal in June to August at 31.9±2.7% followed by 20.6±4.8% for September to November and 20.0 ±4.3% for March to May. Specifically, for the first season of March – May 2021 at 200 mm filtration depth were carried out at effluent flow rate of 0.0032 and volume, 0.234 Concentrations of most parameters were above NEMA standards, like COD was 322mg/l yet maximum should be 100 mg/l. Therefore, it was concluded that silica pumice composite filter performance was achieved by big variations in the concentrations of COD, BOD, TSS, Phosphates and Nitrates at Shirere WWTP after filtration which was attributed to effective removing capacity. The effluent concentrations from sampling sites S1-S3 and S5-S7 were found to be above the NEEMA standards implying the high risk of using Isiukhu water and catchment area. Thus, this study recommended that, the composite filter reduced concentrations of all the parameters (COD, BOD, TSS, PO3, NO3) significantly from Shirere WWTP along Shikoye stream up to the confluence of river Isiukhu. Most of the parameters after filtration were ranging within the required standards of NEMA. The requisite measure of adopting new technology of composite filtration should be sustained.

Composite Membranes of Polyhydroxyalkanoate and Cellulose for Depth Filtration

Composite Membranes of Polyhydroxyalkanoate and Cellulose for Depth Filtration

Scalable Purification, Storage, and Release of Plant-Derived Nanovesicles for Local Therapy Using Nanostructured All-Cellulose Composite Membranes.

Plant-derived nanovesicles such as bilberries nanovesicles (BNVs) show immense promise as next-generation biotherapeutics and functional food ingredients; however, their isolation, purification, and storage on a large scale remain a challenge. In this study, biocompatible and nanostructured composite all-cellulose membranes are introduced as a scalable and straightforward approach to the isolation of BNV. The membranes consisting of a cellulose acetate matrix infused with anionic or cationic nanocelluloses promoted selective capture of BNVs through electrostatic and size-exclusion-mediated depth filtration. Furthermore, the surface of the composite membrane acted as a storage matrix for BNVs, ensuring their prolonged stability at 4 °C. The BNVs stored in the membrane could be promptly released through elution assisted by low-pressure vacuum filtration or diffusion in liquid media. The morphology, bioactivity, and stability of the extracted BNVs were preserved, and the release rate of BNVs in different cell cultures could be regulated, facilitating their use for local therapy. Consequently, this approach paves the way for the scalable production, purification, and storage of nanovesicles and advances their use in biotherapeutics and functional foods.

Pilot-scale evaluation of a dynamic body-feed filtration system for primary clarification of snake antivenoms produced by the caprylic acid method

The performance of dynamic body-feed filtration (DBF) in the removal of bulky solids produced during the manufacturing of snake antivenoms using the caprylic acid method was evaluated. For this purpose, diatomites with different filterability properties were compared in a bench-scale study to assess their effectiveness in removing the precipitated material formed after the addition of caprylic acid to equine hyperimmune plasma. C1000 diatomite at a concentration of 90 g/L of precipitated plasma showed the best performance. Then, the process was scaled up to three batches of 50 L of hyperimmune horse plasma. At this pilot scale, 108 ± 4% of the immunoglobulins present following plasma precipitation were recovered after DBF. The antivenoms generated using this procedure met quality specifications. When compared to open filtration systems commonly used at an industrial scale by many antivenom manufacturers, DBF has a similar yield and produces filtrates with comparable physicochemical characteristics. However, DBF ensures the microbiological quality of the primary clarification in a way that open systems cannot. This is because: 1) DBF is performed in a single-use closed device of depth filters which prevents microbial contamination, and 2) DBF removes bulky material in few minutes instead of the more than 24 h needed by open filtration systems, thus reducing the risk of contamination. It was concluded that DBF is a cost-effective, easily validated, and GMP-compliant alternative for primary clarification following caprylic acid precipitation of plasma in snake antivenom production.

Evaluation of the critical factors that influence the performance of a Geo-Fabric based Bio-Filter (GFBF)

Bio-filters are high-rate aerobic biological systems with porous support media for biofilm formation and filtration of suspended solids. The support media and its ability to remove contaminants decides the performance of bio-filter. Geo-fabrics, with properties like permeability and large surface area are capable of maintaining good biomass which in turn can absorb and adsorb substrate from influent to make them an attractive media for bio-filter systems. This paper investigates the critical factors that determine the performance of a Geo-Fabric based Bio-Filter (GFBF). Experiments conducted using geo-fabric of varying GSM were analyzed and optimized using Response Surface Methodology. The results indicated that by varying process variables like HRT, C:N ratio, rate of aeration and depth of filter, the geo-fabric with 500 GSM value showed improved performance compared to geo-fabric of 300 GSM and 400 GSM. The final experimental run conducted on GFBF with geo-fabric of 500 GSM at optimized value of process variables, observed 91 %, 98 %, 88 %, 90 % and 71 % removal of COD, BOD, NH3-N, turbidity and TDS respectively. GFBF are suitable for treatment plants where the amount of wastewater generated is relatively small and a complete treatment can be accomplished in one unit.

