The performance of vertical flow constructed wetland systems with special reference to the significance of oxygen transfer and hydraulic loading rates

The paper reviews the development of the vertical flow (VF) reed beds/constructed wetlands over the past 20 years. The performance of VF systems (and their use within hybrid systems) is analysed by reference to a number of brief case studies. The oxygen transfer rate (OTR) achieved is absolutely critical to the sizing of the systems. The author reviews the reported OTRs and comments on the existing design equations proposed for calculation of the area of beds. The 1st generation of VF systems used a set of parallel beds that were dosed one at a time in rotation and then rested for a period of days because there was considerable concern (based on early experience) that they would become clogged. In the past 10 years a number of new designs of 2nd generation VF beds have been built which make use of a single bed and hence operate without any resting periods. The hydraulic loading rate and the selection of the bed media, which are critical to the design and hence successful operation of these 2nd generation compact VF beds, are described. It is now possible to produce a very high quality of effluent from VF beds alone sized at 2 m2/pe when treating domestic sewage.

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Compact vertical flow constructed wetland systems - first two years’ performance

Water Science & Technology ◽

10.2166/wst.2003.0269 ◽

2003 ◽

Vol 48 (5) ◽

pp. 15-23 ◽

Cited By ~ 39

Author(s):

C.M. Weedon

Keyword(s):

Oxygen Transfer ◽

Transfer Rate ◽

Oxygen Transfer Rate ◽

Oxygen Demand ◽

Phosphate Removal ◽

Normal Operation ◽

Vertical Flow ◽

Average Percentage ◽

Load Rate ◽

Reed Bed

In order to move towards optimising wastewater treatment performance by vertical down-flow reed beds, user and installer demands were applied to design, resulting in the “compact vertical flow reed bed” (CVF bed). Performance data are presented for the two years since commissioning a CVF bed and pond system serving eight residents. Particular emphasis was placed on investigating oxygen transfer rate and susceptibility to hydraulic overloading. Average percentage concentration reduction effected by single passage through the bed exceeded 97% for suspended solids and biochemical oxygen demand, and 90% for ammoniacal nitrogen and total Kjeldahl nitrogen. The occurrence of nitrification and denitrification (up to 58%) within the same bed was clearly indicated. Percentage ortho-phosphate removal averaged 92% over the first 17 months’ operation and thereafter fell to approximately 45%. Faecal coliform density underwent an almost four log reduction. Oxygen transfer rate within the reed bed was between 28-36 gO2/m2.d. Normal operation was maintained until six times dry weather hydraulic load rate was exceeded, at which point surface flooding occurred. The capacity of a single vertical flow reed bed to achieve effective treatment of domestic sewage was demonstrated, with no requirement for reduced load rates, promising substantial advantages over established approaches.

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INFLUENCE OF THE BIOMASS CARRIER TYPE ON THE OXYGEN TRANSFER RATE OF THE MODIFIED SUBMERSIBLE ROTATING BIOFILTER

URBAN CONSTRUCTION AND ARCHITECTURE ◽

10.17673/vestnik.2020.04.8 ◽

2021 ◽

Vol 10 (4) ◽

pp. 60-68

Author(s):

Maram Ali SAIED ◽

Nikolay S. SERPOKRYLOV ◽

Vladimir V. NELIDIN

Keyword(s):

Oxygen Transfer ◽

Transfer Rate ◽

Rotation Speed ◽

Mass Transfer Rate ◽

Oxygen Transfer Rate ◽

Immersion Depth ◽

Treated Wastewater ◽

Technological Parameters ◽

Effi Ciency

The modifi ed submersible rotating biofi lter MSRB was developed and patented to improve the effi ciency and quality of treated wastewater from small sett lements in Syria by increasing the mass transfer rate and oxygen transfer rate of the drum-type rotating biofi lter without the need for additional aeration elements. The result of comparing the eff ect of two types of biomass carrier on the oxygen transfer rate OTR shows that the highest value of the OTR when using the fi rst biomass carrier (1) was 409 g/m3·h with a drum fi lling percentage of 60%, a rotation speed of 15 rpm and an immersion depth of 35% While the maximum value when using the second biomass carrier (2) was 518.95 g/m3·h with a drum fi lling percentage of 90%, a rotation speed of 15 rpm and an immersion depth of 15%. It can also be concluded that a change in the shape of the biomass carrier, as well as its density, signifi cantly aff ects the OTR of the biofi lter. In addition, changing the shape of the biomass carrier requires changing other technological parameters, such as the fi lling percentage of the drum, the depth of immersion and the rotation speed.

