Search results

1

Factors Affecting the Performance of Double Chamber Microbial Fuel Cell for Simultaneous Wastewater Treatment and Power Generation

100%

Khan M. R., Amin M. S. A., Rahman M. T., Akbar F., Ferdaus K.

Polish Journal of Chemical Technology

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2013

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vol. 15

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issue 1

7-11

EN

Electricity generation from the readily biodegradable organic substrate (glucose) accompanied by decolorization of azo dye was investigated using a two-chamber microbial fuel cell (MFC). Batch experiments were conducted to study the effect of dye and substrate concentration on MFC performance. Electricity generation was not significantly affected by the azo dye at 300 mg/L, while higher concentrations inhibited electricity generation. The chemical oxygen demand (COD) removal and decolorization of dye containing wastewater used in the MFC were studied at optimum operation conditions in anode and cathode, 57% COD removal and 70% dye removal were achieved. This study also demonstrated the effect of different catholyte solutions, such as KMnO4 and K2Cr2O7 on electricity generation. As a result, KMnO4 solution showed the maximum electricity generation due to its higher standard reduction potential.

2

An assessment of water quality temporal variation in Sri Jayawardenapura Kotte canal, Sri Lanka

88%

Nishanthi K., Dushanan R., Mathanraj S., Priyadharshini C.

World News of Natural Sciences

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2021

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vol. 38

139-157

EN

Assessment of temporal variation of the water quality is an essential aspect of evaluating temporary changes in a water body caused by natural or artificial contributions. The study aims to assess the water quality temporal variation and the water quality index over the year from 2010 to 2019. Water sampling was carried out near the bridge of the Kotte canal. Water quality parameters such as pH, electrical conductivity (EC), temperature, dissolved oxygen (DO), ammonia, nitrate, phosphate, and chemical oxygen demand (COD) were determined to assess the quality of water at different periods. It has been calculated based on the standard of the central environmental authority of Sri Lanka. The weighted arithmetic index method has been used to calculate the water quality index. The water quality index of the study area was recorded as good (33.60760) in 2010 and poor in 2013 (56.95663), 2016 (52.37269), and 2019 (69.04417). The study revealed that the water temperature in the canal fluctuates with the time and climate of the area. The EC of the water is registered within the reference range. However, pH, COD, DO, and ammonia are the main water parameters deviating from the reference range. It is observed that the leading causes of the deterioration of water quality are human activities, the illegal discharge of sewage and industrial wastewater, the lack of adequate sanitation facilities, and urban runoff.

3

Wastewater treatment technologies

88%

Wilas J., Draszawka-Bołzan B., Daniszewski P., Cyraniak E.

World News of Natural Sciences

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2016

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vol. 4

33-43

EN

The article presents an application of multi-criteria analysis for selection of the best treatment technology and the best technical solution to the running of a large and a small wastewater treatment plant. The calculations performed for two plant capacities and for various effluent standards are based on a compromise programming method. The effluent standards considered for the smaller plant are only BOD5, COD and TSS, while for the larger plant also nitrogen and phosphorus. For each plant’s capacity, three different treatment technologies are analyzed. The analyzed technologies included biofilters, continuous and cyclic activated sludge, rotating biological contactors and natural treatment methods. The selection of the best technology is done with a define set of sustainability criteria that can be easily modified and adjusted to specific local conditions. The proposed method can be used for selection of the best treatment technology and the most appropriate technical solution from a sustainability standpoint, at the stage of wastewater system planning and designing, as well as for evaluation of already operating plants.

4

Assessment of surface water pollutant models of estuaries and coastal zone of Quang Ninh – Hai Phong using Spot-5 images

75%

Ke L. C., Trang H. T. V., Liem V. H., Tuong T. N., Duyen P. T.

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vol. 64

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issue 1

5

Coagulation and UF treatment of pulp and paper mill wastewater in comparison

75%

Simonič M., Vnučec D.

Open Chemistry

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2012

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vol. 10

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issue 1

127-136

EN

A study using coagulation-flocculation and ultrafiltration (UF)methods for pulp and paper mills’ wastewater (WW)was carried out. The reduction efficiencies of turbidity and chemical oxygen demand (COD), the removal efficiency of total suspended solids (TSS) and absorbance at 254 nm were the main evaluating parameters. Using coagulation-flocculation, the efficiencies of alum and polyaluminum chloride (PACl)were studied, when used alone and when coupled with flocculant aids. During the coagulation-flocculation process, use of a single coagulant, the coagulant dosage, and the pH, play an important role in determining the coagulation efficiency. At the optimum PACl dosage of 840 mg L−1 and optimum pH of 9.0, turbidity reduction was found to be 94.5%. A combination of inorganic coagulant and flocculant, or polymer was applied, in which PACl was used coupled with the polyelectrolytes Organopol WPB20 and WPB40. PACl coupled with Organopol WPB20 by optimal pH 9 gave a 98.3% reduction of turbidity, 91.9% removal of TSS, and a 60.2% reduction in COD. Ultrafiltration trials were carried out on a pilot scale. A tubular module was used with ceramic membrane. This membrane is a multi-channel membrane with an active surface layer made of Al2O3 and ZrO2. Within the acidic range, the turbidity and TSS were removed at above 99%.