Optimization of surface filtration to enhance wafer uniformity by removing large particle in ceria slurry

Owing to the limitations of scaling down, the development of complex structures for chip design is progressing in the semiconductor industry. As a result, the chemical mechanical polishing (CMP) process has become essential for the precise control of micro-level steps and for maintaining surface uniformity between layers during the stacking process. Structural management and improved performance of the consumables used in CMP processes are required. In particular, controlling the abrasive particles in the slurry that directly contact the wafer surface is crucial. Large particles within the slurry can occur scratches and cause non-uniformity in the polishing process, thus the particle size distribution of the slurry must be regulated. In this study, two types of filtration systems were constructed to determine the optimal conditions for CMP of ceria slurry. Depth filtration effectively removes particles through a cake layer formation mechanism but has limitations in achieving a consistent pore size within the fiber layer. Consequently, separation efficiency for particle sizes is relatively low. In contrast, surface filtration consisting of a single membrane demonstrates a consistent correlation between pore size and the size of the filtered particles, resulting in high particle removal efficiency. The pore size capable of removing large particles without active particle loss was 200 nm. After evaluating slurry productivity and filter-induced agglomeration, 0.8 L per minute (LPM) was identified as the optimal flow rate. Additionally, after filtration at 0.8 LPM, the maximum reduction in removal rates was relatively small at 272.54 Å/min due to decreased edge removal rates. However, by removing large particles to implement a monodisperse state, an improvement in uniformity of 17.11 % was achieved. Therefore, the CMP performance can be enhanced using surface filtration to control the particle size distribution (PSD).

Depth filtration of dredged sediments via reduced iron driving persulfate sodium activation: Perspectives from technical viability, potential mechanism, and prospect assessment

The existing single-use conditioning agents for dredged sediments (DS) treatment were confronted with problems such as high cost, insufficient efficiency, or potential toxicity. The study, for the first time, utilized a heterogeneous process of reduced iron (RI)/Persulfate sodium (PS) to deeply filter DS and further uncovered the potential mechanism as well as raised the application prospect. The results showed that after 120 mg/g TSS RI with 40 mg/g TSS PS treatment, the water content (WC) of DS dropped from 75.4% (Blank) to 41.6%, which is obviously lower than that of traditional flocculant-treated DS reported. Mechanistic probe indicated that the strengthened filterability of DS is likely evoked by the sulfate radical (SO4●-)/hydroxyl radical (•OH) with the ferrous/ferric substances generated from RI/PS process. SO4●-/•OH damaged extracellular polymeric substances (EPS) along with their major ingredients and possibly disturbed cellulate physiology of DS, which further promoted the dissociation/liberation of bound-water and strengthened a trend toward fluidization but declined the hydrophilicity and stickiness of DS. Moreover, SO4●-/•OH may evoke the proteins conformation to unfold the hydrophobic spots, promoting the escape of untied water also. By extruding the electric-double layers and lowing the negative charge, Ferrous and/or ferric substances promotes the re-aggregation of disrupted DS particles, which potentially leads to the formation of dense & stable flocs through interaction of ferric substances with carboxyl and hydroxyl functional groups in DS, thus facilitating bound-water removal. The findings here not only deepen our understandings upon mechanisms of heterogeneous AOPs conditioning DS filterability but also offer a promising approach for DS treatment in the fields of solid waste management and water environment remediation.

Simulative analysis of carrier suppressed return to zero based symmetrical compensated optical link

Abstract Optical communication systems provide high data rates to fulfil users’ demands. In addition, the modulation format is essential to the system’s transmission quality and spectral efficiency. Furthermore, the effects of chromatic dispersion, which impair the performance and quality of transmitted signals, are mitigated using dispersion compensation techniques. In optical communication systems, dispersion compensation techniques are essential for preserving signal quality, increasing transmission distances, improving system performance, and offering network designers flexibility. These methods seek to improve signal quality and enable transmission at longer distances by reducing or eliminating the distortion brought on by dispersion. This paper uses a symmetrical compensation technique to analyze the performance of the CSRZ modulation format-based optical communication system. The research is conducted within a communication range of 150–350 km. The system is evaluated in terms of input power, filter order, and filter depth. The results indicate that the proposed system performed better at an input power of 4 dBm using a third-order filter and 60 dB filter depth.

