Wyniki wyszukiwania - Biblioteka Nauki

1

Optimization of electrocoagulation of instant coffee production wastewater using the response surface methodology

100%

Bui H. M.

Polish Journal of Chemical Technology

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2017

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tom Vol. 19, nr 2

67--71

EN

The COD removal efficiency from an instant coffee processing wastewater using electrocoagulation was investigated. For this purpose, the response surface methodology was employed, using central composing design to optimize three of the most important operating variables, i.e., electrolysis time, current density and initial pH. The results based upon statistical analysis showed that the quadratic models for COD removal were significant at very low probability value (<0.0001) and high coefficient of determination (R2 = 0.9621) value. The statistical results also indicated that all the three variables and the interaction between initial pH and electrolysis time were significant on COD abatement. The maximum predicted COD removal using the response function reached 93.3% with electrolysis time of 10 min, current density of 108.3 A/m2 and initial pH of 7.0, respectively. The removal efficiency value was agreed well with the experimental value of COD removal (90.4%) under the optimum conditions.

2

Comparison of effectiveness of electrocautery and phenol application in partial matricectomy after partial nail extraction in the treatment of ingrown nails

100%

Misiak P. , Terlecki A. , Rzepkowska -Misiak B. , Wcisło S. , Brocki M.

Polish Journal of Surgery

|

2015

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tom 86

|

nr 2

89-93

EN

Ingrowing nail also known as onychocryptosis is a common health problem. This disease mostly affects young people, often carrying a considerable amount of socio-economic implications. It’s foot problem that usually manifests as inflammation of tissue along the side of a toenail. The aim of the study was to asses and to compare effectiveness of electrocautery and phenol application in partial matrixectomy after partial nail extraction in the treatment of ingrown toenails. Material and methods. The group of 60 patients with ingrowing toenail which was randomized into two groups underwent partial matrixectomy in surgical outpatient clinic between 2009-2013. This group of patients was under surgical observation for 100 days in outpatient clinic. Results. In all operated patients we obtained surgical success however we had 13 recurrences during the follow up period, 5 in the phenolization group and 8 in the electrocoagulation group. Conclusions. There was statistically significant difference between these two techniques, which indicated that matrix phenolization is connected with shortened healing time vs the matrix electrocoagulation.

3

Removal of Escherichia coli from Domestic Wastewater Using Electrocoagulation

100%

Aguilar-Ascon E.

Journal of Ecological Engineering

|

2019

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tom Vol. 20, nr 5

42--51

EN

The objective of this study was to evaluate the efficiency of electrocoagulation in the removal of Escherichia coli from domestic and urban wastewaters and to determine the effects of the main operational parameters on the process. An electrocoagulation reactor with aluminum and iron electrodes was built for this purpose. A factorial design was applied, where amperage, treatment time, and pH were considered as the factors and E. coli percent removal was the response variable. After 20 min of treatment, >97% removal efficiency was achieved. The highest E. coli removal efficiency achieved was 99.9% at a neutral pH of 7, amperage of 3 A, and treatment time of 60 min. However, the removal efficiency of close to 99% was also achieved at natural wastewater pH of 8.5. The statistical analyses showed that the three tested factors significantly affected the E. coli removal percentage (p < 0.05). These results indicate that electrocoagulation has a high disinfection power in a primary reactor in removing water contaminants as well as simultaneously removing pathogenic microorganisms when compared to biological treatment processes. This represents an additional benefit, because it will considerably reduce the use of chlorine during the final disinfection stage.

4

Ciprofloxacin Removing from Aqueous Solutions Using Batch Reactor Electrocoagulation Process with Aluminum Electrodes

100%

Majid R. , Samaka I. a. S.

