scholarly journals Interaction between Biological Nitrogen Removal Processes and Operating Parameters: A Review

2020 ◽  
Vol 12 (4) ◽  
pp. 757-774
Author(s):  
M. S. I. Mozumder ◽  
M. D. Hossain
Keyword(s):  
Nitrogen Removal ◽  
Culture Medium ◽  
Human Life ◽  
Ammonia Concentration ◽  
Optimum Operating ◽  
Operating Parameters ◽  
Ammonium Oxidation ◽  
Advantages And Disadvantages ◽  
Removal Processes ◽  
Removal Technique

Nitrogen, mostly in the form of ammonia or nitrate containing wastewater deteriorated the water quality which simultaneously affects environment, plants, animals and human life. A number of researchers nowadays are conducting research to find out efficient and cost effective nitrogen removal technique along with optimum operating parameters. It is very important to uncover the optimum range of each parameter. In this study, it was winnowed to elicit the optimum operating ranges of dissolved oxygen concentration, temperature, pH, free ammonia concentration, nitrate concentration and culture medium. The nitrogen removal techniques were compared, evaluated considering advantages and disadvantages of them. Partial nitrification combined with anaerobic ammonium oxidation was found most prospective nitrogen removal technique for wastewater treatment compare to other techniques (conventional nitrification-denitrification over nitrate/nitrite, anammox, SND etc.) due to less oxygen consumption (62.5 % less), less sludge production, no carbon requirement, single reactor used and energy efficiency. SND process was more economical due to faster consumption of ammonia, nitrite and nitrate. There was various culture mediums which had a favorable or detrimental effect on specific nitrogen removal processes. However for desired bacteria culture for specific application, suitable culture medium needs to be selected considering the optimal operating parameters for microbial growth.

scholarly journals Technical Note: Simultaneous measurement of sedimentary N<sub>2</sub> and N<sub>2</sub>O production and new <sup>15</sup>N isotope pairing technique

2013 ◽  
Vol 10 (4) ◽  
pp. 6861-6898 ◽  
Author(s):  
T.-C. Hsu ◽  
S.-J. Kao
Keyword(s):  
Nitrogen Removal ◽  
Simultaneous Measurement ◽  
Sediment Cores ◽  
Technical Note ◽  
New Method ◽  
Ammonium Oxidation ◽  
N2o Production ◽  
Relative Contribution ◽  
Isotope Pairing ◽  
Removal Processes

Abstract. Dinitrogen (N2) and/or nitrous oxide (N2O) are produced through denitrification, anaerobic ammonium oxidation (anammox) or nitrification in sediments, of which entangled processes obfuscate the absolute rate estimation of gaseous nitrogen production from individual pathway. Recently, the classical isotope pairing technique (IPT), the most common 15N-nitrate enrichment method to quantify denitrification, has been modified by different researchers to (1) discriminate relative contribution of N2 production by denitrification from anammox or to (2) provide more accurate denitrification rate by considering both N2O and N2 productions. Both modified methods, however, have deficiencies such as overlooking N2O production in case 1 and neglecting anammox in case 2. In this paper, a new method was developed to refine previous methods. We installed cryogenic traps to pre-concentrate N2 and N2O separately, thus, allowing simultaneous measurement for two gases generated by one sample. The precision is better than 2% for N2 (m/z 28, m/z 29 and m/z 30), and 1.5% for N2O (m/z 44, m/z 45 and m/z 46). Based on the six m/z peaks of the two gases, we further revised IPT formulae to truthfully resolve the production rates of N2 and N2O contributed from 3 specific nitrogen removal processes, i.e. N2 and N2O from denitrification, N2 from anammox and N2O from nitrification. To validate the applicability of our new method, incubation experiments were conducted using sediment cores taken from the Danshuei estuary in Taiwan. We successfully determined the rates of aforementioned nitrogen removal processes. Moreover, N2O yield was as high as 66%, which no doubt would significantly bias previous IPT approaches when N2O was not considered. Our new method not only complements the previous IPT but also provides more comprehensive information to advance our understanding of nitrogen dynamics through the water-sediment interface.