Single-use chromatographic clarification to eliminate endonuclease treatment in production of recombinant adeno-associated viral vectors

In current manufacturing processes for recombinant adeno-associated viral vectors (rAAV), endonuclease treatment is used prior to depth filtration to break down host cell DNA that is released from cells post-lysis. Without this treatment, traditional depth filters exhibit negligible clearance of host cell DNA, a key process-related impurity. In this work, we evaluate single-use chromatographic clarification using Harvest RCTM filters (3 M) to process rAAV8 and rAAV9 HEK293 cell culture lysate with and without endonuclease pretreatment. We demonstrate endonuclease-free clarification for both serotypes with yield >90 % and up to 3 log reduction of host cell DNA, from >104 ng/mL to <50 ng/mL, matching or exceeding the filtrate quality in traditional depth filtration with 100 U/mL of endonuclease added during lysis. The addition of 100 mM of salt in the harvest buffer is also shown to improve filtration throughput, prevent filter clogging, and limit rAVV binding to the filter device. Finally, a mechanistic cake-fiber fouling model is shown to be a good representation of the Harvest RCTM filtration mechanism. The endonuclease-free clarification approach enables cost savings of USD 100,000 per 500 L batch, equivalent to the cost of cGMP-grade endonuclease at this scale. The benefits of endonuclease-free clarification further include easier raw material sourcing as well as eliminating the need for a residual endonuclease assay in rAAV manufacturing processes.

Design and optimization of gradient fibrous media using the method of moments

The goal of this work is to optimize the deposition mass distribution of polydisperse particles inside the fibrous media by modifying the distribution of the fiber packing density across filter depth. Two types of gradient fibrous media with linear and exponential fiber packing density distribution along the flow direction were derived. The method of moments was employed to study the transport and deposition characteristics of polydisperse aerosol particles inside the fibrous media. The reliability of the calculated results by the method of moments was confirmed by the numerical simulations based on the discrete phase model (DPM). Results indicate that the gradient fibrous media allows more particles to transport and deposit into the interior of the fibrous media, which improves the uniformity of particle deposition distribution across filter depth. There exists an optimal fiber packing density distribution ratio for the gradient fibrous media where the non-uniformity of deposition mass distribution of polydisperse particles across filter depth is minimized. In this way, uniform deposition distribution along the flow direction can be generally achieved by optimizing the fiber packing density distribution, which will contribute to the optimal design of microstructures for the fibrous filter.

Stability of the walls of trenches filled with polyacrylamide support fluids

The development of the underground space of cities is increasingly carried out with maximum approximation to the foundations of the surrounding buildings. To ensure the safety of buildings in the surrounding area, an assessment of the impact of accounting for all stages of construction work is required. The problem of ensuring the stability of the trench walls at the time of the wall in the ground installation is considered, provided that the trench is filled with polyacrylamide drilling mud, which is increasingly used as an alternative to traditional clay slurry. The effect of the filtration depth of the solution on the stability of the trench wall to the dynamic impacts is shown. Based on laboratory experiments on unsteady filtration of solutions, a method for assessing the stability of trench walls in sandy soils is proposed.

NSVDNet: Normalized Spatial-Variant Diffusion Network for Robust Image-Guided Depth Completion

Depth images captured by low-cost three-dimensional (3D) cameras are subject to low spatial density, requiring depth completion to improve 3D imaging quality. Image-guided depth completion aims at predicting dense depth images from extremely sparse depth measurements captured by depth sensors with the guidance of aligned Red–Green–Blue (RGB) images. Recent approaches have achieved a remarkable improvement, but the performance will degrade severely due to the corruption in input sparse depth. To enhance robustness to input corruption, we propose a novel depth completion scheme based on a normalized spatial-variant diffusion network incorporating measurement uncertainty, which introduces the following contributions. First, we design a normalized spatial-variant diffusion (NSVD) scheme to apply spatially varying filters iteratively on the sparse depth conditioned on its certainty measure for excluding depth corruption in the diffusion. In addition, we integrate the NSVD module into the network design to enable end-to-end training of filter kernels and depth reliability, which further improves the structural detail preservation via the guidance of RGB semantic features. Furthermore, we apply the NSVD module hierarchically at multiple scales, which ensures global smoothness while preserving visually salient details. The experimental results validate the advantages of the proposed network over existing approaches with enhanced performance and noise robustness for depth completion in real-use scenarios.

Combining descriptive and predictive modeling to systematically design depth filtration-based harvest processes for biologics.

