Health and environment
Mohammad Hasan Kowsari; MohammadHossein Saghi; ayoob rastegar; Somayeh Sotude
Volume 29, Issue 1 , May and June 2022, , Pages 65-76
Abstract
Background: Even in engineered landfills in developed countries, leachate production cannot be avoided and it contains different types of heavy metals. Therefore, landfills are one of the main sources of increased concentrations of heavy metals in the soil. The purpose of this study was to evaluate the ...
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Background: Even in engineered landfills in developed countries, leachate production cannot be avoided and it contains different types of heavy metals. Therefore, landfills are one of the main sources of increased concentrations of heavy metals in the soil. The purpose of this study was to evaluate the severity of contamination of soils around Sabzevar landfill with heavy metals and to prepare a soil contamination map with heavy metals.Methods: Samples of surface and deep soils were collected in 18 stations according to the type of soil and distance from landfill Sabzevar. The concentrations of heavy metals Arsenic, Zinc, Lead, Chromium, Copper, Mercury and Cadmium were analyzed by ICP-OES. The intensity of soil contamination was assessed using Index Geoaccumulation Potential ecological risk index.Results: The mean concentrations of Arsenic, Zinc, Lead, Chromium and Copper in surface soil, respectively are, 6.013, 41.04, 6.31, 26.77 and 31.45 mg/kg of Mercury and Cadmium, respectively, 60.79 and 61.60 μg/kg, respectively. But the mean concentration of Arsenic, Zinc, Lead, Chromium and Copper in depth soil, respectively are, 5.75, 38.33, 6.25, 22.68 and 31.04 mg/kg, Mercury and Cadmium, respectively, 66.57 and 59.98 μg/kg, the value of all proportion to Natural background values are higher.Conclusion: Based on estimates of Igeo and RI indices for heavy metals Arsenic, Lead, Zinc, Chromium and Copper in the soil showed no contamination but for Mercury and Cadmium showed severe contamination.
Health and environment
MohammadHossein Saghi; reza malayjerdya; SEDIGHE RASTAGHI; A Rastgar; hosein rezaee
Volume 27, Issue 4 , November and December 2020, , Pages 514-519
Abstract
Introduction: In recent years, the uses of chemical pesticides in agricultural crops more than the world standards. The aim of this study was evaluate the knowledge, attitude and practice of farmers in Jovuin on the environmental health aspects of pesticide use in the 2018 years.
Materials and Methods: ...
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Introduction: In recent years, the uses of chemical pesticides in agricultural crops more than the world standards. The aim of this study was evaluate the knowledge, attitude and practice of farmers in Jovuin on the environmental health aspects of pesticide use in the 2018 years.
Materials and Methods: This is a cross-sectional study. The population of this study is farmers of Jouvin of Khorasan Razavi province. The sample size for study was 100 farmers. The data obtained with a standard questionnaire and data analysis was performed using SPSS version 20 software.
Results: The knowledge, attitude and practice of farmers in relation to environmental health and safety principles during spraying indicate that the average score was 12.43 in attitude and awareness, but the very low mean score of individuals (5.46) in the performance. Also Pearson analysis showed the have scientific relation with attitude and awareness. (P-Value>0.05)
Conclusion: The practice of farmers in this study has received a very low score. This subject requires the scientific and practical training of farmers so that they can be used to reduce the amount of toxins consumed and thus reduce the pollution of the environment
Health and environment
ahmad jonodi; Ayoob Rastegar
Volume 25, Issue 5 , November and December 2018, , Pages 639-648
Abstract
Back ground: Phenol and its derivatives are widely used as raw material in many petrochemical, chemical and pharmaceutical industries. Wastewaters from the industries mentioned above contain Phenolic compounds which are highly hazardous to aquatic life. Therefore, phenolic wastewaters must be specially ...