Journal of Ecological Engineering

|

2023

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tom Vol. 24, nr 9

364--372

EN

Increasing the reliance on pharmaceuticals such as analgesics, antibiotics, antidepressants, and other medications harms the environment and human health. The electrocoagulation process is a modern and crucial technology for treating various pollutants. This paper uses electrocoagulation technology (EC) to remove the most widely used antibiotic, ciprofloxacin (CIP) from an aqueous solution. The proposed approach was experimentally implemented in a batch reactor equipped with (aluminium sheets) that act as electrodes (cathode and anode) arranged vertically in a monopolar parallel mode (MP-P). Different operating parameters were considered, in this work, including inter-electrode distance (IED), pH of the solution, current density (CD), electrolysis time (ET), initial concentration of CIP (Co), and concentration of supporting electrolyte NaCl. Several experiments were performed, and the results revealed that EC has successfully applied with a high removal efficiency of 98.48% under optimum operating conditions: a gap between electrodes = 1 cm, current density = 1.5 mA/cm2, electrolysis time = 60 min, pH = 5, initial CIP concentration = 50 mg/l, and NaCl = 500 mg/l. The experimental results confirmed that the EC process provides a strategy for removing CIP from wastewater with a high removal efficacy and low energy consumption, additionally offering an increased opportunity for using Al-EC cells to treat antibiotic contaminants.

5

The Treatment of Hospital Wastewater Using Electrocoagulation Process – Analysis by Response Surface Methodology

100%

Salah Al-Shati A. , Alabboodi K. O. , Shamkhi H. A. , Abd Z. N. , Emeen S. I. M.

Journal of Ecological Engineering

|

2023

|

tom Vol. 24, nr 1

260--276

EN

Electrocoagulation (EC) can be defined a method utilized to remove pollutants from wastewater by applying an electric current to sacrificial electrodes. Many experimental variables like NaCl content (0–4 g/l), current density (5–25 mA/cm2), time (30–90 mins), and pH (4–10) that influence the removal efficiency regarding COD were considered. In the presented research, three distinct configurations related to electrodes, i.e. Al-Al, Fe-Al, and Fe-Fe, have been utilized to determine which was the most effective. RSM depending on BBD was utilized for optimizing various operational parameters with regard to HWW by use of EC. Maximum COD removal (97.9%) was reached at Fe-Al electrodes, NaCl (3.2 g/l), current density (24.7 mA/cm2), time (81.7 mins), and pH (7.4). COD removal (91.3%) was achieved at the Al-Al electrodes, NaCl (3.8 g/l), current density(23.5 mA/cm2), time-86.3 min, and Ph (7.7). At the Fe-Fe electrodes, the removal of COD (89.5%) was obtained at NaCl (2.3 g/l), current density (24.6 mA/cm2), pH 8.5, and time (86.9 min). This indicates that EC could remove pollutants from different types of wastewaters under many operating parameters and with arrangements of electrodes.

6

Comparison of Lateral Thermal Spread Using Monopolar and Bipolar Diathermy, and the Bipolar Vessel Sealing System ThermoStapler™ During Thyroidectomy

100%

Brzeziński J. , Kałużna-Markowska K. , Naze M. , Stróżyk G. , Dedecjus M.

