hossein movahedian attar

Microplastics (MPs) exposure can affect humans in various ways, with tap water being one of the potential sources. Microplastics can absorb other pollutants and pose risks to both humans and the environment.

The aim of this study was to investigate the presence of MPs in tap water from the drinking water distribution system of Isfahan, Iran, and to determine the exposure to MPs from drinking tap water.

Samples were collected from different points in the drinking water distribution system of Isfahan, Iran. Samples were prepared for analysis through filtration and chemical digestion. The MPs were counted using a scanning electron microscope (SEM), and the composition of MPs was analyzed using a micro-Raman spectrometer.

The concentration of MPs in tap water was found to be 287.0 ± 65.9 MPs/l. MPs ≤ 10 µm were the predominant sizes, and fibers were the predominant shape. Polyethylene terephthalate, polyethylene, and polypropylene were the most frequently identified MPs, respectively.

Considering that the Iranian population consumes 7 - 15 liters of water daily for drinking and cooking, it is estimated that the average intake of MPs through cooking and drinking water is 2009 - 43,051 particles per day.

The escalating production and utilization of plastics, driven by their distinctive properties, have significantly contributed to environmental pollution. One of these pollutants is microplastic (MP), which is present in many food products, such as tea bags. The primary objective of this study was to investigate the presence and characteristics of MPs in tea bags from five different brands in Iran.

For this study, 30 tea bags from five different brands in Iran were selected for sampling. The unaltered tea bags (with tea) were placed in 100 mL of ultrapure water at a temperature of 95 °C for 5 minutes, representing an alternative approach involving tea bag sampling with tea and without rinsing. Subsequently, the samples were subjected to quantitative analysis using a scanning electron microscope (SEM) and qualitative analysis using a micro-Raman spectrometer.

All brands exhibited MP contamination, with an average abundance of 518 459 items per individual tea bag. Fibers were the predominant form of MPs, primarily falling within the 10–50 μm size range. Polymer analysis identified cellulose acetate (CA), nylon, polyethylene terephthalate (PET), and polyethylene (PE) as the prevalent types, with CA and nylon as the most frequent ones. The estimated daily intake (EDI) of MPs was calculated at approximately 17,282 items/kg-BW/day for children consuming 100 ml of tea daily and 14,813 items/kg-BW/day for adults consuming 400 mL of tea daily.

This study underscores tea bag consumption as a significant route of MP exposure for humans and the environment, posing potential risks and implications.

In recent decades, there has been a growing concern about the presence of antibiotics in water resources. The presence of these micropollutants even in low concentrations has significant effects on the environment and human health, and their entry into the soil and especially receiving waters should be prevented as much as possible. As effluents from wastewater treatment plants (WWTPs) are significant sources of antibiotics in the environment, this study aimed to investigate the efficiency of antibiotics removal in municipal WWTPs.

In this study, Isfahan East WWTP with a combination of stabilization ponds and an aeration lagoon, and Isfahan South WWTP with conventional activated sludge treatment were selected as well as four antibiotics from the beta-lactam group including ampicillin, amoxicillin, cephalexin, and penicillin, and their removal efficiency was investigated in both WWTPs. Samples were collected from the influent and effluent of both WWTPs on 13 occasions and analyzed immediately after being transferred to the laboratory. The concentration of antibiotics was determined by high-performance liquid chromatography (HPLC).

In the Isfahan East WWTP, the average removal efficiency was 86.22 ± 19.84% for ampicillin, 34.35 ± 31.38% for amoxicillin, 78.75 ± 23.81% for cephalexin, and 89.80 ± 19.42% for penicillin. In the Isfahan South WWTP, the average removal efficiencies of amoxicillin, ampicillin, cephalexin, and penicillin were equal to 54.82 ± 33.29%, 66.85 ± 24.88%, 87.65 ± 21.76%, and 82.76 ± 21.85%, respectively.

The study's findings revealed that Isfahan municipal WWTPs were unable to fully eliminate antibiotics. According to statistical analysis, there were significant differences in the concentration of antibiotics in both WWTPs, and no critical correlation was observed between the removal efficiency of antibiotics and other principal wastewater parameters. Consequently, there is a need for stricter control over the discharge of effluent into the river or its use for agricultural irrigation.

