Clarification System Research Articles

Design and Application of Prefiltering Seawater Clarification System for Small Seawater Desalination System in Tropical Islands

Zheng, L.; Fan, K.; Luo, Y.; Shao, Q.; Hu, H., and Wu, X., 2020. Design and application of prefiltering seawater clarification system for small seawater desalination system in tropical islands. In: Hu, C. and Cai, M. (eds.), Geo-informatics and Oceanography. Journal of Coastal Research, Special Issue No. 105, pp. 233–236. Coconut Creek (Florida), ISSN 0749-0208.Owing to the characteristics of the marine environment, seawater desalination systems of offshore islands in tropical areas will absorb more impurities, which often results in premature aging of the reverse osmosis membrane of the seawater filtering desalination system, such as air scrubbing tank and ultrafiltration equipment. This article proposes a design scheme of a prefiltering seawater clarification system. Experiments show that the filtering system can effectively reduce the operating burden of follow-up equipment and improve the efficiency of desalination equipment. It is suitable for popularizing this technology in similar islands.

A Mini-Review on Cell Cycle Regulation of Coronavirus Infection.

Coronaviruses are widespread in nature and infect humans, mammals and poultry. They cause harm to humans and animals. Virus-mediated cell cycle arrest is an essential strategy for viral survival and proliferation in the host cells. A clarification system of the mechanisms of virus-induced cell cycle arrest is highly desirable to promote the development of antiviral therapies. In this review, molecular mechanisms of coronavirus-induced cell cycle arrest were systematically summarized. Moreover, the common features of coronavirus-mediated cell cycle arrest were discussed. This review will provide a theoretical basis for further studies on the infection mechanisms and prevention of coronaviruses.

Natural agents as auxiliaries in water clarification: literature review and experimental evaluation

The increasing demand for water resources (primarily for human consumption and industrial and agricultural activity) is driven by socio-economic development, and population growth. Recent research has been focusing on alternative coagulants based on natural elements, as opposed to the commonly used iron and aluminum salts, for use in water and wastewater treatment processes. In this context, a thorough literature review on alternative coagulants and their application to water treatment processes has been conducted in this work. In addition, three experiments have been conducted with a widely used natural organic coagulant (Moringa oleifera). The alternative clarification system used is the helically coiled tube flocculator (HCTF), with high turbidity removal efficiency and low processing times. A comparative analysis of the turbidity reduction over time was performed with samples collected after 600, 900, 1200, 1500, 1800, 2100, 2400, and 2700 s from the hydraulic circuit. The process efficiency using the proposed alternative coagulant reached 95.3% (after 1800 s). The turbidity removal efficiency remained almost constant after 1800 s, with variations below 1%. These results prove that natural alternative agents can be powerful tools in the water treatment process, with efficiency values exceeding those obtained using chemicals (e.g., aluminum sulphate) as coagulant/ flocculant agents.

Effect of Clarification System on the Conservation of Virgin Olive Oil during Its Storage

AbstractThe results obtained in this work explain how clarification systems can affect the conservation of virgin olive oils (VOOs) during the storage step. The evolution of the quality and sensory properties during the storage of VOOs clarified by different systems, vertical centrifugal separator (VCS) with minimal water addition and conical bottom settling tank (CBST), is studied at industrial scale for two different crop years. In general, VCS oils show a slight higher moisture and solid impurities content at the end of the storage step due to a higher emulsion grade (because of the emulsion generated) caused by the rotating movement of this clarification system. For the studied clarification systems, no remarkable differences are observed between the oils during their storage for quality indexes. However, these systems show differences regarding oil sensory properties. The VOOs clarified by VCS are characterized by a higher presence of phenol components, higher positive sensory attributes intensity, and higher lipoxygenase (LOX) aldehydes content during their storage. VOOs from CBST show lower phenol content, a higher “non‐LOX” volatiles content, and the presence of sensory defects during storage.Practical Applications: The results obtained in this work are very important in order to provide specific recommendations and scientific support based on objective data to improve VOO quality. As described in this study, the VCS with a minimal water addition can be a better option to produce VOO of improved quality. This clarification system is an efficient and quick operation that reduces the contact between oil and the remaining water and impurities during the storage step. The minimal water addition used in this clarification system allows obtaining VOOs with higher phenol content and positive sensory notes. This leads to prolong VOO shelf‐life and conservation during the storage stage, due to preservation of the quality indexes and minor components with antioxidant activity. Besides, this clarification system reduces the water consumption during oil clarification and generates a lower wastewater volume regarding conventional vertical centrifugation, and therefore can be considered more environmentally friendly.