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Back ground: Phenol and its derivatives are widely used as raw material in many petrochemical, chemical and pharmaceutical industries. Wastewaters from the industries mentioned above contain Phenolic compounds which are highly hazardous to aquatic life. Therefore, phenolic wastewaters must be specially treated before disposing off the effluentsMaterials and methods: Hybrid aerogel with structure of hydrophobicity was prepared through sol–gel synthesis followed by drying at ambient. The aerogel was used for phenol adsorption from water and the effects of phenol concentration, also contact time were studied. Batch kinetic and isotherm studies were carried out to evaluate the effects of contact time and phenol concentration The Aerogel surface was characterized by nitrogen adsorption at 77 K.Results: The result showed that the maximum adsorption was in the concentration 250 mg L− 1 493/13 mg g− 1. The specific surface area of the synthesized aerogel is 543.4 g m-2, the pore size is 3.24 nm with a porosity of 44 and a contact angle of 156 degrees, The Langmuir model and the pseudo-second-order fited the experimental data Conclusion: the results showed that the phenol adsorption process involved both boundary layer diffusion and inter particle diffusion that hydrophilic and hydrophobic surface of the aerogel is synthesizedmain reason for its higher adsorption efficiency phenol.
Health and environment
Akram Eskandariyan; Sahar Sadat Azad; Abolfazl Rahmani Sani; Ayoob Rastegar; Ahmad Alahabadi
Volume 24, Issue 3 , July and August 2017, , Pages 183-189
Abstract
Background& Objectives: Antibiotics are a group of synthetic organic materials that are not removable by biological treatment process and need to be treated by advanced process like surface absorption. Since activated carbon is one of the best choices for using as adsorbent, this project was aimed ...
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Background& Objectives: Antibiotics are a group of synthetic organic materials that are not removable by biological treatment process and need to be treated by advanced process like surface absorption. Since activated carbon is one of the best choices for using as adsorbent, this project was aimed on the removal of amoxicillin antibiotic from aquatics solutions by a novel modified activated carbon.
Materials & Method: The present study was an experimental study which was conducted by using batch wise method. Erlenmeyers with 100 mL volume containing 50 mL of amoxicillin with a known concentration and amount of adsorbent were shacked at different pHs, contact times and temperatures. The samples were filtered by vacuumed pump using 0.04 acetate cellulous filter and the residual of amoxicillin was determined by UV spectrophotometer at 228 nm using quarts cell.
Results: The results obtained from experimental data was shown that the best efficiency of amoxicillin removal from aquatic solution by the new activated carbon takes places at pH= 6, adsorbent dose of 0.06 g/L and 20 min contact time. In this project the used activated carbon efficiency was 75.5%, in antibiotic concentration of 50 mg/L. Isotherm studies were shown that the amoxicillin absorption can be explained by both Langmuir and Freundlich models, and the degree of reaction obtained from kinetic studies was of second order.
.Conclusion: With regard to acceptable worth capacity of the new activated carbon, it was suitable to replace standard Merck carbon for water and wastewater treatment.
Mahdi Farzadkia; Leila Ghasemi; Ahmad Alah Abadi; Ayoob Rastegar
Abstract
Objectives Recycling is one of the methods to improve the management of solid waste, which has considerable economic and environmental benefits. Without knowing the amount of the waste and its components, the possibility of planning and optimizing the waste management system is impossible. The current ...
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Objectives Recycling is one of the methods to improve the management of solid waste, which has considerable economic and environmental benefits. Without knowing the amount of the waste and its components, the possibility of planning and optimizing the waste management system is impossible. The current study aimed at investigating the recycling potential of solid wastes in 13 municipal districts of Mashhad, Iran, quantitatively and qualitatively.Methods The current study was conducted in 2013 in 13 municipal districts of Mashhad. To conduct the study, it was necessary to know the physical analysis of municipal waste solid; therefore, the latest data of Waste Management Organization of Mashhad were used. Results The solid ingredients of the studied waste were paper and cardboard (46.7%), bread (10.8%), plastics (9.7%), metals (6.8%), and glasses (5%), respectively. There was a significant difference between the mean of the studied solid waste in winter and summer months. The total proceeds from the recycled materials was about US$ 369 836.45. The proceeds from the recycled metals was even more than that of other dry waste.Conclusion The recycled dry solid waste compromised 26.15% of the total dry solid waste. It is suggested to establish a waste separation system and also systematize the existing recycling industries in Mashhad according to the regulations to reduce the amount of solid waste, mange the costs and benefits result from Mashhad solid waste, and create new job opportunities and sources of income.