Numerical modeling of nitrogen removal processes in biofilters with simultaneous nitritation and anammox

2013 ◽  
Vol 67 (3) ◽  
pp. 549-556
Author(s):  
Shun Shi ◽  
Wendong Tao
Keyword(s):  
Nitrogen Removal ◽  
Ammonium Concentration ◽  
Ammonia Oxidizing Bacteria ◽  
Ammonium Oxidation ◽  
Nitrite Oxidation ◽  
Ammonium Removal ◽  
Natural Treatment Systems ◽  
Natural Treatment ◽  
Removal Processes ◽  
Startup Period

This study developed a simple numerical model for nitrogen removal in biofilters, which was designed to enhance simultaneous nitritation and anaerobic ammonium oxidation (anammox). It is the first attempt to simulate anammox together with two-step nitrification in natural treatment systems, which may have different kinetic parameters and temperature effects from conventional bioreactors. Prediction accuracy was improved by adjusting kinetic coefficients over the startup period of the biofilters. The maximum rates of nitritation and nitrite oxidation increased linearly over time during the startup period. Simulations confirmed successful enhancement of simultaneous nitritation and anammox (SNA) in the biofilters, with anammox contributing 35% of ammonium removal. Effluent ammonium concentration was affected by influent ammonium concentration and the maximum nitritation rate, and was insensitive to the maximum nitrite oxidation rate and anammox substrate factor. Ammonium removal via SNA was likely limited by biomass of aerobic ammonia oxidizing bacteria in the biofilters. The developed model is a promising tool for studying the dynamics of nitrogen removal processes including SNA in natural treatment systems.

scholarly journals A Better MLE Nitrification Process Adopted from STOAT Simulation Experiments

2021 ◽  
Vol 43 (6) ◽  
pp. 443-452
Author(s):  
Taewook Kim ◽  
Sunjoo Cho ◽  
Sung-Hyun Kwon ◽  
Daechul Cho
Keyword(s):  
Nitrogen Removal ◽  
Water Conservation ◽  
Reduction Rate ◽  
Ammonia Concentration ◽  
Nitrification Rate ◽  
Process Variables ◽  
Simulation Experiments ◽  
Nitrification Process ◽  
Do Concentration ◽  
Removal Processes

Objectives : Nitrogen removal processes are very important in terms of water conservation. Among them, the MLE process has been difficult to optimize because it has many variations and required experiences in operation.Methods : In this work, we quantitatively analyzed the nitrification of the MLE process using the STOAT simulation program. In particular, we attempted to improve nitrification rate even at lower water temperatures.Results and Discussion : As a result, more than 93% ammonia was nitrificated when the water temperature was above 20℃, and a lower reduction rate of ammonia was observed when the temperature was below 15℃. Simulations applying three process variables (MLSS, DO concentration, and RAS) were carried out once or several times to increase nitrogen removal efficiency at 10℃, and the most efficient variable was ‘RAS increase’(55% reduction of ammonia).Conclusions : For more efficient nitrification rate, simultaneous increases in RAS and DO were required. In this case, the ammonia concentration in the effluent dropped by 61.4% and it was desirable to increase the MLSS return volume for T-N concentration reduction.

Nitrogen removal from wastewater treatment lagoons

1999 ◽  
Vol 39 (6) ◽  
pp. 191-198 ◽  
Author(s):  
Timothy J. Hurse ◽  
Michael A. Connor
Keyword(s):  
Wastewater Treatment ◽  
Nitrogen Removal ◽  
Treatment Plant ◽  
Ammonia Removal ◽  
Contour Plot ◽  
Removal Mechanism ◽  
Dissolved Oxygen Concentration ◽  
Physical Processes ◽  
Contour Plots ◽  
Removal Processes

In an attempt to gain a better understanding of ammonia and nitrogen removal processes in multi-pond wastewater treatment lagoons, an analysis was carried out of data obtained during regular monitoring of Lagoon 115E at the Western Treatment Plant in Melbourne. To do this, a contour plot approach was developed that enables the data to be displayed as a function of pond number and date. Superimposition of contour plots for different parameters enabled the dependence of ammonia and nitrogen removal rates on various lagoon characteristics to be readily assessed. The importance of nitrification as an ammonia removal mechanism was confirmed. Temperature, dissolved oxygen concentration and algal concentration all had a significant influence on whether or not sizeable nitrifier populations developed and persisted in lagoon waters. The analysis made it evident that a better understanding of microbial, chemical and physical processes in lagoons is needed before their nitrogen removal capabilities can be predicted with confidence.