Polish Journal of Surgery

|

2011

|

tom 83

|

nr 7

355-360

EN

Electric devices enabling the maintenance of haemostasis during surgery have found application in modern thyroidectomy procedures. The haemostatic effect is associated with generation of heat, which apart from the intended result may bring about thermal tissue injury.The aim of the study was to determine the thermal spread around the active tip of electric devices in the operating field during total thyroidectomy, and the safe temperature range during the operation of studied devices.Materials and methods. Over 14 months from December 2009 until January 2011, 76 total thyroidectomy procedures were analysed. The surgeries employed mono- and bipolar diathermy as well as the ThermoStapler™ bipolar vessel sealing system. During the procedures, the thermal spread around the active tips of used electric devices was recorded with the use of high-definition camera. Comparable 5-second periods of electric device use at two power ranges (30 W and 50 W) were selected from the recorded material. The highest temperature of the active tip of electric devices was determined, and the 42°C isotherm was found with the use of computer image analysis, thus determining the safe distance of important anatomic structures from the active tip of the electric device.Results. The temperature spread around the active tips of electric devices was recorded and the 42°C isotherm was determined. The diameter of this isotherm at the end of operation differed statistically significantly depending on the type of electric devices and power settings. The highest temperature, at both power ranges, was recorded for the bipolar vessel sealing system, while the lowest - for bipolar diathermy; at the same time a significantly lower 42°C isotherm diameter was found for ThermoStapler™ as compared with other devices. In all studied cases, the largest heat spread was found for monopolar diathermy.Conclusions. The mean safe distance of the active tip of an electric device from important anatomic structures is 5 mm and depends on the device type and its power settings. Monopolar diathermy causes the strongest heating of surrounding tissues, and the ThermoStapler™ bipolar vessel sealing system, despite producing the highest temperature during operation, causes relatively small thermal injury to the surrounding tissues.

7

Electrocoagulation of pulp and paper wastewater in a recirculation system

100%

Smoczynski L. , Zaleska-Chrost B.

Polish Journal of Natural Sciences

|

2002

|

tom 12

8

An investigation of the effect of NaCl concentration on the electrocoagulation of coal preparation plant tailings

88%

Eskibalci M. F. , Ozkan M. F.

Physicochemical Problems of Mineral Processing

|

2018

|

tom Vol. 54, iss. 3

934--943

EN

Coal preparation is the process of separating the coal from mineral impurities to produce high-grade coal, and the wastewater of the coal separation process is mainly consisted of fine coal and clay particles. Electrocoagulation (EC) is one of the effective methods for wastewater treatment. In this context, this study was aimed to investigate the evaluation of EC process for coal preparation plant wastewaters. Several key parameters affecting the efficiency of EC were investigated with laboratory scale experiments in search of optimal parameter values. Most importantly, the effect of NaCl concentration on the precipitation of coal preparation plant tailings by EC was investigated. Current density, electrolysis time, mixing speed, mixing time, pH, and salt concentration were studied using an aluminum electrode. Based on the results obtained from this study, the optimum conditions were found to be as pH 7.88 (natural pH), current density 40 (A/m2), mixing speed 360 rpm, premixing time 120 sec, and electrolysis time 300 sec. Under the optimum operating conditions, the results indicated that EC can be successfully applied for the coal preparation wastewaters, and the turbidity was reduced from 1260 NTU to 63 NTU (95% efficiency) with an operating cost of $5.67/Mg of tailings. By the increasing the salt content, a small increase in the turbidity was observed with a decrease in the voltage. With only a 1% decrease in the removal efficiency, the cost was reduced to $3.19/Mg with a 44% operating cost reduction.

9

Reduction of Total Chromium Levels from Raw Tannery Wastewater via Electrocoagulation using Response Surface Methodology

88%

Aguilar-Ascón E. , Marrufo-Saldaña L. , Neyra-Ascón W.

Journal of Ecological Engineering

|

2019

|

tom Vol. 20, nr 11

217--224

EN

This study focused on reducing total chromium levels in raw wastewater from the leather tanning industry via electrocoagulation to comply with maximum permissible limits (MPL) and to determine the effects of main process parameters. An electrocoagulation reactor was built using aluminum electrodes as an anode and cathode. Then, the response surface methodology was applied using a 3k factorial design considering three factors, namely current intensity, treatment time, and pH. The total chromium removal percentage was considered as a response variable. 99% of the total chromium found in wastewater could be removed after 14-min treatment at 2-A current intensity and pH 5.5. Similar amount of chromium was removed at pH of 8.5 and 7. Statistical analysis performed at a confidence level of p < 0.05 revealed that all three factors influenced electrocoagulation. Total chromium could be efficiently removed from raw wastewater at a current intensity of 2.9 A, a pH of 8.4, and a treatment time of 21 min, suggesting that electrocoagulation using aluminum electrodes is an efficient method for total chromium removal. Thus, this process must be considered as a solution to the problems caused by the leather tanning industry and for better compliance with the MPL established in the Peruvian environmental standards.

