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Modification of Electro-Fenton Process with Granular Activated Carbon for Phenol Degradation – Optimization by Response Surface Methodology

Thwaini Hind H., Salman Rasha H.

Journal of Ecological Engineering

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2023

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Vol. 24, nr 9

92--104

EN

As a result of rapid industrialization and population development, toxic chemicals have been introduced into water systems in recent decades. Because of its excellent efficiency and simple design, the three-dimensional (3D) electro-Fenton method has been used for the treatment of wastewater. The goal of the current study is to explore the efficiency of phenol removal by the 3D electro-Fenton process, which is one of the advanced oxidation processes (AOPs). In the present work, the effect of the addition of granular activated carbon (GAC) particles to the electro-Fenton system as the third electrode would be investigated in the presence of graphite as the anode and nickel foam as the cathode, which is the source of electro-generated hydrogen peroxide (H2O2). The influence of operation parameters (current density, electrolysis time, and GAC) on catalytic performance will be studied, which will be adjusted by the response surface methodology (RSM). The pH was adjusted to 3, and the airflow was set to 10 L/h. According to the results the nickel foam was an excellent cathode material choice. The best conditions for phenol elimination were at current density of 3.56 mA/cm2, FeSO4.7H2O dosage of 0.1 mM, GAC of 30 g, and a time of 3 h to attain the removal rates of phenol and chemical oxygen demand (COD) of 98.79% and 93.01%, respectively. The results showed that time had a higher effect on the phenol and COD removal efficiency, while the impact of current density was lower. The model equation’s high R2 value (97.90%) demonstrates its suitability.

2

Assessment of the ozonation impact on adsorption efficiency in surface water treatment

Adamski Wojciech, Wisniewski Jacek, Wolska Malgorzata

Environment Protection Engineering

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2023

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Vol. 49, nr 3

95--107

EN

Organic substances in water, both of natural and synthetic origin, especially their share in water treatment by-products can pose a threat to drinkers. That is why adsorption, as a very effective process of dissolved organic compounds removal is commonly used in surface water treatment systems. For process design and optimization, mathematical models both mechanistic and statistics are created. The results of the investigation of granular activated carbon (GAC) bed adsorption in a pilot plant with a capacity of 3 m3/h have been presented. Two systems have been tested – without ozonation and with ozonation before GAC adsorption. The models of the kinetics of GAC adsorption capacity exhaustion, the model of minimal GAC bed depth (adsorption zone) for assumed process efficiency (C/CO), as well as the model of adsorption zone movement velocity to the bottom of GAC bed, have been created. For the state of adsorptive equilibrium, the first model enables the determination of the isotherm parameters of the Freundlich type, the two other models are used for the calculation of GAC bed run time for the certain bed depth and assumed efficiency. It has been shown that in this case (water pollution, GAC type, pretreatment) ozonation plays a minor role.

3

Environmental Assessment of a Unique Filtration Process for Treatment of Polluted Storm Water

Al-Khalaf Safaa K. Hashim, Al-Ridah Zaid Abed, Shlash Marwah Abdullah, Naje Ahmed Samir

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 1

116--124

EN

As a result of poor human activities, storm water is now contaminated, notably in the Middle East. The filtering process is a physical separation with no chemical reactions occurring throughout the operation. The goal of this research is to use three distinct types of filters to improve the quality of storm water: sand, sand with granular activated carbon (GAC), and sand with cotton. Before and after treatment, the pH, turbidity, electric conductivity, TDS, and temperature of storm water are all monitored. In addition, the water quality index (WQI) was computed. The parameters of treated storm water varied depending on the filter media used, such as sand (turbidity = 83 NTU, TDS = 585 mg/L, conductivity = 1190 S/cm, pH = 7.1 and temperature =17.8 °C), sand with GAC (turbidity = 12NTU, TDS = 540 mg/L, conductivity = 910 S/cm, pH = 7 and temperature =18 °C) and sand with cotton (turbidity = 6.4 NTU, TDS = 490 mg/L, conductivity = 1090 μS/cm, pH = 7.2 and temperature =17.6 °C). Sand has a treatment efficiency of 63.6 percent, sand with GAC has an efficiency of 84.9 percent, and sand with cotton has an efficiency of 84.2 percent at a flow rate of 0.66 L/min, when WQI is clean. With GAC, it is clear that the dual media filter is the finest special sand.