Robustness analysis of technological units for drinking water clarification: Normal and emergency operating conditions

The primary goal of a water supply system is the protection of human health by providing microbiologically and chemically safe drinking water. Significant changes in water quality require sufficiently robust systems for water preparation, performances of which are unaffected by present variations and changing operational conditions. Water turbidity is an important parameter for the water filtration control and efficiency of disinfection. The efficiency of turbidity removal in the drinking water treatment plant ?Vodovod? in Banjaluka under normal and emergency operating conditions was examined in this paper. At normal conditions the maximal detected value was 25 NTU while at emergency operating conditions it was above 240 NTU. Robustness evaluation of the water clarification system was performed separately for periods of normal and emergency operating conditions (during and after emptying the accumulation). The robustness index was calculated based on a more stringent target turbidity value (0.5 NTU) than that specified by the current legislation, which represents a new criterion in the risk analysis in the existing practice. Data processing results indicate high operational stability of technological units under normal conditions. The filtered water quality was below the target value during most of the time of filter operation in all cycles. The recorded turbidity value was ? 0.3 NTU for 92.9 % of filtered water samples. Analysis of the water turbidity data has shown that 17% of all taken measurements under emergency operating conditions (336 samples) had higher turbidity than the target value (0.5 NTU). Large variations in raw water turbidity over short periods of times during the emergency operating conditions, present a problem for prompt response in the drinking water plant. Calculated robustness index values point to inadequate efficiency of the water clarification process in a certain number of filter operating cycles. We have found a significant impact of the plant operating conditions on the filtered water turbidity under emergency conditions, such as suboptimal coagulation and flocculation conditions as well as the nature of suspended and colloid particles inducing turbidity and insufficient particle interactions with the coagulant. Along with the negative influence on water turbidity, excessive coagulant dosage leads to increased concentrations of residual aluminum in filtered water. Optimization of emergency working conditions could be performed based on adequate monitoring of water sources, which would further decrease potential risks of pathogen appearance in drinking water.

学校トイレの改修に伴う非常時対応節水トイレシステムに関する研究 第1報 システムの課題点と単独器具排水の性能評価

学校トイレの改修に伴う非常時対応節水トイレシステムに関する研究 第1報 システムの課題点と単独器具排水の性能評価

Novel approaches for predicting efficiency in helically coiled tube flocculators using regression models and artificial neural networks

AbstractIn this paper, prediction models for turbidity removal efficiency (TRE) in helically coiled tube flocculators (HCTFs) are presented. The TRE was determined by physically modelling a compact, high‐performance and low detention time clarification system composed of a HCTF coupled to a decantation system. The values of hydrodynamic representative parameters of the flow were determined by CFD modelling. Eighty‐four different configurations of HCTFs were evaluated. Multiple linear/non‐linear regression and artificial neural network analyses were performed. A determination coefficient (R2) of 0.81 was obtained using multiple linear regression with the geometric and hydraulic parameters. In this model, the root mean squared error (RMSE) was 3.29%. Adding hydrodynamic parameters and using the artificial neural networks, R2 reaches 0.96 and RMSE decay to 1.58%. These results indicate that the use of effective efficiency prediction models can be helpful in the design of new flocculation units and for the improvement of existing ones.