10

Removal of Nitrogen and Phosphorus from Domestic Wastewater by Electrocoagulation: Application of Multilevel Factorial Design

88%

Aguilar-Ascon E.

Journal of Ecological Engineering

|

2020

|

tom Vol. 21, nr 7

124--133

EN

The main objective of this investigation was to evaluate the efficiency of electrocoagulation in eliminating nitrogen and phosphorous from domestic wastewater and to determine the main operating parameters affecting the process. Accordingly, an acrylic reactor and aluminum (cathode) and iron (anode) electrodes were used. The tests were performed based on a multilevel factorial experimental design, considering current intensity, treatment time, and pH as factors. The design response variables were the percentage of nitrogen and phosphorous removal. In the case of phosphorus, the removal rates of up to 99% were reached after 40 minutes of treatment with current intensities of 3 amps and at a modified pH of 6. The nitrogen removal was up to 27% with a treatment time of 40 minutes, 3 amps, and a pH of 6. A statistical analysis revealed that pH did not have a significant effect on the nitrogen removal process, whereas in the phosphorus removal, the three factors influenced the process at a confidence level of 0.05. The results indicate that the electrocoagulation process in this type of water is very efficient in the removal of phosphorus, whereas for nitrogen, the efficiency decreases noticeably. However, electrocoagulation has an advantage over other conventional treatment technologies, because it does not require additional treatment units to remove phosphorus.

11

The Performance of Electrocoagulation Process in Removing Organic and Nitrogenous Compounds from Landfill Leachate in a Three-Compartment Reactor

88%

Bagastyo A. Y. , Sidik F. , Anggrainy A. D. , Lin J.-L. , Nurhayati E.

Journal of Ecological Engineering

|

2022

|

tom Vol. 23, nr 2

235--245

EN

In this study, the effectiveness of the electrocoagulation (EC) process was evaluated based on the reduction of organic and nitrogenous contaminants in landfill leachate. A three-compartment electrochemical reactor as pre-treatment of stabilized landfill leachate was carried out ahead of biological treatment. The removal efficiencies of COD, BOD, ammonia, and nitrate were analyzed at pH 4, 6, and 8 with the current densities of 20.83 and 29.17 mA•cm–2. At pH 4, the highest removal of COD and NH4+ was obtained, i.e., in the range of 72–81% and 43–59%, respectively. The ratio of BOD5/COD was increased after EC, from initially 0.11 to 0.32 at pH 4. In addition, EC effectively removed humic substances in the leachate by targeting a large amount of high molecular weight humic substances, with around 103 kDa. However, the higher removal efficiency observed at higher current density leads to higher specific energy consumption. At a current density of 29.17 mA•cm–2, the specific energy consumption obtained in EC was around 10–17 Wh•g–1 COD and 99–148 Wh•g–1 NH4+. This could be decreased up to 50% at an applied current density of 20.83 mA•cm–2 with slightly lower efficiencies.

12

Treatment and utilization of the concentrate from membrane separation processes of landfill leachates

88%

Nowak R. , Włodarczyk-Makuła M.

Civil and Environmental Engineering Reports

|

2020

|

tom Vol. 30, no. 2

92--104

EN

The purpose of the paper was to assess the effectiveness of selected physico-chemical processes to improve the quality of retentates/concentrates obtained during the treatment of landfill leachates using membrane separation. Among the physico-chemical methods, Advanced Oxidation Process (AOP) and electrocoagulation were analysed. Landfill leachate resulting from the infiltration of waste mass by atmospheric precipitation as well as the dissolution and leaching of waste components are most often subjected to membrane separation. Permeate is usually discharged to the receiver, while the concentrate is recirculated and sprinkled on a waste pile. However, such action is only the retention of impurities in the body of the landfill and has an impact on the chemistry of raw leachates. Due to the very high concentrations of organic and inorganic compounds identified in the retentate, it is necessary to treat it, which will effectively reduce the amount of impurities in the leachate. Economic use seems to be another solution. An example would be growing energy crops but such application requires additional research.