4

Economic aspects of pretreatment technologies before reverse osmosis

Gumińska Jolanta, Kłos Marcin

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

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2020

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z. 145

119--131

EN

Purpose: The article presents the results of economic efficiency analysis for the construction of preliminary water purification systems before the membrane demineralization process. Two types of pre-treatment systems were analysed: conventional system and ultrafiltration. Design/methodology/approach: The profitability analysis of the construction of water pre-treatment systems (WPS) before membrane demineralization was carried out based on technological, economic and financial assumptions. Findings: The simulations allowed determining the boundary conditions for the profitability of this type of investment in the form of the adopted treatment technology, conditioned by the water pre-treatment method. The simulation results showed that with the current investment and operating costs of the combined rapid filtration process on three-layer beds and dynamic sorption and, alternatively, membrane pressure ultrafiltration, the choice of the latter pre-treatment method allows obtaining significantly better economic results. Originality/value: The results of the cost analysis of both tested variants indicate that the use of pressure ultrafiltration as the final process is much more effective than the conventional treatment system based on rapid filtration and dynamic sorption.

5

Pylenie domowych filtrów z węglem aktywnym

Dąbrowski Wojciech, Zielina Michał, Pulit Jolanta, Staroń Anita, Banach Marcin

Gaz, Woda i Technika Sanitarna

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2020

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Nr 6

14--18

PL

Przedstawiono trudności w pozytywnej ocenie stanu bakteriologicznego wody, uzdatnianej w procesie adsorpcji na granulowanym węglu aktywnym, w przypadku gdy ocena ta ma zawierać również całkowitą liczbę bakterii wyekstrahowanych z pyłu węglowego, przedostającego się do filtratu. Zgodnie z przeprowadzonym przeglądem literatury, zawartość mikroorganizmów w pyle węglowym w ostatnich latach skłoniła inżynierów japońskich do coraz częstszego projektowania filtrów piaskowych nie przed, ale po filtrach z granulowanym węglem aktywnym oraz tzw kanapkowych filtrów powolnych. Na podstawie obserwacji pracy filtrów z granulowanym węglem aktywnym, instalowanych w lodówkach, wyrażono pogląd, że one również wymagają zabezpieczenia przed pyleniem z węgla, w tym również w przypadku stosowania wkładów ze spiekanego węgla aktywnego. W konkluzji stwierdzono iż dla mikrobiologicznego bezpieczeństwa wody pitnej, cząstki pyłu węglowego powinny być usuwane z filtratu.

EN

Some difficulties with positive evaluation of bacteriological content of water treated using the process of adsorption on granular activated carbon have been stressed. The problem arises if the number of bacteria extracted from the coal dust particles is accounted. Some small coal particles are continuously releasing for the whole period of filters operation. According to the literature review in the last years the microorganisms content of coal fines caused Japanese engineers more often constructing sand filters not before, but after, GAC adsorbent filters and building sandwich slow filters. Based on own observations of filters applied in households to treating potable water it was suggested that the filtrate should be also protected against GAC particles. Laboratory tests confirmed that these filters also release coal fines even from the cartridge of agglomerated activated carbon. In conclusion it was suggested that for the drinking water microbiological safety the coal filters should be removed from the filtrate.

6

Zastosowanie szybkiego testu mikrokolumnowego do oceny wpływu naturalnych substancji organicznych na skuteczność usuwania zanieczyszczeń z wody na węglu aktywnym

Jodłowski A., Śmigielska K.

Ochrona Środowiska

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2007

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R. 29, nr 4

23-27

PL

Wykazano, że szybki adsorpcyjny test mikrokolumnowy umożliwia określenie właściwości adsorpcyjnych granulowanego węgla aktywnego poprzez pomiary prowadzone z użyciem złóż o ziarnach o małej średnicy przy dużych obciążeniach hydraulicznych w krótkim czasie. Wyniki uzyskane w wyniku przeprowadzenia testu umożliwiają przeniesienie skali w celu przewidywania działania filtrów sorpcyjnych w pełnej skali technicznej. Przedstawiono przykłady usuwania substancji organicznych pochodzenia naturalnego i antropogenicznego podczas oczyszczania wody do celów wodociągowych z wykorzystaniem sorpcji na granulowanym węglu aktywnym. Podano podstawy projektowania mikrokolumn, warunki prowadzenia testu oraz sposób interpretacji wyników uzyskanych podczas prac z wykorzystaniem kolumn wypełnionych świeżym węglem aktywnym oraz kolumn wypełnionych węglem o częściowo wyczerpanej zdolności sorpcyjnej.

EN

It has been demonstrated that the rapid small-scale column test (RSSCT) enables the sorptive properties of granular activated carbon (GAC) to be determined within a short time by measurements involving fine-grained beds and a high hydraulic load. The results of the RSSCT can be scaled up to predict the performance of GAC-filters under full-scale conditions. Examples are shown of the removal of organic matter (both natural and anthropogenic) during water treatment for the purpose of municipal supply, with sorption on a GAC bed as a unit process. The paper also specifies the design principles for the microcolumns, the testing conditions and the method of interpreting the test results obtained using columns packed with fresh or partly exhausted GAC.