Zahra Rezaei Gozal Abad; Ahmad Alah Abadi; Ahmad Hosseini-Bandegharaei; Ayoob Rastegar; Farzad Mohammadi; Shahram Nazari
Volume 23, Issue 4 , September and October 2016, , Pages 608-617
Abstract
Objectives Phenol is known as a toxic and carcinogen compound in the environment. It also produces unpleasant taste and odor in water reservoirs. In this study, the efficiencies of modified and conventional rice husk ashes as low-cost adsorbents were compared regarding phenol removal from aqueous solutions. ...
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Objectives Phenol is known as a toxic and carcinogen compound in the environment. It also produces unpleasant taste and odor in water reservoirs. In this study, the efficiencies of modified and conventional rice husk ashes as low-cost adsorbents were compared regarding phenol removal from aqueous solutions. Methods This study is an interventional laboratory research in which, at first carbonized rice husk was prepared at a temperature of 450°C. Then, to improve rice husk ash adsorption capacity, NH4CL was used for its modification. Then, the effects of physiochemical factors (pH, contact time, phenol concentration and adsorbent dose) on phenol removal were studied. Results Findings showed that the phenol removal by modified and conventional rice husk ash was 94.85% and 52.8%, respectively. The adsorption process for both adsorbents followed Freundlich isotherm (R2≥ 0. 99) and the pseudo-second order model (R2>0.99). Maximum adsorption capacity based on Langmuir model for the modified and conventional husk rice ashes were 66.6 mg/g and 4.7 mg/g, respectively. Conclusion Results indicated that efficiency of modified husk rice ash was more than that of the conventional type in phenol removal, causing less adsorbent consuming in the industrial treatment plants. Therefore, because of its availability and easy modification, it can be used in water and wastewater technology for phenol removal.
Ayyob Rastegar; Leila Ghasemi; Ahmad Allahabadi; Mehdi Farzadkia
Volume 22, Issue 6 , January and February 2016, , Pages 937-943
Abstract
Introduction: One of the ways of optimizing the management of solid waste, is recycling which has considerable economic and environmental benefits. Whitout knowing the amount of the waste and its components, the possibility of accurate planning and optimization of the waste management system does not ...
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Introduction: One of the ways of optimizing the management of solid waste, is recycling which has considerable economic and environmental benefits. Whitout knowing the amount of the waste and its components, the possibility of accurate planning and optimization of the waste management system does not exist. The aim of this study was to evaluate a quantitative and qualitative and recycling potential of solid wastes in 13 regions of Mashhad. Methods: This study was conducted during the 12 mounths of 2012 in 13 regions of Mashhad municipality. This research was needed to know the phisical analysis of waste, so the information and statistical analysis of Waste Management Organization of Mashhad was used. Results: The solid parts of studied waste were paper and cardboard (46.7%), bread (10.8%), plastic (9.7%), metals (6.8%), glass (5%) and others (20%). There was a significant relationship between the amount of solid wastes in winter and summer months. The total income from selling of recycled materials was 14,793,458,000 rials. The income from selling of recycled paper is higher than other dry wastes. Conclusions: The amount of recycled dry solid waste was26.15%. It is recommended that by performing comprehensive studies and appropriate managemnt can effectively increase the percentage ofrecycling dry waste as well as proper recycling will lead to revenue and creating jobs in this sector.
Ali Azari; Saeed Nazemi; Babak Kakavandi; Ayyob Rastegar
Volume 22, Issue 6 , January and February 2016, , Pages 944-954
Abstract
Background: Corrosion and scaling are the main problems that water facilities still face with them. Corrosion can caused great financial losses and health damage to the system, and consumers. Blockages and pressure drop in the network are another disadvantage of scaling. The aim of present study was ...