13

Economic Valuation and Effectiveness of Utilizing Electrocoagulation System in Reducing Chemical Oxygen Demand of Textile Industry Wastewater

88%

Fikri E. , Sintawati N. , Ruhmawati T.

Journal of Ecological Engineering

|

2019

|

tom Vol. 20, nr 8

35--43

EN

Industrial activities vary greatly. The textile industry processes produce solid and liquid waste. The liquid waste comes from the process of reviewing threads, removing lubricants from synthetic fibers before weaving, and from the dyeing process. The purpose of this research is to determine the economic valuation and effectiveness of utilizing an electrocoagulation system in reducing Chemical Oxygen Demand (COD) of the textile industry wastewater. This research is a kind of an experimental study involving the pretest and posttest without control design. The research strategy consisted in 9 volt voltage and 5A electric current density with a 3 cm electrode plate distance. The container used in electrocoagulation process was made of plastic with the dimensions of 48.5×27.5×31 cm. The sampling technique was grab sampling with 3 treatments and 6 repetitions. The sample size was 45 liters. The results of this research indicate that the electrocoagulation method can reduce the level of Chemical Oxygen Demand (COD) in the textile production wastewater. The COD level before treatment was 221.5 mg/l, after electrocoagulation with 8 electrode plates dropped to 23.0–41.0 mg/l (85.26% decrease). The economic effectiveness and efficiency of the use of electrocoagulation compared to using conventional method in reducing COD level is only Rp 47.59/liter, while the conventional method reaches Rp 117.089/liter.

14

Treatment of Surface Treatment Effluents by Electrocoagulation Process Using Aluminium Electrodes

88%

Namoussi S. , Merbouh C. , Kabriti M. , Nahli A. , Naamane A. , Chlaida M. , Iounes N.

Journal of Ecological Engineering

|

2022

|

tom Vol. 23, nr 1

91--99

EN

The surface treatment industry generates effluents with a high load of highly toxic chemicals which must be treated under increasingly stringent regulation. The aim of this study was to treat the effluents of surface treatment unit of an aeronautical industry by the electrocoagulation process using aluminium electrodes. This process is used to study the performance to remove colloidal load, significant amount of oxidizable material and high levels of various metal elements (Cr, Fe, Zn, Cu and Al) from these effluents, under optimum conditions of pH 7, 8.6A of current intensity and 60 min of application. The electrocoagulation process was found to be effective in reducing turbidity (97.12%), COD (97.5%), SS (97.84%) and conductivity (96.82%), hexavalent chromium (99.99%), Zn (96.82%), Cu (94.3%), Iron (99.9%), Al (91.96%). The treated effluent conformed to the Moroccan standards of surface treatment discharge.

15

Porównanie efektów usuwania ortofosforanów ze ścieków metodą elektrokoagulacji i metodą roztwarzania metali

75%

Wysocka I. , Giza M. N.

Rocznik Ochrona Środowiska

|

2011

|

tom Tom 13

1915-1925

PL

Celem niniejszych badań było porównanie efektów usuwania związków fosforu (ortofosforanów) z wód z dodatkiem ortofosforanów, z wykorzystaniem dwóch metod: metody elektrokoagulacji (z wykorzystaniem procesów elektrochemicznych z użyciem prądu stałego) i metody roztwarzania metali (z wykorzystaniem procesów korozyjnych).