Based on the previous studies, antibiotics can have affected biological properties of biomass and fouling properties of mixed liquor in aeration tank. The present study was conducted to explore the fouling mechanisms of membrane bioreactor (MBR) system during the treatment of wastewater containing erythromycin (ERY) antibiotic under several mixed liquor suspended solids (MLSS) concentrations.

A lab-scale two-chamber MBR system equipped with a polypropylene hollow fiber submerged membrane was fed with synthetic wastewater containing different initial concentrations of ERY. MBR system was operated under the constant flux mode and different MLSS concentrations (5.0-13.0 g/L) and the obtained results were evaluated using different individual and combined fouling models.

The variation of MLSS concentrations had not significantly affected the kind of best-fitted model. From the individual models, the standard model indicated the best performance for permeate prediction under different MLSS concentrations (R2 adj > 0.997). For all studied MLSS concentrations, the R2 adj values of combined fouling models were higher than 0.986 and demonstrated good fitness performance of combined models compared to individual models. Overall, the cake-intermediate model showed the lowest fitness, and cake-complete and complete-standard models were the most successful models in filtrated volume prediction in comparison with other combined fouling models.

This study indicated that mechanistic models are suitable for fouling prediction of MBR systems in ERY removal and under a wide range of MLSS concentrations and provide valuable information on fouling mechanisms of full-scale MBR systems.

Microplastics (MPs) are nowadays found in the air and in various terrestrial and aquatic environments and have become emerging pollutants. These particles can absorb other chemicals and microbial contaminants and release them into the environment and food chain. Despite the high efficiency of wastewater treatment plants (WWTPs) in removing MPs, WWTPs are still one of the major sources of MPs discharge to the environment. This study was conducted to evaluate the efficiency of MPs removal in a municipal WWTP with conventional activated sludge in Iran.

MPs particles were counted using a stereomicroscope after the initial preparation steps (sieving, chemical digestion with the catalytic wet peroxidation-oxidation and density separation with NaCl) and then analyzed for particle composition using a Raman micro-spectrometer.

MPs concentration in the influent, grit chamber, primary sedimentation tank, and effluent were 843.2 ± 147.5, 315.5 ± 54.7, 80.2 ± 19.1, and 11.13 ± 3.14 items/L, respectively. The overall MPs removal efficiency of the WWTP was 98.7%, with the grit chamber, primary sedimentation tank, and secondary sedimentation tank removed 62.6%, 27.9%, and 8.2% of the total MPs, respectively. The most abundant polymers were polypropylene (PP) and polyethylene (PE).

Despite the effective removal of MPs in WWTP, on average 4.47 × 1011 ± 1.03 × 1011 MPs are discharged into the receiving waters through the effluent of this WWTP annually. This means that WWTPs can be one of the major sources of MPs in the environment and efforts should be made to increase the efficiency of WWTPs and equip them with advanced technologies.

Treatment of combined industrial wastewater from industrial parks is one of the most complex and difficult wastewater treatment processes. Also, the accuracy of biological models for the prediction of the performance of these processes has not been sufficiently evaluated. Therefore, in this study, the International Association on Water Quality (IAWQ(-Activated Sludge Model No. 1 (ASM1) was implemented for the Jey industrial park in Isfahan province, Iran.

The Jey IPWWTP process is a combination of anaerobic and aerobic biological processes. To evaluate the overall performance of IPWWTP, organic compounds, suspended solids, nutrients, attached biomass, and some operating parameters were measured during 6 months. Then, the biokinetic coefficients of aerobic processes were determined using Monod equations. Finally, the aerobic processes were modeled using ASM1 implemented in STOAT software.

The values of the biokinetic coefficients K, Y, Ks, Kd, and µmax were calculated as 2.7d-, 0.34 mg VSS/mg COD, 133.36 mg/L COD, 0.03d-, and 0.93d-, respectively. Based on the default coefficients and conditions of the ASM model, the difference between the experiments and model prediction was about 2 to 98%. After calibrating the ASM model, the difference between the experiments and prediction in all parameters was reduced to less than 10%.