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Background: Corrosion and scaling are the main problems that water facilities still face with them. Corrosion can caused great financial losses and health damage to the system, and consumers. Blockages and pressure drop in the network are another disadvantage of scaling. The aim of present study was to determine the corrosive and scaling potential in drinking water resources of Shahrood city.
Materials and Methods: This crosses-sectional study was conducted over 4 seasons in 2013 years. 1104 samples were examined using Langelier (LSI), Rayznr (RSI), aggressive (AI) and Pokurious (PSI) indices to determine the corrosive and scaling potential in drinking water resources of Shahrood city. To compare the mean values of each indices, the results were analyzed using t-test.
Results: The results indicate that the drinking water resources of Shahrood according to the Langelier index equals -1.03 with a standard deviation of 0.11, according to Rayznr index equals 9.72 with a standard deviation of 0.17, based on Aggressive index equals 12.10 with a standard deviation of 0.14, based on Pokurious index equals 9.59 with a standard deviation of 0.13 respectively. The difference between the mean values of the four studied seasons also were significant. P-value< (0.05)
Conclusion: Comparison of four indices and obtained results showed that drinking water resources in Shahrood was corrosive, therefore, it is suggested that the city's water resources should constantly assessed and try adjusting the pH and control of other affecting factors on the corrosion such as chloride, dissolved oxygen and sulfate concentrations to reduce corrosion.
Ahmadreza Yari; Shahram Nazari; Gharib Majidi; Sodabeh Alizadeh Motobave; Esrafil Asgari; Ayyob Rastegar; Samaneh Dehghan
Volume 22, Issue 6 , January and February 2016, , Pages 982-991
Abstract
Background: Organic dyes, with a complex structure, often toxic, carcinogenic, mutagenic, non-biodegradation and stable in the environment are and if without treatment enter the environment can endanger the environment and human health. The aim of this study was to nanoparticles zero valent iron synthesis ...
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Background: Organic dyes, with a complex structure, often toxic, carcinogenic, mutagenic, non-biodegradation and stable in the environment are and if without treatment enter the environment can endanger the environment and human health. The aim of this study was to nanoparticles zero valent iron synthesis andevaluate the performance of H2O2 and H2O2/Fe0 for the removal of dye Acid Red 18 from aqueous environments.
Materials and Methods: This study was conducted at the laboratory scale. Nanoparticles were synthesized by reduction of ferric chloride using sodium borohydride and then removal efficiency of Acid Red 18 from a synthetic solution by H2O2 and H2O2/Fe0 was investigated. As well as effect of solution pH, dye concentration, concentration of nano zero valent iron, H2O2 and time contact in decolorization efficiency was investigated.
Results: Results show that in the pH=3, contact time of 80 minutes, dye concentration of 75 mg/L and Concentration of nano zero valent iron, 2 g/L and H2O2, 200Mmol, about 90% day removal was observed.
Conclusions: According to the results of experiments, the use to be of H2O2/Fe0 the efficiency in dye removal of Acid Red 18.
Ayyob Rastegar; Zahra Rezaee Gezal Abad; Ahmad Allahabadi; Abolfazl Rahmani Sani; RamezanAli Khamirchi
Volume 21, Issue 6 , January and February 2015, , Pages 1090-1102
Abstract
Background: Aniline is an important chemical compound which has wide applications in several industries such as dyestuffs, rubbers, pesticides and plastics. It is highly toxic and has injurious influences on human physical conditions and aquatic life. Therefore the purpose of this study is to investigate ...
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Background: Aniline is an important chemical compound which has wide applications in several industries such as dyestuffs, rubbers, pesticides and plastics. It is highly toxic and has injurious influences on human physical conditions and aquatic life. Therefore the purpose of this study is to investigate the effects of NH4Cl-induced activated carbon (NAC) and standard activated carbon (SAC) in aniline removal from aqueous solutions were investigated. Material & method: This study is of experimental–intervention type. An UV-Visible spectrophotometer (CECIL CE7400) used For determination of remaining aniline concentrations. The effect of various parameters like adsorbent dose, pH, contact time and initial aniline concentration were studied for optimization.