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MACRO PHOTOGRAMMETRY IN INVENTORY OF HISTORICAL ENGRAVINGS AT THE ROYAL CASTLE IN WARSAW

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-2-w9-795-2019 ◽

2019 ◽

Vol XLII-2/W9 ◽

pp. 795-800

Author(s):

D. Zawieska ◽

J. Markiewicz ◽

M. Łuba

Keyword(s):

Past History ◽

The Past ◽

Orientation Process ◽

Measuring Techniques ◽

Historical Objects ◽

Key Aspects ◽

The Impact ◽

Selection Of

Abstract. In the community historical objects play the role of witnesses of the past history. This creates an obligation to preserve and reconstruct them for future generations. Photogrammetric methods have been applied for those purposes for many years. In the process of development of inventory documentation, the key aspects related to the selection of appropriate measuring methods for particular objects and the creation of appropriate working conditions. At present, digital measuring techniques allow developing 3D photogrammetric documentation which is particularly valuable both, for conservators of historical objects, as well as for creating virtual museums. Particular attention should be paid to the utilisation of macro photography for that purpose which allows for recreating small fragments of historical details. The objective of this paper is to present possible use of macro photography for inventory of historical patterns engraved in brick walls of one of the cellars of the Royal Castle in Warsaw (Poland); they are called engravings or house marks. The cellar walls were made of bricks (20&times;10cm) on the stone foundations, where a prison was located in the 17th century. Prisoners left their drawings of signs and crests. Bricks are destroyed, some of them are moss-grown, so many engravings are hardly visible and their depths vary between 3 and 5mm. The Canon 5D Mark II camera with the 50 mm macro lens was used to inventory engravings together with the shadow-free flash, mounted on the lens and a special frame with bolts, being the photogrammetric control network. To ensure the high quality of the 3D model, a network of photographs were acquired from two different distances; they were processed with the use of SfM/MVS algorithms implemented in Agisoft PhotoScan software. The aim of this paper is to discusses the impact of selection of control points on the accuracy of the orientation process, the impact of the point cloud density on correct projection of the digital surface, the influence of the DSM resolution on details of projection of shapes and selection of orthorectification and mosaicking parameters on the accuracy of orthoimage generation.

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Selecting the future

Journal on Teaching Engineering ◽

10.24840/2795-4005_001.001_0005 ◽

2021 ◽

Vol 1 (1) ◽

pp. 113-132

Author(s):

Teresa Duarte ◽

António Lopes ◽

Lucas Da Silva

Keyword(s):

Higher Education ◽

Mechanical Engineering ◽

Higher Education Institutions ◽

Decision Makers ◽

First Year ◽

First Year Students ◽

The Past ◽

Very High ◽

Shed Light

In the last years, the Integrated Master in Mechanical Engineering (MIEM) at FEUP revealed a very high capability for attracting young students. However, the true reasons that determine the interest of the students in the Mechanical Engineering cycle of studies (CS) are not well understood. This paper tries to shed light on this question. A survey was prepared and applied to the first year students enrolled on MIEM in 2020-2021. The responses were analyzed statistically and organized comprehensively. The results show that the opinions of others, the quality and availability of information, the versatility and employability rates of the CS, the quality of training and the reputation of the HEI/CS are crucial. The findings can be further explored by the FEUP/CS decision makers to delineate policies envisaging strengthening the ability of Mechanical Engineering to compete for the best potential candidates to higher education. Indeed, the higher education institutions are aware that they have to fight for students in the global recruitment market and be more proactive than they used in the past.

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The effect of home and commercial laundering upon the wearing quality of ginghams and similar fabrics and the reliability of the consumer's judgement in the selection of these fabrics

10.32469/10355/65524 ◽

1928 ◽

Author(s):

◽

Cleora Eleanor Johnson

Keyword(s):

The Past ◽

Commercial Laundry ◽

Selection Of

The laundering of clothing and household articles is an ever present necessity of the homemaker. In the past, practically all of the laundry work was done in the home and generally by the housewife herself. The time came when this task was gradually transferred to a laudress or to a commercial laundry. Paralleling the trend toward commercial laundries, the invention of labor saving devices, such as power washers, irons, and mangles, has again made laundering an important home task.

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Determing of the Armed Forces Demands for Specific Kinds of Facilities

International conference KNOWLEDGE-BASED ORGANIZATION ◽

10.2478/kbo-2020-0015 ◽

2020 ◽

Vol 26 (1) ◽

pp. 100-105

Author(s):

Teodora Petrova ◽

Zhivo Petrov

Keyword(s):

Decision Making ◽

Project Success ◽

Armed Forces ◽

Specific Kind ◽

Final Choice ◽

Procurement Process ◽

Very High ◽

Selection Of

AbstractThe adequate financing of the first project’s stages, especially the decision making stage for supplying with specific kind of facility or equipment, will lead to a successful fulfilling of all other stages of the project. The procurement process which is directed to supplying of the armed forces necessary needs, includes a selection of the best technical decisions towards the proportion (ratio) between price/quality of the facility and/or the services. Therefore, the final choice of the technical decision should answer to the user demands (who sometimes demands not-approved very high requirements) only to level, at which this action will not be in danger for the project success.