Investigations showed that the default coefficients and operation conditions of the ASM1 model do not have good predictability for complex industrial wastewaters and the outputs show a low accuracy compared to the experiments. After calibrating the kinetic coefficients and operating conditions, the model performance is acceptable and the predictions show a good agreement with the experiments.

In recent years, the world has faced with the COVID-19 pandemic, followed by a significant increase in the use of antibiotics to control the COVID-19 and other secondary infections. The non-biodegradable characteristics of antibiotics and their residues in the environment leads to increased microbial and drug resistance. Therefore, due to the high importance of antibiotics, two antibiotics, ampicillin and penicillin G, were studied in Isfahan municipal WWTPs.

Sampling was performed for two months during 13 sampling periods and antibiotics were measured using high-performance liquid chromatography with UV detector (HPLC/UV) instrument.

Ampicillin and penicillin G were identified in all samples taken from the both WWTPs. The average concentration of penicillin G in WWTP E and S at the influent, effluent and its removal efficiency were 1050.54±761.43 μg/L, 52.89±49.27 μg/L, 89.80±19.42%, 2055.12±1788.08 μg/L, 143.01±162.59 μg/L and 82.76±21.85%, respectively. Also, the average concentration of ampicillin in WWTP E and S in the influent (796.44 ± 809.6 and 447.1±322.39 μg/L), effluent (48.94 ± 24.25 and 90.31±75.91 μg/L), and its removal efficiency (86.22 ± 19.84% and 66.85±24.88%) were determined.

In two studied WWTPs, the concentration of antibiotics was higher during the COVID-19 pandemic in comparison with previous studies. The statistical analysis showed that there was no significant relationship between the concentration of antibiotics in WWTPs (P<0.05). Also, the statistical results indicated that the correlation is not significant between removal efficiency of antibiotics and removal efficiency of wastewater main parameters.

Industrial wastewater treatment has always been difficult and costly due to the presence of different and high concentrated pollutants. The use of constructed wetlands is economical due to the need to use no external energy sources and materials and equipment to reduce pollutants. The aim of this study was to determine the efficiency of horizontal and vertical subsurface wetlands in the removal of pollutants from the wastewater of the Mourchekhort Industrial Estate and its comparison with performance of the conventional coagulation-flocculation-filtration unit of reuse process.

Two horizontal and vertical wetlands in pilot scale and two control (no plant) reactors were operated for eight months. Removal efficiency of TSS, COD, turbidity, phosphorous and nitrogen compounds and index bacteria were evaluated. Horizontal wetlands with dimensions of 0.8 × 0.65 × 2 m and floor slope of 1% were considered. HRT equal to 6 days and incoming sewage flow rate set to 0.2 m3/d. Vertical subsurface reed had dimensions of 0.4 × 0.60 × 2 m and floor slope was equal to 1%. The control pilot (no plant) was designed exactly the same as the horizontal and vertical tests. The results were compared with coagulation-flocculation-filtration process.

The efficiency of vertical wetland in removal of TSS, COD, turbidity, phosphorus and nitrogen compounds and index bacteria were: 58.1, 62.4, 73.4, 20.41, 21.34, 40.51%; for horizontal wetland 57, 52.59, 70.3, 22.41, 18.22, 39.08%; and for conventional treatment process 85.34, 69.7, 81.55, 69.23, 73.95 and 78.2%, respectively.

Although vertical wetland was more efficient than horizontal one for most of the operation parameters, both of these wetlands were less efficient than conventional coagulation-flocculation-filtration unit of reuse process. Although operating costs of wetlands are low, these systems alone cannot be considered as a substitute for the conventional process because of their low performance for the purpose of polishing.

Recently, microplastics (MPs) have been found in the aquatic and terrestrial environments, air, and food. Other pollutants can be transported by MPs and pose a threat to the human, animal, and environment. Measurement and evaluation of microplastics can either increase knowledge about them or boost understanding of their possible harmful effects. However, no standard method has been established to measure microplastics and the measurement of microplastics has been done by various methods in different published studies. The aim of current study was to investigate different methods of measuring microplastics in water and wastewater environment and identifying the strengths and weaknesses of these methods.

