scholarly journals Disinfection processes and mechanisms in wastewater stabilization ponds: a review

2018 ◽  
Vol 26 (4) ◽  
pp. 417-429 ◽  
Author(s):  
Lei Liu ◽  
Geof Hall ◽  
Pascale Champagne
Keyword(s):  
Wastewater Treatment ◽  
Review Paper ◽  
Pathogen Removal ◽  
Stabilization Ponds ◽  
Treatment Technologies ◽  
Definition Of ◽  
Maintenance Requirements ◽  
The Relationship ◽  
Critical Overview ◽  
Wastewater Stabilization Ponds

Wastewater stabilization ponds (WSPs) have been proven to be economical alternatives to conventional wastewater treatment technologies due to their unique advantages including ease of operation, minimal energy input, and minimal maintenance requirements. Their reported high pathogen removal efficiencies have made WSPs a popular choice for wastewater treatment, especially as tertiary lagoons. This paper provides a critical overview of the various disinfection processes and mechanisms that occur in WSPs. A thorough review of the removal or attenuation mechanisms for bacterial, viral, protozoan, and helminthic pathogens is presented. Factors that impact the removal efficiency of pathogenic organisms may include sunlight, pH, dissolved oxygen, temperature, sedimentation, attachment, hydraulic retention time, pond depth, predation and nutrient availability; the relationship between these factors is also discussed. The purpose of this review paper is to utilize the current understanding of pathogen removal mechanisms in pond systems to improve the operation and design of WSPs, and more importantly, to provide guidance for the definition of regulations with respect to pathogen removal in eco-engineered wastewater treatment systems such as WSPs.

Decentralised wastewater treatment technologies from a national perspective: at what cost are they competitive?

2005 ◽  
Vol 5 (6) ◽  
pp. 145-154 ◽  
Author(s):  
M. Maurer ◽  
D. Rothenberger ◽  
T.A. Larsen
Keyword(s):  
Wastewater Treatment ◽  
Western Europe ◽  
New Technologies ◽  
Sewer Systems ◽  
Wastewater Systems ◽  
Treatment Technologies ◽  
Wastewater Infrastructure ◽  
National Perspective ◽  
Maintenance Requirements

In this paper we estimate at what cost decentralised wastewater treatment can be competitive compared with conventional centralised technologies. For the current wastewater infrastructure in Western Europe and North America, typical replacement costs are 2,600 US$/cap for large countries and 4,800 US$/cap for small ones. In the same literature, average annual operating costs are reported to be 3.8% of replacement costs. However, if a long-term interest rate of 3% is consistently applied, this value increases to 4.7% for small countries and 5.5% for large ones. Assuming that alternative wastewater systems will only be accepted if their costs are similar to existing ones, the possible investments for alternative wastewater treatment technologies are calculated. Between 640 and 2,170 US$/cap can be invested in new technologies for scenarios without a sewer system. The corresponding figures for scenarios with sewer systems are between 260 and 680 US$/cap. Acceptable maintenance requirements are calculated on the basis of unit size. Transition periods are not accounted for.

scholarly journals Research of sewage intake of small settlements in dry weather

Vestnik MGSU ◽  
2019 ◽  
pp. 225-236 ◽  
Author(s):  
Irina I. Ivanenkо ◽  
Kseniya S. Senicheva
Keyword(s):  
Wastewater Treatment ◽  
Sewage Treatment ◽  
Full Scale ◽  
Leningrad Region ◽  
Design Practice ◽  
Daily Consumption ◽  
Sewage Treatment Plants ◽  
Large Cities ◽  
Treatment Technologies ◽  
Definition Of

Introduction. Attempts to apply classical wastewater treatment technologies to small volumes are often impossible due to the high irregularity of wastewater inflows, and fundamental fluctuations in the composition of wastewaters, which are very diverse in comparison with medium and large cities. At three sites located in the Leningrad Region, full-scale measurements of wastewater discharges from settlements with a population of 1000 people and an industrial enterprise were carried out in order to determine the irregularity coefficients of wastewater during the dry season. The irregularity coefficients used in the design practice for such objects differ greatly in their values, as determined in the process of analyzing the literature data, which, when designing head sewage treatment plants, can lead to significant errors in calculations. Materials and methods. Measurement of a daily consumption of sewage flowmeters counters, elimination of improbable values, definition of consumption in dry weather, comparison of these various objects. Results. Mathematical dependences are proposed for describing fluctuations in the daily coefficient of irregularity of waste during the year. It was proposed to describe the weekly fluctuation of expenses with the help of the weekly coefficient of non-uniformity and its values were determined for the studied objects. A method has been developed for determining estimated costs for small objects with a population of 1000 people. Conclusions. The developed technique allows to predict the size of coefficient of daily unevenness within a year in dry weather for small settlements with number of inhabitants of 1000 people and a small share of production drains. It is possible to recommend values of coefficients of week unevenness.

