Wyniki wyszukiwania - Biblioteka Nauki

1

Investigating activated sludge microbial population efficiency in heavy metals removal from compost leachate

100%

Farrokhi M. , Naimi-Joubani M. , Dargahi A. , Poursadeghiyan M. , Jamali H. A.

Polish Journal of Environmental Studies

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2018

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tom 27

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nr 2

EN

Solid waste production has increased in recent years. Many studies have shown that generated leachate from solid waste contains a high concentration of heavy metals. Their removal efficiency from leachate was investigated in aerobic suspended and attached growth systems in lab-scale within 72 hours of aeration. All of the materials used were analytical grade (Merck). Maximum efficiency of the attached growth system in removal of BOD₅ and COD was, respectively, 80% and 78.28%. Maximum removal efficiency for both attached and suspended growth was related to lead, and minimum removal efficiency was related to vanadium for the attached growth, and cadmium for suspended growth. Heavy metals removal efficiencies in attached growth from max to min were lead, iron, manganese, cobalt, zinc, mercury, magnesium, copper, chromium, nickel, cadmium, and vanadium, respectively; and the removal efficiencies for suspended growth from max to min were lead, manganese, iron, zinc, copper, magnesium, cobalt, mercury, chromium, nickel, vanadium, and cadmium, respectively. Generally it can be concluded that both systems are suitable for young leachate treatment, but to satisfy environmental discharge standards post treatment will be necessary.

2

An investigation and comparison of removing heavy metals (lead and chromium) from aqueous solutions using magnesium oxide nanoparticles

86%

Dargahi A. , Golestanifar H. , Darvishi P. , Karami A. , Hasan S. H. , Poormohammadi A. , Behzadnia A.

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nr 2

EN

This study aims to investigate the effi ciency of magnesium oxide nanoparticles (MON) in vitro for the removal of lead (II) and chromium (VI) from aqueous environments. The effects of various parameters such as contact time (15 to 280 min), pH (3, 5, 7 and 9), the initial concentration of lead/chromium (10, 20, 30.40 and 50 mg/L), absorbent dose (0.3, 0.5 and 0.8 g/L), and shaking speed (150 to 350 rpm) was investigated. The parameters were optimized by varying one parameter at a time and keeping other parameters constant. The maximum removal effi ciency of MON for lead (II) and chromium (VI) was achieved at contact time 280 min, pH 9, initial concentration of lead/chromium 10 mg/L, adsorbent dose 0.8 g/L, and shaking speed 250 rpm. The results also indicated that MON convert the Pb2+ to Pb0 and Cr6+ to Cr3+ during the removal process. The adsorption of lead (II) and chromium (VI) follows the Langmuir isotherms, therefore the adsorption was of a physical nature.

3

Survey on treatment ability of stabilization pond as a natural treatment system in oil refinery wastewaters

86%

Dargahi A. , Mohammadi M. , Karami A. , Amirian F. , Tabandeh L. , Almasi A.

Polish Journal of Environmental Studies

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2018

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tom 27

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nr 1

EN

An oil refinery is one industry that introduces large amounts of toxic phenol in receiving waters annually. Hence, the aim of this study was phenol removal from oil refinery wastewater by a natural treatment system of a stabilization pond. In this study, a pilot-scale pond volume, hydraulic load, and hydraulic retention time were 200 L, 40 L/day and five days, respectively. Influent concentration of phenol was 100-400 mg/L. Responses of the process were NH₃, PO₄, phenol, TCOD, SCOD, TBOD, SBOD, and pH. The results showed that increasing phenol concentration and decreasing temperature have negative effects on system efficiency. Maximum removal of NH₃, PO₄, phenol, TCOD, SCOD, TBOD, and SBOD were 61.08, 70.09, 93.58, 80.18, 78.89, 78.7, and 76.84% in high temperature, respectively. Maximum efficiency of wastewater treatment system was obtained in phenol concentration at 100 mg/L. Also, anaerobic stabilization ponds are cost-effective options with simple operation that can be employed for the treatment of phenol content of oil refinery wastewaters.

4

Residue analysis of pesticides, herbicides, and fungicides in various water sources using gas romatography-mass detection

86%

Samarghandi M. R. , Mohammadi M. , Karami A. , Tabandeh L. , Dargahi A. , Amirian F.

Polish Journal of Environmental Studies

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2017

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tom 26

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nr 5

EN

Pesticides along with with their degradation products spread throughout the environment and contaminate the water, leading to a consequent potential risk to humans and also the environment. The study aims to determinene the residual pesticides (organophosphorus, pyrethroids ), herbicides, and fungicides in the water resources (wells, deep wells, springs, spring-heads, and flumes) of Kermanshah Province, Iran. Water samples were taken from 50 stations from April to June 2016, and analyses were performed using gas-chromatography–mass-spectrometry techniques. Data were analysed using SPSS version 20. One of the most important points of this study is the fact that all water resources were safe except for deep wells. Total concentration of organophosphorus was 2.2 ppb. The mean concentration of pyrethroids in Islamabad Gharb and Songhor was 0.574 and 2.235 ppb, respectively. Organophosphorus and pyrethroid pesticides total concentration was more than the European standard. The contamination range of difenoconazole fungicide was 0.024 ppb (Gilan Gharb) and 1.089 ppb (Kermanshah). Glyphosate herbicide was only seen in Islamabad Gharb (0.011 ppb). The mean concentration of all pesticides in the investigated wells was more than the European standard. Estimating pesticide concentration is important for preserving aquatic ecosystems and human health.