EN

There is a search in progress for some efficient methods of removing biogenic compounds from the treated sewage. Unquestionably, effective methods of phosphorus compounds removal include precipitation methods. The most common is the chemical precipitation method based on applying iron, aluminium or calcium salt to the solution and electrocoagulation. These methods utilise low solubility of metal phosphates and their sorption on the surfaces of the forming agglomerates. The real mechanism is quite complicated and consists of transforming phosphorus compounds into insoluble forms, and then separating them from the sewage by flotation, sedimentation, filtration. The method of iron solution should also be accounted into similar physical and chemical methods. The main difference between the aforementioned methods lies in the way of applying the precipitation agent to the solution. The method of iron solution is based on similar premises as the electrocoagulation method, however, metal ions here are dissolved into the solution as a result of spontaneous corrosion processes and, due to the further transformations in the sewage environment, they are to be responsible for phosphorus removal. The article presents comparative tests on a laboratory scale. The electrocoagulation method and metal digestion method were compared with regard to the effectiveness of orthophosphates removal from synthetic sewage. The comparison of both methods suggests that they can bring similar results of removing phosphorus (ortophosphates) from sewage. The process of reduction of concentration of orthophosphates in sewage occurs faster when the electrocoagulation method is used. However, with a longer test duration, better results are achieved using the metal digestion method. It was also noted that both methods introduce different amounts of iron into the solution. The methods differ with regard to the amount of iron remaining in the sewage in a suspended form. This indicates a better use of iron ions in the metal digestion method and it slightly limits the problem of an excessive amount of sludge.

16

Electrochemical Purification of Oil-Containing Shipping Waters

75%

Vozniuk M. , Shabliy T. , Gomelya M. , Sirenko L. , Sidorov D.

Journal of Ecological Engineering

|

2023

|

tom Vol. 24, nr 7

246--253

EN

The article describes the modern problems of formation and purification of marine oil-containing waters. The efficiency of using electrocoagulation to remove oil from water-oil emulsions of different mineralization using aluminum and iron anodes was studied. Treatment of water-oil solutions with an oil content of 100 mg/dm3 by electrocoagulation in a single-chamber electrolyzer provides 98–99% oil removal using these electrodes at an anode current density of 0.57–2.11 A/dm2 for highly mineralized waters and 0.34 A/dm2 for freshwater treatment during the first 15 minutes provides a reduction in oil concentration from 100 mg/dm3 to values at the level of 1.55–2.93 mg/dm3. When the water treatment time is extended to 45 minutes, greater efficiency in highly mineralized waters is provided by the aluminum anode.

17

Usuwanie sulfonamidów ze ścieków metodą elektrokoagulacji

75%

Baran W. , Zawora D. , Adamek E. , Makowski A. , Sobczak A.

Proceedings of ECOpole

|

2011

|

tom Vol. 5, No. 2

479--485

PL

Celem pracy było zbadanie możliwości usuwania sulfonamidów ze ścieków za pomocą procesów koagulacji chemicznej i elektrochemicznej. Zamierzano również optymalizować proces elektrokoagulacji ze względu na usuwania sulfonamidów. W trakcie badań stosowano próbki rzeczywistych ścieków komunalnych aplikowanych mieszaniną sulfadiazyny, sulfanilamidu, sulfametoksazolu i sulfatiazolu o stężeniach od 1 do 10 mg/dm3. Jako koagulant chemiczny stosowano wyłącznie roztwór FeCl3. Skuteczności koagulacji wyznaczano na podstawie obniżenia mętności ścieków oraz stopnia usunięcia wybranych do badań sulfonamidów. Porównano efekty uzyskiwane metodą koagulacji chemicznej i elektrokoagulacji oraz określono w szerokim zakresie wpływ pH i zastosowanej dawki koagulantu. W przypadku elektrokoagulacji określono dodatkowo wpływ rodzaju zastosowanej anody, gęstości prądowej, czasu trwania elektrolizy, natężenia prądu oraz wyjściowego stężenia sulfonamidów. W trakcie badań określono również wydajność prądową procesu. Stwierdzono, że zarówno klasyczna koagulacja chemiczna, jak i elektrokoagulacja są mało efektywnymi metodami usuwania sulfonamidów ze ścieków. W przypadku elektrokoagulacji można uzyskać nieznaczne zwiększenie usunięcia sulfonamidów, obniżając natężenie prądu i przedłużając czas trwania elektrolizy. Stwierdzono również, że proces usuwania sulfonamidów ze ścieków zachodzi bardziej efektywnie z użyciem anody wykonanej z żelaza niż z glinu. Ponadto konieczne jest każdorazowe eksperymentalne ustalanie optymalnej wartości pH roztworu poddawanego elektrokoagulacji.