The present review study was conducted during the winter 2021, by searching the papers cited in PubMed, Google Scholar, Web of Science, and Scopus databases using the keywords "Microplastic", "Water", "Drinking-water", "Wastewater", "Surface", "Bottled-water" and "Marine" and selecting articles published between 2015 and 2021 in reputable journals.

The main stages of MPs measuring in various studies included sampling and sieving, pretreatment and digestion, density separation, counting and Identification of MPs by their chemical composition.

Digestion using H2O2, density separation using NaCl, counting by stereomicroscope, and Spectroscopy using FTIR and micro-RAMAN are the most widely used methods in the studies related to detecting MPs in water and wastewater environment. However, different methods of measuring and identifying microplastics have made comparing the results of studies difficult and it seems that efforts should be made to standardize these methods.

 In this study, the microplastic (MP) concentration in several brands of salts was investigated. 

 Fifteen samples of crystallized salt, refined sea salt, unrefined sea salt, and rock salt were purchased from local markets and analyzed for MPs concentration. The salts were digested with the Catalytic Wet Peroxide Oxidation method first, and the MPs were floated based on density difference. Then, MPs were counted by scanning electron microscopy and nature was confirmed by using micro-Raman spectroscopy. 

 The MP concentrations in crystallized salt, refined sea salt, unrefined sea salt, and rock salt were 151.4 ± 48.8, 406.7 ± 93.3, 1417.4 ± 203.3, and 283.4 ± 97.0 MPs/kg, respectively. The most abundant polymers were polyethylene, polypropylene, and polyethylene terephthalate. The fiber was the dominant shape of MPs in all salt samples. 

 This study reveals the presence of MPs in crystallized salt, refined sea salt, unrefined sea salt, and rock salt. Therefore, the consumption of salts can expose humans to MPs.

The present study aimed to assess the acute impact of erythromycin (ERY) as an inhibitor on peptone mixture utilization of activated sludge (AS) consortium.
For this purpose, the inhibition of oxygen consumption was used based on the ISO 8192:2007 procedure. In this method, the AS consortium (10-day age) was extracted from labscale membrane bioreactor, then, percentage inhibition for total, heterotrophic, and nitrifying microorganisms, in separate batch respirometric tests were calculated in the absence and presence of N-allylthiourea (ATU) as a specifc Nitrifcation inhibitor.
The obtained data showed that the height of oxygen uptake rate (OUR) profles and amount of oxygen consumption reduced with increasing ERY dose. The half-maximal effective concentration (EC 50) of ERY for heterotrophic and nitrifer microorganisms were 269.4 and 1243.1 mg/L, respectively. In Run 1, the kinetic coeffcients bH, fA,H, YH, and µH were calculated as 2.61 d-1, 0.44, 0.4945 mg VSS/mg COD, and 0.047 d-1, respectively. Also, for maximum ERY concentration (1000 mg/L), the kinetic coeffcients bH., fA,H, YH, and µH were calculated as 2.27 d-1, 0.3, 0.4983 mg VSS/mg COD, and 0.0049 d-1, respectively.
The fndings showed that the inhibitory impact of ERY was observed as a decrease in the amount of oxygen consumption by OUR profles in rapid respirometric method (ISO 8192), which offered a novel insight for the acute inhibitory impact of this antibiotic. Also, chemical oxygen demand (COD) as an overall substrate parameter is most helpful in interpreting the behavior and the metabolic functions of AS systems.

Considering the development of industries and the importance of industrial waste production and its environmental hazards, it is important to survey the quantity and quality of waste. Therefore, the present study was conducted with the aim of properties investigation of waste produced from industrial units in Ure and Shoja Abad.

This descriptive cross-sectional study was performed in 2018. A questionnaire was used for quantitative and qualitative survey of industrial waste. For this purpose, after referring to the industrial units and completing the questionnaires, the data were analyzed to determine the status of industrial waste.

A total of 59730 and 168620 tons per year of industrial waste are respectively produced in Ure and Shoja Abad. Waste from non-metallic minerals has the highest amount of total production waste at 29460 and 151490 tons per year in Ureh and Shoja Abad, respectively.On-site recycling in the industries of Urea and Shoja Abad towns with 1212.74 and 434.91 tons per year, respectively, is the main method of waste management.