Advances in upstream production of biologics-particularly intensified fed-batch processes beyond 10% cell solids-have severely strained harvest operations, especially depth filtration. Bioreactors containing high amounts of cell debris (more than 40% particles <10 µm in diameter) are increasingly common and drive the need for more robust depth filtration processes, while accelerated timelines emphasize the need for predictive tools to accelerate development. Both needs are constrained by the current limited mechanistic understanding of the harvest filter-feedstream system. Historically, process development relied on screening scale-down depth filter devices and conditions to define throughput before fouling, indicated by increasing differential pressure and/or particle breakthrough (measured via turbidity). This approach is straightforward, but resource-intensive, and its results are inherently limited by the variability of the feedstream. Semi-empirical models have been developed from first principles to describe various mechanisms of filter fouling, that is, pore constriction, pore blocking, and/or surface deposit. Fitting these models to experimental data can assist in identifying the dominant fouling mechanism. Still, this approach sees limited application to guide process development, as it is descriptive, not predictive. To address this gap, we developed a hybrid modeling approach. Leveraging historical bench scale filtration process data, we built a partial least squares regression model to predict particle breakthrough from filter and feedstream attributes, and leveraged the model to demonstrate prediction of filter performance a priori. The fouling models are used to interpret and provide physical meaning to these computational models. This hybrid approach-combining the mechanistic insights of fouling models and the predictive capability of computational models-was used to establish a robust platform strategy for depth filtration of Chinese hamster ovary cell cultures. As new data continues to teach the computational models, in silico tools will become an essential part of harvest process development by enabling prospective experimental design, reducing total experimental load, and accelerating development under strict timelines.

In-line image analysis of particulate processes with deep learning: Optimizing training data generation via copy-paste augmentation

Monitoring particle properties directly in the process using in-situ microscopes can provide valuable input for control loops, improve process understanding, and facilitate process optimization. However, obtaining reliable information from these images is still challenging, particularly for higher solids concentrations or agglomerating systems. Recent studies have successfully applied deep learning models to extract particle characteristics from in-situ image data. Despite these advances, the problem of generating training data has not been properly addressed. Manual annotation is time-consuming and prone to bias due to high particle counts, particle overlap, and out-of-focus objects. This paper introduces a new approach to generating training data for segmentation models by combining conventional segmentation methods with copy-paste augmentation. A case study was conducted in which depth filtration experiments were performed using irregularly shaped alumina particles. An instance segmentation model trained on data created with the proposed approach successfully detected and characterized particles, even at high solids concentrations.

Detachment of particulate structures from a fiber array due to stretching and simultaneous gas flow

The main cause of high pressure drop and increased energy consumption in a filtration process is the clogging of particulate material in the upstream layers of a depth filter. To alleviate this issue, stress can be introduced into the particulate structure through stretching, which promotes rearrangement and detachment of particle structures, allowing for transfer of some of the clogged particulate material from the upstream layers to downstream void regions. This study aims to extend previous findings from experiments with single fibers to the level of an array. The goal is to analyze the introduction of a multiple stress state by performing stretching experiments with a particle-structure on a fiber array.The stretching tests investigate the influence of different process parameters such as stretching velocity and air flow velocity during stretching on the rearrangement and detachment behavior of a separated particle structures from the fiber array. Rearrangement and detachment of the particle structure are a direct consequences of the stress induced by stretching. The experiments showed a significant increase in relative free projection area of fiber interspaces (RFPI) of up to 160% and thus a large-scale removal of particle material from the fiber interspaces when the flow velocity was increased from 0.05 m/s to 0.8 m/s. Surprisingly, the radial rearrangement of the compact particle structures during stretching resulted in a clogging and blockage of the interfiber spaces (negative RFPI in the range of minimum −54% after the first stretching cycle) and not in a total release of the interfiber spaces. The size of the particle structures in the experiments decreased by about 331 μm with the number of stretching cycles, indirectly confirming the presence of residual structures. Preliminary experiments also confirmed an increased influence on the rearrangement and detachment (removed pariticulater material of about 30%) of particle structures by further increasing the fiber distance of 27 μm and thus introducing a biaxial stretching into the particle structure.

Intensified production of recombinant vesicular stomatitis virus-based vectors by tangential flow depth filtration

Intensified production of recombinant vesicular stomatitis virus-based vectors by tangential flow depth filtration

Efficacy of gonadal shielding in dose reduction for female pelvic radiography.

This study aimed to evaluate the dose reduction using gonad shielding (GS) during pelvic imaging. Three types of pelvic images (radiography, magnetic resonance and computed tomography) were fused to elucidate the three-dimensional relationship between the position of ovaries and GS. To estimate the dose received by the ovaries, the off-axis dose at any given depth was measured under two different imaging conditions using thermoluminescence dosemeters and a polymethyl methacrylate phantom. The mean ovarian depth was 8.4cm. The mean estimated ovarian dose without an additional filter was 0.36mGy without GS and 0.14mGy with GS. The mean estimated ovarian dose with an additional filter was 0.24mGy without GS and 0.10mGy with GS. The efficacy of ovarian dose reduction should be evaluated based on the achieved ovarian dose, considering the ovarian depth and use of additional filtration, rather than the ovarian protection rate of GS.