Employee loyalty and organizational performance: a critical survey

2014 ◽  
Vol 27 (5) ◽  
pp. 839-850 ◽  
Author(s):  
Olivia Guillon ◽  
Cécile Cezanne
Keyword(s):  
Organizational Performance ◽  
Design Methodology ◽  
Critical Survey ◽  
Employee Loyalty ◽  
Content Type ◽  
And Performance ◽  
Definition Of ◽  
The Relationship ◽  
Critical Overview

Purpose – The purpose of this paper is to clarify the relationship between employee loyalty and organizational performance. It starts with the idea that the employee loyalty creates value for the organization. This statement is widely endorsed in the literature although there is little consensus on the definition of loyalty. The paper proposes a refined synthesis of the literature on the link between employee loyalty and organizational performance. Design/methodology/approach – The paper addresses the question of whether there is a robust positive link between employee loyalty and organizational performance. The paper starts by reviewing the various, sometimes divergent, approaches to employee loyalty in the literature and then compare the different indicators of loyalty in relation to their relevance to different indicators of performance. Findings – The paper provides a critical overview of the different existing conceptions of employee loyalty. It points out ambiguity about both the theoretical contours of the concept, and practical means of making it a source of value for the organization. The paper shows that the link between employee loyalty and performance varies according to the type of indicators used. Research limitations/implications – The paper highlights a variety of indicators for employee loyalty to their firm and for organizational performance. But much research remains to be conducted, notably on the managerial levers that might consolidate or improve organizational performance. Originality/value – This paper fulfills an identified need to survey a fragmented theoretical field of analysis.

scholarly journals Review paper. Does genius border on insanity? Part I: A relationship between creativity and the presence of psychopathological symptoms in bipolar disorder

2017 ◽  
Vol 18 (1) ◽  
pp. 25-33
Author(s):  
Olga Nowacka ◽  
Henryk Welcz ◽  
Hanna Karakuła-Juchnowicz
Keyword(s):  
Bipolar Disorder ◽  
Sexual Selection ◽  
General Population ◽  
Review Paper ◽  
Psychopathological Symptoms ◽  
Selection Processes ◽  
Definition Of ◽  
High Level ◽  
The Relationship ◽  
Natural And Sexual Selection

Abstract The theory linking the development of mental disorders with the processes of human evolution assumes that these disorders may be the result of a side effect of natural and sexual selection processes. Creativity is one of the adaptive features associated with the increased incidence of psychopathological symptoms (as compared to the general population). In this review paper, the definition of creativity has been characterized, and contemporary existing theories on its background, have been presented. Also, the paper describes the relationship between creativity and the presence of psychopathological symptoms. Special attention has been paid to the relationship between creativity and bipolar disorder. The research results prove the existence of a correlation between a high level of creativity and a higher prevalence of psychopathological symptoms, particularly concerning the symptoms of bipolar disorder spectrum.

Pathogen removal mechanisms in anoxic wastewater stabilization ponds

1996 ◽  
Vol 33 (7) ◽  
pp. 133-140 ◽  
Author(s):  
A. Almasi ◽  
M. B. Pescod
Keyword(s):  
Domestic Sewage ◽  
Pathogenic Microorganisms ◽  
Organic Loading ◽  
Pathogen Removal ◽  
Effluent Quality ◽  
Stabilization Ponds ◽  
Pathogenic Agents ◽  
Positive Effect ◽  
Wastewater Stabilization Ponds

Anoxic wastewater stabilization ponds can reduce land requirements by as much as two-thirds of that required for facultative ponds and can avoid the environmental nuisances of odour and corrosion, compared with anaerobic ponds. When effluent reuse is to be considered, the aim of wastewater treatment is not only to reduce degradable organic matter but also to remove pathogenic microorganisms. There are many pathogenic agents in domestic sewage and determination of all of them is not practically feasible, so faecal coliform organisms are normally estimated as indicators of health risk. It has been found that the volumetric organic loading on ponds affects pathogen removal inversely and temperature has a positive effect. This was confirmed in the present studies on “anoxic” ponds and, in addition, other environmental factors (light, pH, DO and ORP) were found to have influenced pathogen removal in these ponds, which were loaded in the range between conventional loadings for anaerobic and facultative stabilization ponds. However, pathogen removal in anoxic ponds was not found to be significantly better or worse than in anaerobic or primary facultative ponds and, therefore, maturation ponds would be required following anoxic ponds to achieve an effluent quality suitable for unrestricted irrigation.

scholarly journals Effect of Climatic Conditions on Treatment Efficiency of Wastewater Stabilization Ponds at Chokera, Faisalabad