Results: The results showed that the prepared NAC had a higher absorption capacity than standard activated one. The maximum adsorption capacity of aniline onto SAC and NAC was 1666 and 1000 mg/g, respectively, and the rate removal was dependended to pH, contact time, aniline concentration and absorption type. Results of equilibrium experiments indicated that the adsorption process of aniline onto SAC and NAC follows Langmuir model (R 2> 0.99.47 and 0.99,776 ). Also, kinetics of adsorption process follows pseudo second-order model with correlation R2> 0.99.97 and 0.99,30 respectively for SAC and NAC.
Conclusion: These consequences show that the developed NAC was a more competent adsorbent than SAS for removal aniline in water.
Mehran Eyvazzadeh; MohammadHasan Rakhshani; Ayyob Rastegar; Ahmad Allahabadi; Ebrahim Manochehriyan; Fatemeh Dareyni; Abolfazl Rahmanisani
Volume 21, Issue 5 , September and October 2014, , Pages 934-941
Abstract
Background: In recent years, crisis of water shortage has become a serious problem in many countries. In this regard, the use of treated wastewater in natural or artificial method in agriculture and the like, has been proposed as an important and practical solution. The natural purification method by ...
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Background: In recent years, crisis of water shortage has become a serious problem in many countries. In this regard, the use of treated wastewater in natural or artificial method in agriculture and the like, has been proposed as an important and practical solution. The natural purification method by the use of artificial canebrakes, compared with other methods of treatment is an appropriate method because of its low cost, and also, because of easy navigation, the requirements of low technology and low energy consumption. Several herbs have been used to increase the efficiency canebrakes which including special plants to purify such wastewater is Vetiveria that has unique genetic, morphological and physiological characteristics. Due to the limited knowledge of the plant's industrial wastewater treatment, in this study, a comparison of filterablity of hospital wastewater was done between Vetivaria and bulrush in tropical areas.
Methods: This experimental study was done in 2013 in the hot season, summer. In this study, was made two pilot glass with dimensions of 50*60*100 Cm. A mixture of soil, sand, gravel, clay soil was selected. The irrigation method in this study was subsurface and continuous. First, hospital wastewater via a 220 liter tank as the primary sedimentation retention time and with time of 2 hours entered into bed with a hydraulic retention time of 4 days to discharge 85/0 liters per hour. To evaluate the efficiency of each plant in the treatment of hospital wastewater, chemical parameters including (PH, TP, TN , TSS, BOD5, COD)were measured according to standard methods of measuring. . Analysis of the data was done by the use of t-test and Mann-Whitney and SPSS software.
Results :Based on the finding of this study, percentage of removal parameter(Bod5,Tss,Tn,Tp) by plant Vetiveria was (88.54,95.71,93.93,99.80) and for bulrush was (82.54,91.13,86.64,99.28).
Conclusion: Due to the unique characteristics of Vetiveria, such as high resistance against unfavorable environmental conditions and its higher efficiency than bulrush, this plant is recommended for the treatment of hospital wastewater.
Ayoub Rastegar; AmirHossein Mahvi; Aliakbar Mohammadi; Hossein Faraji
Volume 21, Issue 2 , May and June 2014, , Pages 293-301
Abstract
Background: Underground water resources constitute an important part of urban water resources. One of the serious challenges in ensuring and promoting community health is gradual increase in nitrate levels of drinking water of communities across the world. The purpose of this study was to investigate ...
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Background: Underground water resources constitute an important part of urban water resources. One of the serious challenges in ensuring and promoting community health is gradual increase in nitrate levels of drinking water of communities across the world. The purpose of this study was to investigate the seasonal variation of nitrate and ammonia levels in drinking water wells of Babol city using GIS software, in 2010-11.
Materials and Methods: This cross-sectional analytical study was performed on drinking water wells of Babol city in 2010-11. Sampling was done according to a standard method from 20 drinking water wells, in different seasons; and in final, 80 water samples were analyzed. Nitrate and ammonia concentration of samples was measured using Spectrophotometer DR2000 (Hach company) in 500 and 425 nm, respectively. For qualitative analysis and seasonal fluctuation of nitrate and ammonia concentration of different areas, Geographic information systems , ArcGIS, was used.