EN

The aim of this study was to evaluate the possibility of removal of sulfonamides from wastewater using chemical and electrochemical coagulation processes. It was also intended to optimize the process of electrocoagulation from the viewpoint of sulfonamides removal. In the experiments, mixtures of sulfadiazine, sulfanilamide, sulfamethoxazole and sulfathiazole at concentrations from 1 to 10 mg/dm3 were added to real wastewater. FeCl3 solution was used as a chemical coagulant. Effectiveness of coagulation was determined based on the reduction in turbidity of wastewater and the degree of removal of selected sulfonamides. Moreover, the effects obtained by chemical coagulation and electrocoagulation were compared and effect of a wide range of pH and applied coagulant dose were determined. In the case of electrocoagulation the specific additional effect, such as the type of anode used, current density and intensity, time of electrolysis, and the initial concentration of sulfonamide were determined. In these experiments, the current efficiency of the process was also estimated. It was found that both the classical, chemical coagulation and electrocoagulation are low effective methods for the removal of sulfonamides from wastewater. In the case of electrocoagulation, a slight increase in the removal of Usuwanie sulfonamidów ze ścieków metodą elektrokoagulacji 485 drugs can be obtained by reducing current intensity and prolonging the time of electrolysis. The sulfonamides removal from wastewater occurred more efficiently with the use of iron than aluminum anode. Moreover, the experimental determination of the optimal pH in solution before electrocoagulation process was necessary each time.

18

Electrochemical treatment of model wastewater

75%

Smoczyński L. , Kalinowski S. , Zaborowska A.

Chemia i Inżynieria Ekologiczna

|

2004

|

tom Vol. 11, nr 12

1345--1354

EN

The results of electrochemical treatment of model wastewater ate presented and compared. A sixelectrode (three cathodes and three anodes) electrolyzer with aluminum or iron electrodes, enabling optimum contact between the electrode surface and flowing wastewater, was applied in a recirculation system. The determinations of chemical oxygen demand (COD), suspended solids concentration, turbidity and color intensity show satisfactory treatability of model wastewater by electrocoagulation. It was found that iron electrodes are characterized by lower electric energy consumption than aluminum ones. A similar number of Al3+ and Fe3+ moles was needed to eliminate a similar pollutant load, which indicates that the mass of the optimum dose of an iron electrocoagulant is twice higher than the mass of the optimum dose of an aluminum electrocoagulant.

PL

W niniejszej pracy zestawiono i porównano wyniki elektrochemicznego oczyszczania ścieków modelowych. W układzie recyrkulacyjnym stosowano 6-elektrodowy (3 katody i 3 anody) elektrolizer z elektrodami aluminiowymi bądź żelaznymi, zapewniający bardzo dobry kontakt pomiędzy powierzchnią elektrod a przepływającymi ściekami. W rezultacie oznaczeń ChZT, mętności, zawiesin i barwy stwierdzono satysfakcjonującą podatność badanych ścieków modelowych na elektrokoagulację. Ustalono, że elektrody żelazne zapewniają mniejsze zużycie energii elektrycznej aniżeli aluminiowe. Zbliżone liczby moli Al3+ i Fe3+ usuwały podobne ilości zanieczyszczeń, umożliwiając stwierdzenie, że masa optymalnej dawki elektrokoagulantu żelazowego jest niemal dwukrotnie większa niż masa elektrokoagulantu glinowego.