Comparison study of the effect modeling of flow parameters on the membrane clarification efficiency for pomegranate juice

In recent years, several studies have indicated that modeling techniques based on artificial intelligence can be used for efficient prediction of food industry-related variables. In this study, machine learning methods were used to predict the permeate flux of pomegranate juice in a membrane clarification system based on membrane material, pore size, pressure, flow rate, and processing time. The experimental data were modeled using curve fitting, fuzzy inference system (FIS), artificial neural networks (ANN), and adaptive neuro-fuzzy inference system (ANFIS). Results showed that the permeate flux is a function of time and a power equation can predict the permeate flux with MSE of 0.0136. FIS, ANN and ANFIS models resulted in MSEs equal to 0.0495, 0.0145, and 0.0045 for permeate flux prediction, respectively. According to these findings, ANFIS has resulted in more reliable performance which can be used as an acceptable model in the prediction of permeate flux. The optimum architecture for the ANN was obtained 5-22-1 whilst the architecture of ANFIS models for PVDF and MCE membranes were 3-7-12-12-1 and 4-9-24-24-1, respectively. The results of this study can be used to predict the amount of permeate flux in the absence of experimental data and/or for interpolation and extrapolation of the permeate flux. Practical applicationsOne of the problems in juice membrane clarification is the accumulation and deposition of rejected compounds on membrane surfaces or inside its pores which results in a membrane fouling. On the other hand, several parameters can have influence on fouling and predictions of juice permeate flux during the membrane processing whereas they are important in industrial applications. Therefore, providing a model which able to predict the permeate flux having the value of effective input parameters seems to be useful. In this regard, several artificial methods can be used.

PIH29 - DEVELOPMENT OF A DECISION AID PROTOTYPE FOR PARENTS CONSIDERING TUBE FEEDING FOR THEIR CHILDREN

Parents want to be more involved in medical decision-making for their children. However, the way information is provided in clinical practice might not facilitate shared decision-making (SDM) with physicians. We aimed to develop a Patient Decision Aid (PDA) prototype for parents considering enteral tube feeding options for their children to promote SDM. A PDA prototype was generated according to the International Patient Decision Aids Standards (IPDAS): 1) Establishing a steering committee (pediatric gastroenterologists [n=4] and parents [n=2]) to lead the project, 2) Conducting a needs and preferences assessment (literature review and focus groups with pediatricians and parents), and 3) Designing the PDA prototype. Input from healthcare professionals and parents was used to iteratively develop the PDA. The development of the final PDA will undergo two additional phases: pilot-testing (alpha-testing) with users to evaluate acceptability and field tests (beta-testing) in real life conditions. The PDA prototype addresses two feeding options: to start tube feeding (nasogastric or gastrostomy route) and the possibility to change the route of administration (continue with nasogastric or change to gastrostomy). The prototype approaches the main parts of a PDA, and reflects parents’ needs: 1) Information: general information on enteral feeding, comparison of feeding options, an exercise to detect problems in current feeding, frequently asked questions, parent experiences; 2) Preferences: a rating system (10-point scale) for values clarification, including statements to address the concerns and importance attributed to certain nasogastric and gastrostomy feeding issues; and 3) Resume of preferences and questions to be discussed with the physician. We developed a PDA prototype about feeding options following the systematic process proposed by IPDAS. The prototype will undergo two additional phases to check its acceptability and effectiveness. The final PDA will be ready for the use in clinical practice to promote SDM consistent with personal values.