According to the results the main method of industrial waste management is on-site recycling. Non-metallic minerals are used and recycled in the production process to a greater extent than other production wastes in Urea and Shojaabad industrial plants.

Crude oil is a very complex composition containing thousands of hydrocarbons with different structure. Many compounds in crude oil, if entering in drinking, water can harmful on human health.
the effect of ozonation and powdered activated carbon separately and together for reducing the toxicity of crude oil in the water has been investigated. For toxicity test, different concentrations of water soluble fraction of crude oil in water and larvaeofrainbow trout were used. Before and after ozonatiopn and adding powder activated carbon, TOC and bioassay test was performed and the results were compared.
Findings: the ozonation at concentrations of 1 to 10 mg/l reduced the toxicity from 1.5 to 4 times. While, the use of activated carbon in concentration of 10 to 60 mg/l could decrease the toxicity in triplicate. The use of activated carbon and ozone in catalytic process can reduce the toxicity of the samples about 5 times.
the ozonation of the samples prior to activated carbon increases the adsorption and leads to better reduction of TOC and toxicity.

Leachatecontaining high levels of organic pollution with ammonia، halogenatedhydrocarbons، heavy metals and inorganic salts. Among the various methods fortreating leachate، has been developed membrane processes so that a morebiological process of membrane processes is used for separation of solid -liquid. The aimof this study was to evaluate the efficiency of Membrane bioreactor efficiencyin treatment of composting plant leachate.

This study is a cross-sectional study was carried outat a laboratory scale. In this study، SBR used with 5 litercombined with hollow fiber membrane reactor about 50% porosity and operational pressureMPa 0. 02. 150 samples were analyzed andaverage concentration of COD، ammonia، phosphorus and TSS was measured in inletleachate and bioreactor effluent. Finally removal efficiency was determined.

Bioreactor efficiency removal for COD، BOD5،TSS، ammonia and phosphorus، respectively were approximately 99. 2، 99، 89. 2،87and 98٪. The paired t test، showed astatistically significant difference between the input leachate and bioreactoreffluent (p-value <0. 05). based on one-sample t test، there aresignificantly different between values of the bioreactor effluent quality and standardsvalues (p-value <0. 05).

Raw leachate pretreatment processes such as microscreening، chemical precipitation، and ammonia stripping، anaerobic reactorswould be very effective in bioreactor performance.

Listeria and in particular Listeria monocytogenes is considered a ubiquitous foodborne pathogen which can lead listeriosis in human and animals. Listeriosis can be serious and may cause meningitis، septicemia and abortion in pregnant women. Although wastewater or sludge may contaminate foods of plant origin، there are no data on occurrence of Listeria spp. in wastewater and sludge in Iran. The purpose of current investigation was to study the occurrence of Listeria spp. in various samples of wastewater and sludge in Isfahan North wastewater treatment plant. Influent، effluent، raw sludge and dried sludge samples were collected from Isfahan North municipal wastewater treatment plant. L. monocytogenes were enumerated by a three–tube most probable number (MPN) assay using enrichment Fraser broth. A total of 65 various samples from five step in 13 visits were collected. The presence of Listeria spp. also was determined using USDA procedure. Then، phenotypically identified L. monocytogenes were further confirmed by Polymerase Chain Reaction amplification. L. monocytogenes isolated from 76. 9%، 38. 5%، 84. 6%، 69. 2% and 46. 2% of influent، effluent، raw sludge، stabilized sludge and dried sludge respectively. The efficiency of wastewater treatment processes، digester tank and drying bed in removal L. monocytogenes were 69. 6%، 64. 7% and 73. 4% respectively. All phenotypically identified L. monocytogenes were further confirmed by Polymerase Chain Reaction. The results of present study have shown that Listeriaspp. and L. monocytogenes in particular، were present in wastewater treatment plant effluents and sludge at high level. The bacteria may spread on agriculture land and contaminate foods of plant origin. This may cause a risk of spreading disease to human and animals.

 In this work, degradation of 4-chlorophenol (4-CP) was investigated in aqueous solutions using several oxidation systems involving ultraviolet/(UV)/H 2 O 2 , microwave (MW)/H 2 O 2 , and ultrasonic (US)/Fenton systems. 