5

Nitrogenous contamination in Iranian vegetables: a review

86%

Almasi A. , Mohammadi M. , Dargahi A. , Amirian F. , Motlagh Z. J. , Ahmadidoust G. , Noori M.

Polish Journal of Environmental Studies

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2018

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tom 27

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nr 6

EN

Vegetables are the main source of nitrate food contamination. More than 80% of nitrates are consumed by humans through vegetables. The present study was conducted to investigate the contamination of nitrite and nitrate vegetables in Iran. In this systematic overview we reviewed all internal and external databases for relevant articles. According to different studies, contamination was detected in different types of vegetables in different regions of Iran. Articles that examined nitrite values above the standard limit were not reported. Due to nitrate contamination in vegetables in some cities of Iran and the effects of this nitrogen combination on human health, it is necessary to find a solution in this regard.

6

Disinfecting poultry slaughterhouse wastewater using copper electrodes in the electrocoagulation process

58%

Zarei A. , Biglari H. , Mobini M. , Dargahi A. , Ebrahimzadeh G. , Narooie M. R. , Mehrizi E. A. , Yari A. R. , Mohammadi M. J. , Baneshi M. M. , Khosravi R. , Poursadeghiyan M.

Polish Journal of Environmental Studies

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2018

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tom 27

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nr 4

EN

Insufficiencies and deficiencies in slaughterhouses could adversely affect public health. Wastewater from slaughtering, along with high microbial pollution, results in serious pollution to the surrounding environment if not treated. This study sought to investigate the efficiency of the electrocoagulation process using copper electrodes in the disinfection of poultry slaughterhouse wastewater without any initial controlling. The physical and chemical properties of samples of wastewater taken from a poultry slaughterhouse were first analyzed. Then the samples were subjected to the electrocoagulation process using copper electrodes in potential differences of 10, 20, and 30 V over a period of 60 min. Then the removal efficiency of total coliforms was examined in accordance with standard methods found in textbooks. The results obtained from this study indicated that the efficiency of the electrocoagulation process increased by an increase in process time as well as in electric potential difference. The maximum removal efficiency of total coliforms was 100% in potential difference, equal to 30 V in the reaction time of 10 min. Moreover, the results of this study revealed that the electrocoagulation process using a copper electrode was fully able to remove total coliform from poultry slaughterhouse wastewater.

7

Enhancing electrocoagulation process efficiency using Astraglus gossypinus Tragacanth in turbidity removal from brackish water samples

58%

Zarei A. , Biglari H. , Mobini M. , Ebrahimzadeh G. , Yari A. R. , Narooie M. R. , Mehrizi E. A. , Dargahi A. , Baneshi M. M. , Mohammadi M. J. , Mazloomi S.

Polish Journal of Environmental Studies

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2018

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tom 27

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nr 4

EN

Colloidal particles are the main cause of turbidity in an aquatic environment. Water turbidity maintains pathogenic microorganisms against disinfection. In addition to increasing the consumption of antiseptic substances, mainly it causes a lot of aesthetic and non-sanitary problems such as the formation of toxic and carcinogenic side constituents in the treatment of water. In this study we investigated the efficiency of the use of tragacanth of Astraglus gossypinus (Catira) on the effectiveness of the electrocoagulation process in the removal of turbidity from brackish water. In this descriptive-analytic study, direct bentonite injections of 2 to 8 g/L were used to provide opacity. In the following, the effect of applying coagulant aid of Tragacanth of Astraglus gossypinus plant with values of 0.25 to 1.5 g/L on the efficiency of the electro-coagulation process equipped with iron electrodes in the removal of opacity from brackish water samples were examined in potential difference from 5 to 30 volts, and pH from 2 to 9 over a period of 60 min. Variation of turbidity was determined using the turbidity sensor in accordance with standard reference methods. The results showed that the highest opacity removal efficiency is about 99% for each 1 kg of opacity due to the addition of 7 g/L bentonite under neutral pH conditions, Tragacanth dose of 1.5 g/L, 8 g/L dose of NaCl, and voltage of 30 V for 30 min, along with the average consumption of iron and electrical energy of 0.18 kg and 0.53 Kwh, respectively. Thus, the use of Astraglus gossypinus tragacanth for removing turbidity as a natural coagulant aid dramatically improves the electrocoagulation process efficiency in the removal of turbidity from brackish water samples and reduces current costs of the electro-coagulation process.