\u201cThey do not see us as one of them\u201d: a qualitative exploration of mentor mothers\u2019 working relationships with healthcare workers in rural North-Central Nigeria

BackgroundIn HIV programs, mentor mothers (MMs) are women living with HIV who provide peer support for other women to navigate HIV care, especially in the prevention of mother-to-child transmission of HIV (PMTCT). Nigeria has significant PMTCT program gaps, and in this resource-constrained setting, lay health workers such as MMs serve as task shifting resources for formal healthcare workers and facility-community liaisons for their clients. However, challenging work conditions including tenuous working relationships with healthcare workers can reduce MMs’ impact on PMTCT outcomes. This study explores the experiences and opinions of MMs with respect to their work conditions and relationships with healthcare workers.MethodsThis study was nested in the prospective two-arm Mother Mentor (MoMent) study, which evaluated structured peer support in PMTCT. Thirty-six out of the 38 MMs who were ever engaged in the MoMent study were interviewed in seven focus group discussions, which focused on MM workload and stipends, scope of work, and relationships with healthcare workers. English and English-translated Hausa-language transcripts were manually analyzed by theme and content in a grounded theory approach.ResultsBoth intervention and control-arm MMs reported positive and negative relationships with healthcare workers, modulated by individual healthcare worker and structural factors. Issues with facility-level scope of work, workplace hierarchy, exclusivism and stigma/discrimination from healthcare workers were discussed. MMs identified clarification, formalization, and health system integration of their roles and services as potential mitigations to tenuous relationships with healthcare workers and challenging working conditions.ConclusionsMMs function in multiple roles, as task shifting resources, lay community health workers, and peer counselors. MMs need a more formalized, well-defined niche that is fully integrated into the health system and is responsive to their needs. Additionally, the definition and formalization of MM roles have to take healthcare worker orientation, sensitization, and acceptability into consideration.Trial registrationClinicaltrials.gov number NCT01936753, registered September 3, 2013.

Removal of Some Heavy Metals from Industrial Wastewater by Lemmna Minor

Treatment of industrial wastewater by constructed wetland system for the removal of heavy metals consisting of clarification and Lemna minor (duckweed) system was studied under experimental conditions through design, construction and operating pilot plant. This plant was operated with a constant hydraulic retention time of 2 hr and 10 days for clarifier and duckweed tanks respectively. The potential of duckweed has been investigated to accumulate Cd, Cr, Ni and Pb present in a combined industrial wastewater. The experiments results show that the average removal efficiency of Cd, Cr, Ni and Pb were 44.93%, 32.26%, 74.48%, and 79.1 respectively. Duckweed plant is a poor accumulator for Cd. While it is a hyperaccumulator for Pb, Cr and Ni. Also, the removal percentages of these heavy metals have significant positive linear correlation with the pH reduction percentage and increases in acidic solution (pH < 7). Therefore pH highly affects the removal efficiency of these metals from wastewater. Duckweed shows promise for the removal of heavy metals from industrial wastewater which makes duckweed a good species for phytoremediation activities. Duckweed based treatment systems are a cost-effective and reliable supply of acceptable quality water for river rehabilitation and reuse for other purposes.

An Advanced Clarification Process for Treating Produced Waters

Summary An advanced clarification process that was based on enhanced floc removal with magnetite and magnetic ballast [M2 Water Treatment's Magnetic Ballast Clarification (MBC) system] was evaluated in a field study at a hydraulic-fracture wastewater disposal site in southwest Texas. In this process, suspended solids are chemically flocculated in the presence of magnetite, rendering dense floc particles that are also magnetic. Flocculated solids with high settling rates are removed by gravity separation. The settled solids are then removed by use of drum-styled magnetics. Magnetite is recovered and reused. Although technically called clarification, the MBC process is governed by magnetic flux as opposed to gravity forces, allowing for a much smaller unit footprint, a unit that is portable for mobile use, and more dynamic control compared with conventional clarification. Produced water from a total of nine wells was processed during a period of several weeks in July and August 2015 in a 5-gal/min (171-B/D) pilot unit. Most tests were operated at approximately 3.1 gal/min (106 B/D) for consistency with the highly variable wastes encountered. Treated water sufficiently met criteria for reuse on the basis of oil and grease (O&amp;G), total suspended solids, and turbidity removal. The cost included two hypothetical treatment-plant sizes: a local processing unit plant (2,380 B/D or 100,000 gal/D) and a larger regional treatment system (11,900 B/D or 500,000 gal/D). Costs ranged from USD 0.79/bbl for the smaller treatment option to USD 0.22/bbl for the larger option, which included chemical costs and amortized (10 years) capital costs, installation, and labor. Estimates were based on assumptions for water requirements and treatment needs in the Barnett, Marcellus, and Eagle Ford shale plays, and included assumptions on freshwater availability, trucking costs, and treatment costs.