Results: The results showed that the highest amount of nitrate was in summer (23.68 mg/l), and the lowest was in winter (14 mg/l). While the highest and the lowest amount of ammonia was in spring (0.43 mg/l) and summer (0.06 mg/l), respectively. Also, the results showed that only in well number 5 located in Kate Sofla village, nitrate concentration had increasing trend, and in the remaining wells, nitrate and ammonia concentration, had an increasing and a decreasing trend, respectively.
Conclusion: The results indicate that nitrate and ammonia levels in all samples were lower than the WHO recommendations. To avoid increasing in the ammonia and nitrate concentrations in the underground waters, ongoing training to farmers on the proper use of chemical fertilizers, as well as the construction and operation of wastewater collection systems are recommended.
Ehsan Ahmadi; Ayyob Rastegar; Mehdi Farzadkia; Ali Azari
Volume 20, Issue 4 , January and February 2014, , Pages 530-538
Abstract
Background &Objective: According to the existing documents a major portion of municipal solid wastes in Iran is being land filled and small portion of this material is recycled, while the municipal waste management in developing countries has moved towards source separation and recycling .This research ...
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Background &Objective: According to the existing documents a major portion of municipal solid wastes in Iran is being land filled and small portion of this material is recycled, while the municipal waste management in developing countries has moved towards source separation and recycling .This research was conducted by the purpose of estimating Qom municipal solid waste recycling potential and cost benefit,s in a 20-year vision since 2006.
Materials & Methods: This Research is a cross-sectional study. Firstly, according to the reports given by waste management organization in Qom city, dry solid waste recycling in 2006 and 2011 was estimated. Then two scenarios consisted of 20 and 60 percents of recycling were estimated to process the solid waste in 2011 and 2028 for enhancing recycling level ,and then cost benefit of them was determined.
Results: The average of produced solid waste was 718 ton per day in Qom city in 2011. Due to this producing process in 1407 we will have 1145 ton solid waste per day in this city. Daily economic benefit of dry solid waste recycling in 2011 was 15801520 Rials. If the recycling programs promotes, this benefit can be increased to 63211640 and 189664400 Rials for 20 to 60%recycling level.
Conclusion: Despite of 21 % potential for dry solid waste recycling in Qom city, nowadays about 5% of this substances are recycling. By upgrading the plan for 10 to 20 years, amount of economic benefit can be increased to 4 to 12 times.
Akbar Ahmadi Asour; Mohammad Hossein Saghi; Ramezanali Khamirchi; Tahereh Vaziri; Ayyob Rastegar
Volume 20, Issue 2 , May and June 2013, , Pages 222-229
Abstract
Introduction: Unnecessary use of chemical manure in order to increase the crop production, particularly in the agricultural sector, causes environmental damages and disorder in terms of soil fertility. In the manure preparation method through the biogas, organic manure of high quality can be produced ...
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Introduction: Unnecessary use of chemical manure in order to increase the crop production, particularly in the agricultural sector, causes environmental damages and disorder in terms of soil fertility. In the manure preparation method through the biogas, organic manure of high quality can be produced in addition to obtaining gas. The purpose of this study is to examine the physical as well as chemical properties of the manure produced by the combined wastes of livestock and poultry using biogas system.
Research method: In order to put the pilot project into operation, livestock and poultry wastes were primarily collected and were added to the planned pilot in a proportional ratio of 1:2. After about two months, the produced gas was measured and the parameters of the manure were analyzed according to the pilot sample and subsequently, they were compared with the existing standards. Using EXCEL, the gathered data were analyzed.
Results: PH rate obtained from the manure was estimated to be 7.2. Reportedly, the electrical conductivity of the sample was equal to 29.53 ml. Siemens/cm. and the humidity was 5%. The organic compounds in the sample were 8.19% and ash was 8.58%. Furthermore, the rate of the organic carbon for the sample was 40% and the size of the uniformed particles was of the highest mesh, i.e. 50. The manure obtained has a phosphorous concentration of 1 mg/l and the sodium concentration obtained were 94 mg/l and potassium 74 mg/l.