6

Impact of Alkalization of Surplus Activated Sludge on Biogas Production

63%

Grűbel K., Machnicka A., Wacławek S.

Ecological Chemistry and Engineering S

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2013

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vol. 20

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issue 2

343-351

EN

Large amounts of sludge are produced in biological wastewater treatment plants. Since the sludge is highly contaminated, it has to undergo proper stabilization before it is disposed or utilized in an environmentally safe way. On the whole, the aim of bacterial cell disintegration is the release of cell contents in the form of an aqueous extract. Chemical disintegration of surplus activated sludge by alkalization results in destruction and disruption of the flocs and microorganisms as well as increase concentration of organic matter in supernatant. The mesophilic anaerobic sewage sludge digestion is an established process, most often applied at medium and large municipal sewage treatment plants. Four major steps of anaerobic digestion are distinguished. The first hydrolysis step leads to solubilization of insoluble particulate matter and biological decomposition of organic polymers to monomers or dimers. The hydrolysis step is recognized as the rate-limiting step of the following second and third steps, the processes of acidogenesis and acetogenesis. Chemical disintegration activates biological hydrolysis and, therefore, it can significantly increase the stabilization rate of the secondary sludge. It has been shown that when the activated sludge was subjected to alkalization to pH 9.0 value, the COD concentration increased from 101 to 530 mg/dm3 in sludge supernatant. The paper presents a potential application of chemical disintegration for sewage sludge (mainly activated sludge) to upgrading biogas production.

PL

Osady, powstające w procesie oczyszczania ścieków, poddaje się procesom przeróbki i unieszkodliwiania w celu zmniejszenia ich objętości oraz pozbawienia ich szkodliwego wpływu na środowisko. Fermentacja metanowa jest jedną z najczęściej stosowanych metod biodegradacji materii organicznej zawartej w osadach ściekowych. W ostatnich latach odnotować można duże zainteresowanie badaczy działaniami wspomagającymi proces stabilizacji beztlenowej. Największe zainteresowanie dotyczy intensyfikacji procesu produkcji biogazu na drodze dezintegracji głównie mechanicznej, np. z wykorzystaniem ultradźwięków, homogenizacji nożowej czy też dezintegracji hydrodynamicznej. Oprócz fizycznych metod dezintegracji istnieje możliwość wykorzystania do tego celu procesów chemicznych - zakwaszania lub alkalizacji. W pracy starano się wykazać i określić wpływ jednej z metod dezintegracji - alkalizacji - osadu czynnego na proces stabilizacji beztlenowej. Dodatek substancji alkalizującej, np. wodorotlenku sodu, do osadu czynnego powoduje destrukcję kłaczków osadu oraz zmiękczanie ścian komórkowych mikroorganizmów budujących osad czynny, co w konsekwencji prowadzi do ich lizy. Uwalniana w ten sposób materia organiczna stanowi szybko i łatwo rozkładalny produkt, który w znacznym stopniu przyspiesza pierwszą fazę procesu stabilizacji beztlenowej, tj. fazę hydrolityczną. Konsekwencją tego jest przyspieszenie i wydłużenia fazy metanogennej, dzięki czemu zwiększa się ilość wyprodukowanego biogazu. Na podstawie uzyskanych wyników można wnioskować, że dezintegracja alkaliczna bardzo dobrze nadaje się do wstępnego kondycjonowania osadów. Znacznie zwiększona ilość wyprodukowanego biogazu, jak również niska cena NaOH zachęca do korzystania z tego procesu jako wstępnego przygotowania osadów przed ich stabilizacją.

7

Beam divergence and COD issues in double barrier separate confinement heterostructure laser diodes

63%

Maląg A.

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2005

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vol. 53

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issue 2

Refine search results

Factors Affecting the Performance of Double Chamber Microbial Fuel Cell for Simultaneous Wastewater Treatment and Power Generation

An assessment of water quality temporal variation in Sri Jayawardenapura Kotte canal, Sri Lanka

Wastewater treatment technologies

Assessment of surface water pollutant models of estuaries and coastal zone of Quang Ninh – Hai Phong using Spot-5 images

Coagulation and UF treatment of pulp and paper mill wastewater in comparison

Impact of Alkalization of Surplus Activated Sludge on Biogas Production

Beam divergence and COD issues in double barrier separate confinement heterostructure laser diodes