scholarly journals A Review of Remote Sensing Image Dehazing

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3926
Author(s):  
Juping Liu ◽  
Shiju Wang ◽  
Xin Wang ◽  
Mingye Ju ◽  
Dengyin Zhang
Keyword(s):  
Remote Sensing ◽  
Data Driven ◽  
Future Research ◽  
Research Focus ◽  
Image Dehazing ◽  
Surface Information ◽  
Haze Removal ◽  
Advantages And Disadvantages ◽  
Extra Information ◽  
Removal Technique

Remote sensing (RS) is one of the data collection technologies that help explore more earth surface information. However, RS data captured by satellite are susceptible to particles suspended during the imaging process, especially for data with visible light band. To make up for such deficiency, numerous dehazing work and efforts have been made recently, whose strategy is to directly restore single hazy data without the need for using any extra information. In this paper, we first classify the current available algorithm into three categories, i.e., image enhancement, physical dehazing, and data-driven. The advantages and disadvantages of each type of algorithm are then summarized in detail. Finally, the evaluation indicators used to rank the recovery performance and the application scenario of the RS data haze removal technique are discussed, respectively. In addition, some common deficiencies of current available methods and future research focus are elaborated.

Sustaining Development of Environmental Education in National Political and Curriculum Priorities

1992 ◽  
Vol 8 ◽  
pp. 115-131 ◽  
Author(s):  
Annette Greenall Gough
Keyword(s):  
Sustainable Development ◽  
Environmental Education ◽  
Human Life ◽  
Historical Context ◽  
Policy Formulation ◽  
Conservation Strategy ◽  
Resource Base ◽  
Advantages And Disadvantages ◽  
World Conservation ◽  
Environmental Education Policy

The purpose of this paper is to explore the relationship between national economic and political priorities and environmental education policy formulation and curriculum strategies. This relationship will be placed in the historical context of developments in environmental education in Australia from 1970 until the present and will be analysed in terms of the ideological and pedagogical stances implicit, and explicit, in the developments during this period. I will argue that the emphasis throughout the period has been to sustain the development of environmental education without any questioning of why, what and how this development should occur.‘Sustainable development’ has become a slogan for governments, industry and conservation groups in recent times. It was the subtitle for the World Conservation Strategy (IUCN 1980) and the National Conservation Strategy for Australia (DHAE 1984) - living resource conservation for sustainable development - and was popularised in the report of the World Commission on Environment and Development, more commonly known as the Brundtland Report or Our Common Future (WCED 1987). The definition of sustainable development given in the World Conservation Strategy (IUCN 1980: section 1.3) and repeated in the National Conservation Strategy for Australia (DHAE 1984: 12) is as follows:Development is…the modification of the biosphere and the application of human, financial, living and non-living resources to satisfy human needs and improve the quality of human life. For development to be sustainable it must take account of social and ecological factors, as well as economic ones; of the living and nonliving resource base; and of the long term as well as the short term advantages and disadvantages of alternative actions.

scholarly journals Online Education as a New Practice of Humanism

2016 ◽  
Vol 18 (1) ◽  
pp. 117-124
Author(s):  
Svitlana Sylkina
Keyword(s):  
Online Education ◽  
Online Courses ◽  
Human Life ◽  
Educational Practice ◽  
Global Changes ◽  
Advantages And Disadvantages ◽  
Teacher Professional ◽  
Pass Through ◽  
Teacher Professional Knowledge ◽  
Contemporary Education

The current stage of the human progress is characterized by the high dynamism and global changes in all aspects of human life. The societies currently pass through a deep process of transformations that requires a new understanding of the human phenomenon and revision of humanism, new social practices, and forms of education. Higher school needs to achieve a very important goal. It is to create contemporary education paradigm, which would be based on shift from one paradigm centered on the University and teacher professional knowledge to a new one, which will be centered on the students and their needs in education. In this article, online education is observed as one of the ways of a new realization of humanism in educational practice. The author also analyzes the humanistic potential of Massive Open Online Courses (MOOC), its advantages and disadvantages as far as examined the prospects of online education. In conclusion the author mentions that online education due to its main characteristics (openness, accessibility, freedom of choice) is based on human rights and the principles of equality and could be identified as a new practice of humanism.

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