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Effect of different management on quality and value production of pure beech stands in Slovakia

Central European Forestry Journal ◽

10.1515/forj-2017-0012 ◽

2018 ◽

Vol 64 (1) ◽

pp. 24-32

Author(s):

Igor Štefančík ◽

Michal Bošeľa ◽

Rudolf Petráš

Keyword(s):

Positive Impact ◽

Management Strategies ◽

Forest Research ◽

Beech Forests ◽

The Past ◽

Value Production ◽

Crown Thinning ◽

Individual Trees ◽

Selection Of

AbstractValue production is one of the most important information for comparing different management strategies in forestry. Although the value production of forest stands is affected by various factors (stem and assortment quality, stem dimension, stem injury, price of assortments), thinning can be considered as one of the most important one. This paper aims at the evaluation of qualitative and value production in homogeneous beech stands, which were managed by two different thinning types for period of 45 to 55 years: (i) – heavy thinning from below (C grade according to the German forest research institutes released in 1902) and (ii) – Štefančík´s free-crown thinning. The third variant was control (iii) – subplot with no interventions. Silvicultural quality characteristics of the lower half of the stem were assessed using a 4-class scale (A – the best quality, D – the worst quality). Assortment structure (commercial quality) was estimated for each stem by an assortment model developed in the past. Nearly 3,000 individual trees aged from 83 to 105 years from 23 subplots established across the Slovakia territory were assessed. The highest volume of the best silvicultural quality of stems (A class) has been reached in forests where Štefančík´s free-crown thinning was applied (57 – 85%) while the lowest (22 – 56%) on subplots with no management. The proportion of two best commercial quality assortments (I + II) was highest in forests managed by heavy thinning from below (21 – 29%) and the lowest when no treatment was applied (7 – 19%). The highest value production (expressed in € ha−1) was reached in the forests treated by free-crown thinning. Results suggested the overall positive impact of thinning on the increase of value production in beech forests. Particularly, the free-crown thinning focusing on selection of best quality trees should be preferred as it leads, besides its sufficient value production, to a higher vertical differentiation of the beech forests.

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On the development of methodology of source criticism in the area of philosophy of law

Genesis исторические исследования ◽

10.25136/2409-868x.2020.3.32442 ◽

2020 ◽

pp. 78-92

Author(s):

Vladimir Sergeevich Gorban

Keyword(s):

Philosophy Of Law ◽

Source Criticism ◽

The Past ◽

Political Ideas ◽

Legal Literature ◽

Negative Effect ◽

History Of ◽

Legal Methodology ◽

Selection Of

This article explores the problem of development of methodological framework of source criticism in the area of history of political and legal doctrines (history of philosophy of law). Deficit of the related developments in both, national and foreign legal literature, has a highly negative effect on the quality of selection of the source research material and formulation of valid scientific conclusions that allow conducting historical-philosophical and problematic-theoretical reconstructions of legal and political ideas of the past and modernity in a proper way. The scientific novelty of this work consists in substantiation of scientific importance and possibilities of practical application of such relevant vector of legal methodology as the methodology of source criticism in the area of philosophy of law (history of political and legal doctrines), which is interpreted not only as a set of instrumental cognitive acts, but also as a combination of principles and techniques of ensuring veracity of the content, concept and purpose of legal and political ideas of the past and modernity.

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How guidance on the use of interventional procedures is produced in different countries: An international survey

International Journal of Technology Assessment in Health Care ◽

10.1017/s0266462309090175 ◽

2009 ◽

Vol 25 (02) ◽

pp. 124-133 ◽

Cited By ~ 14

Author(s):

Jonathan Plumb ◽

Bruce Campbell ◽

Georgios Lyratzopoulos

Keyword(s):

Technology Assessment ◽

Interventional Procedures ◽

Response Rate ◽

Invasive Procedures ◽

The Past ◽

Assessment Systems ◽

The Status ◽

Surgical Operations ◽

Selection Of

Objectives:Technology assessment systems for interventional procedures (including surgical operations, minimally invasive procedures, and others) have lagged behind those for pharmaceutical treatments. Such systems have been introduced in some countries during the past decade amid debate about how they should be organized, but there is no collated information about where they exist or how they work. This study was designed to provide hitherto unavailable information about the existence, organization, methods, and outputs of systems aimed at influencing the use of interventional procedures in different countries.Methods:Data were gathered from a questionnaire survey of key informers associated with healthcare technology assessment (HTA) organizations in different countries.Results:Responses were received from key informers working for twenty-eight HTA organizations in twenty-five countries (response rate 83 percent). Information about a national system for assessing interventional procedures was obtained for fifteen countries. There was substantial variability in the type and funding of these organizations, the systems used for the selection of procedures, the types and sources of evidence used, the personnel involved in the appraisal of the evidence, the arrangements for consultation on the draft assessment, the format of assessment recommendations, the status of the guidance, and the use of guidance from other countries.Conclusion:Guidance on interventional procedures is produced variably in different countries—and not at all in some. Greater international collaboration in the assessment of new interventional procedures could help to optimize the efficiency of existing systems as well as the quality of the assessments, by capitalizing on the outputs from scarce (international) resources and expertise.

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