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1
Content available Treatment of Wastewater with High Ammonium Nitrogen Concentration
Marek Kinga, Pawęska Katarzyna, Bawiec Aleksandra
Journal of Ecological Engineering
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2021
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Vol. 22, nr 4
224--231
EN
The paper deals with the problem of wastewater treatment with specific physicochemical composition (increased ammonium nitrogen concentration) which were generated in Motor Rest Areas (MRA). Conventional biological wastewater treatment systems with activated sludge were used to purify the wastewater from sanitary equipment used in MRA. On the basis of the research conducted on four MRA, an attempt was made to determine the impact of the wastewater quality on biological wastewater treatment processes. The wastewater supplied to the treatment system was characterized by predominance of biologically non-degradable organic matter (average BOD/ COD ratio 4.39 – 10.42) as well as high concentration of ammonium nitrogen 273.9 – 334.55 mgN-NH4/dm3. The wastewater alkalinity determined by high content of ammonium nitrogen had a negative impact on the biological treatment processes. Unequal pollution load and temporary, high hydraulic load caused leaching of solid suspension from settling tank as well as leaching of particles of activated sludge from the reactor’s chamber. The lack of organic matter susceptible to biological decomposition makes it difficult to develop the biocenosis of activated sludge, and the limits of ammonium nitrogen concentration inhibit the nitrification processes.
2
Content available High impedance fault detection in radial distribution network using discrete wavelet transform technique
Suliman Mohammed Yahya, Alkhayyat Mahmood Taha
Archives of Electrical Engineering
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2021
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Vol. 70, nr 4
873--886
EN
Detecting high impedance faults (HIFs) is one of the challenging issues for electrical engineers. This type of fault occurs often when one of the overhead conductors is downed and makes contact with the ground, causing a high-voltage conductor to be within the reach of personnel. As the wavelet transform (WT) technique is a powerful tool for transient analysis of fault signals and gives information both on the time domain and frequency domain, this technique has been considered for an unconventional fault like high impedance fault. This paper presents a new technique that utilizes the features of energy contents in detail coefficients (D4 and D5) from the extracted current signal using a discrete wavelet transform in the multiresolution analysis (MRA). The adaptive neurofuzzy inference system (ANFIS) is utilized as a machine learning technique to discriminate HIF from other transient phenomena such as capacitor or load switching, the new protection designed scheme is fully analyzed using MATLAB feeding practical fault data. Simulation studies reveal that the proposed protection is able to detect HIFs in a distribution network with high reliability and can successfully differentiate high impedance faults from other transients.
3
Content available Microbiological Risk Assessment and Bioprocess Engineering
Płaza G., Achal V., Kumari D.
Multidisciplinary Aspects of Production Engineering
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2018
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Vol. 1, Iss. 1
233--239
EN
The Europe 2020 strategy (European Commission, 2010) calls a bioeconomy as a key element for smart and green growth in Europe. The development of a greener and more resource-efficient economy gives rise to new technologies and materials, which in turn may result in increased exposure to biological agents or combinations of different potentially harmful factors. For example, the expanding recycling industry employs an increasing number of workers which have to face various health problems (pulmonary, gastrointestinal and skin problems) as a result of exposure to biological agents such as airborne microorganisms. However, specific numbers for occupational diseases in this sector are still lacking. There are various workplaces and professional activities especially from the green industry for which exposure to microbiological agents occur unexpectedly and in an uncontrolled way. The issue of uncontrolled microbial exposure there is for example in waste treatment and for retrofitting activities, both growing sectors of employment in a greening society. As a result of the problem in the green industrial sector, there is a need to develop tools for risk assessment and prevention measures. In order to be able to develop suitable risk management strategies, a further development of detection and identification methods for biological agents is needed to cover the whole spectrum of microorganisms. the present paper focuses on the microbiological risk assessment in the context of the development of new and safe industrial products and processes of green industry (bioindustry and bioprocessing).
4
Content available remote Wavelet-Based and Database Approach for Locating Faulty Section of High Impedance Fault in a Distribution System
Ali M. S., Bakar A. H. A., Mokhlis H., Arof H., Illias H. A.
Przegląd Elektrotechniczny
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2013
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R. 89, nr 1a
211--218
EN
Locating a faulty section of the high impedance fault (HIF) in a power system network is a major challenge especially for a distribution network. This is due to the effect of the complexity of the distribution network such as branches, non-homogenous lines and high fault impedance that results in variation of fault locations. In this paper, analysis of fault locations using Discrete Wavelet Transform-based Multi-Resolution Analysis (MRA) has been proposed. A three-phase voltage signal measured at the main substation is analyzed to locate the high impedance fault. The 1st, 2nd and 3rd levels of detailed coefficient resolution for each phase were used for the classification of fault locations using the proposed method. The simulation was conducted on a 38-node distribution network system in a national grid in Malaysia using PSCAD software. The proposed method has successfully determined the actual fault location of a high impedance fault.
PL
W artykule przedstawiono analizę metody lokalizacji awarii w sieci energetycznej, wykorzystującej analizę wielo-wynikową (ang. Multiresolution Analysis), opartą na dyskretnej transformacji falkowej. Analizie poddawany jest sygnał pomiarowy napięcia trójfazowego w podstacji. Przeprowadzono badania symulacyjne w programie PSCAD na systemie dystrybucji energii elektrycznej o 38 korzeniach w malezyjskich państwowych sieciach energetycznych.
5
Content available remote Neuronowa analiza aktywacyjna jako metoda podstawowa w metrologii chemicznej
Polkowska-Motrenko H.
Postępy Techniki Jądrowej
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2005
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z. 1
19-25
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