Discussion and conclusion: Findings indicate that the rate of organic materials, phosphorus, ash and organic carbon are consistent with the standards set by WHO. With regard to low cost, availability, being danger-free and enriched as well as the simultaneous use of the gas produced, the manure obtained through the biogas can be considered a suitable kind of manure for agriculture.
Yosef Pour Eshgh; Ayyob Rastegar; Ahmad Allahabadi; Zahra Rezaee Gazal abad; Abdolmajid Gholizadeh
Volume 20, Issue 1 , March and April 2013, , Pages 72-83
Abstract
Background: The effluent of textile industries is high dyefully and this is one of most problems for environmental health engineers. Two Azo dyes biosorption, direct black 19 and direct red 23, on Cystoseira indica, an invasive macroalga in Iran, has been investigated using visible absorption spectroscopy. ...
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Background: The effluent of textile industries is high dyefully and this is one of most problems for environmental health engineers. Two Azo dyes biosorption, direct black 19 and direct red 23, on Cystoseira indica, an invasive macroalga in Iran, has been investigated using visible absorption spectroscopy.
Materials and methods: Pre-treatment and chemical cross-linking with CaCl2, have been conducted in order to improve the stability as well as the biosorption capacity of the algal biomass. All measurements were conducted by UV-Visible Spectrophotometer. The effects of operating parameters such as contact time, pH, initial dye concentration and amount of biosorbent on the dye removal efficiency were investigated. The biosorption has been described in terms of isotherm and kinetic models; from the maximum adsorption capacity values, an estimation of the algal specific surface area was made.
Results: It has been found that biosorption kinetics can be described according to the pseudo second order model and biosorption equilibrated for 120 min (89.3% of direct red 23 and 69.02% of direct black 19 removed). Maximum biosorption found at pH 5 (2.4mg/g). It also observed increasing initial dye concentration and decreasing biomass dosage would reduce dye removal. Isotherm studies also revealed the dye biosorption on algal biomass followed from Freundlich model. Conclusion: Biosorption of selected Azo dyes onto algal biomass, Cystoseira indica was fast and more dye is eliminated in the first hour. So, by determining the optimum conditions of contact time, pH, initial dye concentration and biosorbent dosage, Cystoseira indica can be used as an inexpensive sorbent for removal of Azo dyes from aqueous solutions.
Roshanak Rezaei Kalantary; Ahmad Allah-Abadi; Mehdi Farzadkia; Ayyob Rastgar; Ahmad Joneidi Jafari; Abdolmajid Gholizadeh
Volume 19, Issue 3 , September and October 2012, , Pages 277-286
Abstract
Background: Leaching of nutrients and heavy metals from municipal solid waste compost leads to accumulation of certain elements in soil layers, causing underground water pollution. The objective of this study was to investigate the effect of compost on leaching and adsorption of heavy metals and nutrients ...
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Background: Leaching of nutrients and heavy metals from municipal solid waste compost leads to accumulation of certain elements in soil layers, causing underground water pollution. The objective of this study was to investigate the effect of compost on leaching and adsorption of heavy metals and nutrients (sodium, potassium, and sulfate) from silt-loamy soils. Materials and Methods: In this empirical, applied study, three polyethylene columns (height 50 cm, inner diameter 10 cm), filled with sandy clay loam soil, were randomly selected. Then, 10 kg of compost per square meter were sprayed onto the columns, and leachates exiting the columns were routinely analyzed for pH, electrical conductivity, sulfate, sodium, potassium, lead, chromium, and cadmium. Data analysis was performed with Excel and SPSS software using Kruskall-Wallis test. Results: The data showed that the use of enriched and unenriched compost leachate decreased pH (from 7.43±17.0 to 6.7±0.25 and 7.07±0.11, respectively) and increased the electrical conductivity (EC) (from 1.8±0.3 mSiemens/m to 3.7±0.12 and 12.87±0.41 mSiemens/m respectively). Leakage of metals in the unenriched treatments was not significantly different from the control (p>0.78), but leakage with three metal-enriched compost applications was significant compared with control (p