 Three pilot plant reactors consist of a photolytic reactor, a modified domestic MW, and an US bath reactor of 22 kHz frequency were constructed and separately used in batch mode. The effects of several operation parameters such as pH of the solution ranging 3-10, H 2 O 2 initial concentration ranging from 0.005 to 0.2 mol/l, and reaction time were examined. Concentration changes of 4-CP were determined using a spectrophotometer at an absorption wavelength of 500 nm. 

 The results show that the oxidation rate was influenced by many factors, such as the pH value, reaction times, and the amount of H 2 O 2 concentration. The optimum conditions obtained for the best degradation rate were pH = 7, H 2 O 2 concentration of about 0.05 mol/l and pH = 10, H 2 O 2 concentration of about 0.1 mol/l for UV/H 2 O 2 and MW/H 2 O 2 system, respectively. For US/Fenton system, the highest 4-CP degradation was achieved in pH = 3, H 2 O 2 concentration of about 0.05 mol/l in the percent of 0.025 mmol Fe/l. The highest 4-CP removal rate in optimum conditions of pH and concentration of H 2 O 2 , in UV/H 2 O 2 , MW/H 2 O 2 , and US/Fenton systems was >99% over the retention time of 40 min, 85% after 180 min, and >99% after 40 min, respectively. 

 Based on the results of this study, the UV/H 2 O 2 and US/H 2 O 2 are successfully applicable for degradation of 4-CP in aqueous solution. Also, the kinetic study represented that the US/H 2 O 2 is capable of removing 4-CP slightly rather than UV/H 2 O 2 process.

 The objective of this study was to evaluate the prevalence of Listeria spp. in the river water before and after discharge of the effluent of the municipal wastewater treatment plant (WWTP) in Isfahan, Iran. 

 A total of 66 samples were collected bi-weekly over 4 months from eleven discrete sampling locations in Zayandehrood River, Iran. Three sampling sites were located above the discharge point and five sites were located after the discharge point of WWTP. Samples were also collected from the influent and the effluent of WWTP. Listeria spp. were isolated using a selective enrichment procedure and a subculture onto polymyxin-acriflavine-lithium chloride-ceftazidime-esculin-mannitol Agar. All isolates were subjected to standard biochemical tests. 

 L. monocytogenes was isolated from influent (83%), effluent (50%) and (18.5%) river water. Listeria spp. was not found before the discharge point in river water. However, L. monocytogenes was isolated in samples collected from 200 m (33%), 500 m (33%), 2 km (16.5%), 5 km (16.5%) and 10 km (16.5%) downstream from the WWTP. Listeria innocua (9%) and Listeria seeligeri (10%) were the second most frequently isolated species. 

 During the wastewater treatment, Listeria spp. is not removed completely. L. monocytogenes is widely distributed in the Zayandehrood river. L. monocytogenes released into surface water demonstrates a potential risk for public health. These results indicate the need for appropriate water management in order to reduce human and animal exposure to such pathogens.

 The aim of present study was determination of occurrence of Listeria Listeria spp. in various point of a municipal wastewater treatment plant. 

 The samples were collected of influent, effluent, raw sludge, stabilized sludge and dried sludge from north wastewater treatment plant Isfahan, Iran. The presence of Listeria spp. was determined using USDA procedure and enumerated by a three-tube most probable number assay using Fraser enrichment broth. Then, biochemically identified Listeria monocytogenes was further confirmed by PCR amplification. 

 L. monocytogenes, L. innocua and L. seeligeri were isolated from 76.9%, 23.1% and 23.1% of influent, 38.5%, 46.2% and 7.7% of effluent, 84.6%, 69.2% and 46.2% of raw sludge, 69.2%, 76.9% and 0% of stabilized sludge and 46.2%, 7.7% and 0% of dried sludge samples, respectively. The efficiency of wastewater treatment processes, digester tank and drying bed in removal of L. monocytogenes were 69.6%, 64.7% and 73.4%, respectively. All phenotypically identified L. monocytogenes were further confirmed by PCR method. 