Experimental evaluation of helically coiled tube flocculators for turbidity removal in drinking water treatment units

The constant need to improve water treatment techniques allows for the emergence of new technologies for obtaining adequate water, both in terms of quality and quantity. In order to obtain an efficient, rapid and low-cost clarification system, this study proposes the use of helically coiled tubes (HCTs) as a coagulation-flocculation reactor coupled with a conventional decanter system. Eighty-four (84) turbidity removal tests were performed to evaluate the proposed clarification system, while varying hydraulic and geometrical parameters in HCTs. Removal efficiency values higher than 80% were obtained (with a maximum removal efficiency of 86.2%), presenting better results than systems using baffled tanks, which are traditionally applied for water treatment purposes in developing countries. In addition, significantly lower processing times (lower than 2 min, about 10% of baffled tank processing times) were observed for high efficiency process values, indicating that this clarification system can be useful in rational design of coagulation-flocculation units. It should be noted that the turbidity removal efficiency results obtained (with a rising-then-decreasing behaviour over time) differ significantly from those obtained by the commonly used models for flocculation evaluation (with asymptotic behaviour over time), presenting a maximum absolute percentage deviation of 48.9%, and indicating caution in the use of such models for alternative flocculation unit evaluation. Keywords: flocculation, drinking water, turbidity, turbidity removal efficiency, helically coiled tubes

Settling of virgin olive oil from horizontal screw solid bowl in static conditions.

This work was aimed to study the clarification efficiency of natural decantation in settling tank on virgin olive oil obtained from a two-ways continuous process. For this purpose, the impurities content of the virgin olive oil were monitored during settling process in settling tank at two different depths. Efficiency of purging system was determined for two days. The experiments were performed at industrial scale during three crop years. During the first minutes of settling was observed an ascent of the smaller organic particles of the oil. Then, most of the virgin olive oil impurities were settled at 300min, independently of the initial content of virgin olive oil. Finally, oil decantation showed slower rate. Higher clarification values were obtained for those decanter oils with higher impurities content, achieving clarification percentages between of 62.69 and 95.91% at 48h of settling. The highest settling efficiency was observed for those decanter oils with initial higher impurities content. The purging system used in the settling tanks was not able to remove the most of settled impurities since a considerable amount of the impurities remained in the tank after 48h, between 13.6 and 71.41% for the studied oils. In the tank purges was observed important oil losses. Therefore, decantation was not an efficient system for oil clarification since its settling capacity varied depending on the initial impurities content and due to the settled impurities can not be removed fully by purging system.

How clarification systems can affect virgin olive oil composition and quality at industrial scale

The effect of two different clarification systems, vertical centrifugal separator (VCS) with minimal water addition, and conical bottom settling tank (CBST), on virgin olive oil (VOO) composition and quality was studied at industrial scale for three crop years. In general, for the studied clarification systems, higher clarification values were reached for horizontal screw solid bowl (HSSB) oils with higher moisture and solid content. VCS showed higher clarification efficiency for HSSB oils with higher moisture and solid content. No notable differences were observed on the quality indices between evaluated clarification systems. Phenolic compounds showed a significant decrease when the HSSB oils were clarified by CBST. In general, a better sensory score was observed when the oils were clarified by VCS.Practical applications: The VCS with a minimal water addition could result a better option to produce VOO of improved quality, since is an efficient and quick operation that reduces the contact between oil and the remaining water and impurities content during the storage stage. This leads to prolong VOO shelf‐life and conservation of positive sensory notes, due to preservation of the quality indexes and minor components. Besides, this clarification system reduces the water consumption and generated wastewater regarding to conventional vertical centrifugation, and therefore can be considered more environmentally friendly.Effect of two different clarification systems (vertical centrifugal separator with minimal water addition and conical bottom settling tanks) on the virgin olive oil quality parameters, composition, and sensory characteristics.