2021 ◽  
Vol 40 (1) ◽  
pp. 75-81
Author(s):  
Hafiz Qasim Ali ◽  
Amir Farooq ◽  
Amir Farooq ◽  
Mohammad Laeeque Ahmed ◽  
Muhammad Akhtar
Keyword(s):  
Wastewater Treatment ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Climatic Conditions ◽  
Wastewater Management ◽  
Treatment Efficiency ◽  
Population Mixing ◽  
Stabilization Ponds ◽  
Low Efficiency ◽  
Wastewater Stabilization Ponds

Wastewater management is one of the biggest challenges in the world due to increase in population and industrialization. In Faisalabad (FSD), wastewater treatment is being done through Wastewater Stabilization Ponds (WSPs) at Chokera, which is one of the most economical methods of Wastewater Treatment (WWT). Various parameters were examined to check wastewater treatment efficiency of the ponds under diverse climatic conditions. These included Biochemical Oxygen Demand (BOD), pH, Chemical Oxygen Demand (COD), Turbidity, Copper, Total Solids (TS), Total Dissolved Solids (TDS) and Lead. Six locations which were selected for monitoring treatment efficiency, included inlet and outlet of treatment plant, influent of anaerobic ponds, effluent of anaerobic ponds, effluent of facultative ponds, and Pharang drain before and after blending with treated sewage. The testing was performed in two seasons (i.e. Winter 2015 and Summer 2016) in Environmental Engineering Laboratory, Department of Civil Engineering, The University of Lahore, Pakistan. BOD5 removal efficiency of the treatment plant was found 30.08% in winter and 51.74% in summer against designed value of 90% removal. Most of the parameters of the effluent were not meeting the Punjab Environmental Quality Standards (PEQS). The reasons of low efficiency are; variation in climatic conditions (i.e. less solar heat intensity, wind speed and ceased microbial activity in winter), lack of funds by government, increased population, mixing of industrial sewage with domestic sewage and less attention being paid to maintain the performance of Ponds. The study was carried out to assess and compare the efficiency of treatment plant with PEQS in two climatic conditions.

Time series relationships between chlorophyll-a, dissolved oxygen, and pH in three facultative wastewater stabilization ponds

2016 ◽  
Vol 2 (6) ◽  
pp. 1032-1040 ◽  
Author(s):  
J. Wallace ◽  
P. Champagne ◽  
G. Hall
Keyword(s):  
Time Series ◽  
Wastewater Treatment ◽  
Dissolved Oxygen ◽  
Chlorophyll A ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Chl A ◽  
Stabilization Ponds ◽  
In Series ◽  
Wastewater Stabilization Ponds

This study involved the evaluation of time-series relationships between chlorophyll-a (chl-a), dissolved oxygen (DO), and pH in three facultative wastewater stabilization ponds (WSPs) operated in series at a wastewater treatment plant in eastern Ontario, Canada.

ADMINISTRATIVE AND LEGAL STATUS OF THE CAPITAL OF UKRAINE - THE HERO CITY OF KYIV AS A GUARANTEE OF THE RIGHTS OF CITIZENS OF UKRAINE AND THE TERRITORIAL COMMUNITY OF THE CITY

2017 ◽  
Author(s):  
Oleksii Chepov ◽  
Keyword(s):  
Legal Status ◽  
Modern World ◽  
Legal Regime ◽  
Legal Doctrine ◽  
City Councils ◽  
The Social ◽  
District Management ◽  
Definition Of ◽  
The Relationship ◽  
The City

The qualitative and clear definition of the legal regime of the capital of Ukraine, the hero city of Kyiv, is influenced by its legislative enshrinement, however, it should be noted that discussions are ongoing and one of the reasons for the unclear legal status of the capital is the ambiguity of current legislation in this area. Separation of the functions of the city of Kyiv, which are carried out to ensure the rights of citizens of Ukraine and the functions that guarantee the rights of the territorial community of the city of Kyiv. In the modern world, in legal doctrine and practice, the capital is understood as the capital of the country, which at the legislative level received this status and, accordingly, is the administrative and political center of the state, which houses the main state bodies and diplomatic missions of other states. It is the identification of the boundaries of the relationship between the competencies of state administrations and local self-government, in practice, often raises questions about their delimitation and ways of regulatory solution. Peculiarities of local self-government in Kyiv city districts are defined in the provisions of the Law on the Capital, which reveal the norms of the Constitution in these legal relations, according to which the issue of organizing district management in cities belongs to city councils. Likewise, it is unregulated by law to lose the particularity of the legal status of the territory of the city. It should be emphasized that the subject of administrative-legal relations is not a certain administrative-territorial entity, but the social group is designated - the territorial community of the city of Kiev, kiyani. Thus, the provisions on the city of Kyiv partially ignore the potential of the territorial community.

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