19

Treatment of Wastewater from the Pulp and Paper Industry by Electrocoagulation in a Static System

75%

Załęska-Chróst B. , Smoczyński L. , Wardzyńska R.

Ecological Chemistry and Engineering. A

|

2011

|

tom Vol. 18, nr 7

911-922

EN

Results of the electrochemical treatment of pulp and paper wastewater have been described. The electrolysis was conducted in static system on aluminium electrodes. The wastewater purification was carried out at two values of the current density 3.125 mA/cm2 and 6.25 mA/cm2. After electrocoagulation the COD, turbidity, suspended solids and color of the supernatant were measured. The fractal dimension of the aggregates-flocs of the sludge obtained was determined, too. The examined process of statical electrocoagulation turned out to be an efficient method for pulp and paper wastewater purification. The aggregates-flocs measured were recognized as self-simil objects.

PL

W niniejszej pracy przedstawiono wyniki elektrochemicznego oczyszczania ścieków celulozowo- -papierniczych. Elektrolizę prowadzono w układzie statycznym, z użyciem elektrod glinowych. Badania prowadzono przy dwóch wartościach gęstości prądu na elektrodach 3,125 mA/cm2 i 6,25 mA/cm2. Po elektrokoagulacji i sedymentacji mierzono w roztworze ChZT, mętnosć, barwę oraz zawiesiny. Jednoczesnie określono właściwości fraktalne otrzymanych agregatów-kłaczków osadu ściekowego i oznaczono ich rozmiary fraktalne. Badany proces elektrokoagulacji okazał się skuteczną metodą oczyszczania ścieków celulozowo-papierniczych. Badane agregaty-kłaczki były obiektami „samopodobnymi”.

20

Effect of Electrical Current and the External Source of Carbon on the Characteristics of Sludge from the Sequencing Batch Biofilm Reactors

75%

Kłodowska I. , Rodziewicz J. , Janczukowicz W.

Journal of Ecological Engineering

|

2018

|

tom Vol. 19, nr 4

143--152

EN

This work presents the results of an experiment on the effect of electrical current density (53, 105, 158 and 210 mA/m2), the type of an external source of carbon (citric acid, potassium bicarbonate) and C/NNO3 ratio (0.5, 1.0 and 1.5) on the quantity and quality of formed sludge. The experiment was conducted in sequencing batch biofilm reactors (SBBRs), under anaerobic conditions, with and without the passage of electrical current, under controlled pH of 7.5–8.0. The study demonstrated that in the reactors with electrical current passage and external source of carbon, the volume of sludge increased along with the current density increase from 53 to 158 mA/m2. At its highest density (210 mA/m2), the concentration of sludge was insignificantly lower. For all densities of electrical current and C/NNO3 values, the concentrations of sludge formed in the reactors with potassium bicarbonate (1.00 to 1.26 g d. m./L) were lower than in the reactors with citric acid (1.26 to 1.30 g d. m./L). The concentration of organic matter was higher in the sludge from the reactors with electrical current passage and potassium bicarbonate, compared to the sludge from the reactors with citric acid. In the reactors with electrical current passage and external source of carbon, the total nitrogen content in the sludge decreased along with the C/NNO3 ratio increase for current densities of 53 and 105 mA/m2. For a higher electrical current density, the nitrogen content in the sludge was similar. Irrespectively of the current density, the nitrogen content in the sludge from the reactors with citric acid was higher than in the sludge from the reactors with potassium bicarbonate. For higher current densities (158 and 210 mA/m2) the increase in the C/NNO3 value caused an increase in the P content in the sludge. The electrical current density increase contributed to increasing the content of phosphorus in the sludge. The phosphorus content in the sludge from the reactors with citric acid was lower than in the sludge from the reactors with potassium bicarbonate. The CST values prove that the sludge formed during the wastewater treatment in electrobiological SBBR was characterized by very high dewaterability. The capillary suction time decreased along with increasing the electrical current density but was not significantly affected by the type of carbon source.