Brazilian legal and bioethical approach about donation for research and patents of human body parts.

The aim of this paper is to explain why the Brazilian legal system does not accept commercialization or commodification of human body parts, including genes or cells. As a consequence, in Brazil, the donation of human body parts for research-including basic or translational-must be made altruistically. For the same reason, the Brazilian patent system cannot be applied to human parts, cells or genes. Here, we present a qualitative analysis of juridical, bioethical, and social reasoning related to the legal status of human body parts especially in biobanks, as well as a description of the Brazilian legal system for clarification. Our aim is to discuss the responsibility of researchers for making available the scientific information resulting from scientific research and biobank storage of human body parts and to ensure the free utilization of knowledge in human health research.

Una vuelta a los valores centrales en medicina de familia

Family medicine has to continually reinvent itself around a core of values that constitutes its navigation system. But accurate data on its impact on the health of people will account for how far the values are actually being implemented. Thus, we can say that family medicine is a specialty based on values and as well as evidence based. The absence of a clarification system of values or its implementation threatens its very existence. Some of the values that are reviewed have shown great recognition and survival over time. Others are presented because they seem sufficiently significant. These are: people, comprehensiveness, trust relationship, patient-centred method, accessibility, continuity, family unity and the community, teamwork, sustainability of the health system, and continuous improvement.

IT技術を使ったリモート境界明確化システム「リ・ディファインシステム」の開発

IT技術を使ったリモート境界明確化システム「リ・ディファインシステム」の開発

Three-dimensional model of phase diagram of Au-Bi-Sb system for clarification of thermodynamic calculations

A three-dimensional (3D) computer model of a T–x–y-diagram for an Au-Bi-Sb system is developed. It is established that it consists of 60 surfaces and 24 phase areas. It is used to show that works devoted to experimental studies and thermodynamic calculations of this system miss two surfaces and two phase areas in the iso- and polythermic sections.

Evaluation and comparison of water treatment plants efficiency and clarifiers performance in removing pollutants in water treatment plants of Tehran, Iran

Water treatment is performed using some conventional processes including coagulation, flocculation, sedimentation (clarification), and filtration. Due to the importance of clarification unit in potable water treatment, extensive studies on its advantages and disadvantages elucidate new horizons for evaluation of Accelerator and Pulsator. In this study, four water treatment plants in Tehran were compared with each other in terms of physical and chemical analysis, effluent water from clarifier unit, and effluent of treated water during 6 months from June to October 2012. Results showed the average turbidity in all plants is below standard except the plant No. 5. The total organic carbon (TOC) removal efficiency was undesirable in the both clarification systems (Accelator and Pulsator). On the other hand, TOC removal in Pulsator unit was monitored 40% more than that in Accelator unit. The TDS level was increased during the time period; however, the level lied down standard level. Pulsator is more efficient than Accelator in iron removal. The level of effluent iron in Accelator is more than that in Pulsator referring to iron escape from Accelator. Effluent iron in both systems is lower than the standard values. According to the consumption of chemical coagulants and coagulant aids, Accelator system consumes more than that of Pulsator system thus adding to the overall associated costs of the system. Effluent water in pulsator systems offer better quality than Accelator systems. Moreover, Pulsator system showed better resistance against qualitative and quantitative shocks on raw water.