 Application of sewage sludge in agricultural farms as fertilizer may result in bacteria spreading in agriculture fields and contaminated foods with plant origin. This may cause a risk of spreading disease to human and animals. Using parameters such as BOD 5 is not sufficient standard for the elimination of pathogenic microorganisms.

Aims : 

The aim of this study was to measure the concentration of Pb, Cd, and Ni in the effluent of Isfahan north wastewater treatment plant as well as in the soils and agricultural products irrigated with that effluent. 

 In the selected area around of the treatment plant, treated wastewater, soil, wheat, wheat stem, and corn were sampled. The samples were digested with nitric acid procedure and analyzed with a flameless atomic absorption spectrometer. 

 The results shows the average concentration of Pb, Cd, and Ni was 0.02, 0.006, and 0.062 mg/1 in the effluent; 13.9, 1.67, and 2.23 μg/g in the deep soil; 0.366, 1.02, and 0.79 μg/g in the wheat; 0.67, 0.86, and 1.32 μg/g in the wheat stem; and 6.37, 0.62, and 0.52 μg/g in the corn, respectively. 

 The average concentration of Pb, Cd, and Ni were less than the critical limits in the effluent (0.01, 0.2, and 5 mg/1) and the amounts were currently within the permitted range for soil (2-100, 10-1000, and 10-7 mg/g). In some farming lands, the amounts were beyond the permitted range for plants (1-10, 1-10, and 0.2-0.8 mg/g). There was a meaningful relationship between the average concentration of these metals and the kind of sample. In addition, the accumulation of heavy metals in all samples irrigated with wastewater was more compared to samples irrigated with groundwater. So irrigation of farmland with effluent should be monitored. Farmers in the area must be advised to grow shrubs with smaller roots rather than big-rooted plants like sugar beet.

Contamination of drinking water sources with nitrate may cause adverse effects on human health. Due to operational and maintenance problems of physicochemical nitrate removal processes, using biological denitrification processes have been performed. The aim of this study is to evaluate nitrate removal efficiency from drinking water using autotrophic denitrifying bacteria immobilized on sulfur impregnated activated carbon in a fluidized bed bioreactor. After impregnating activated carbon by sulfur as a microorganism carriers and enrichment and inoculation of denitrifying bacteria, a laboratory-scale fluidized bed bioreactor was operated. Nitrate removal efficiency, nitrite, turbidity, hardness and TOC in the effluent were examined during the whole experiment under various conditions including constant influent nitrate concentration as 90 mg NO3--N/l corresponding to different HRT ranging from 5.53 to 1.5 hr. We found that the denitrification rates was depended on the hydraulic retention time and the nitrate removal efficiency was up to 98% and nitrite concentration was lower than 1mg/l at optimum HRT=2.4 hr respectively. Moreover, there was no difference in hardness between influent and effluent due to supplying sodium bicarbonate as carbon source for denitrifying bacteria. However pH, TOC, hardness, and turbidity of the effluent met the W.H.O guidelines for drinking water. This study demonstrated that an innovative carrier as sulfur impregnated activated carbon could be used as both the biofilm carrier and energy source for treating nitrate contaminated drinking water in the lab-scale fluidized bed bioreactor.

Cyanide is a highly toxic compound which is found normally in the wastewater of numerous industries, such as Electroplating. The release of this compound into the environment has a lot of health hazards. The Purpose of this study was to compare the electrochemical oxidation efficiency with chemical precipitation method for cyanide removal from industrial wastewater. This study was conducted experimentally in a pilot system. In this study, the optimum conditions such as pH, Fe/CN- and reaction time were investigated in the Ferrous Sulfate precipitation method for cyanide removal from wastewater of electroplating industries by the use of jar test. It also investigated the effect of pH, voltage and operation time for total cyanide removal by electrochemical oxidation method by applying a stainless steel as an anode and copper as a cathode. And finally, the efficiency of two methods was compared. In the Ferrous Sulfate Precipitation method, the optimal conditions were obtained for the removal of cyanide at (pH 6/5, and 10:1 Molar Ratio and Operation Time 60 minutes). In these conditions, the removal efficiency was 93 percent. In the electrochemical method, the optimal conditions were obtained at the voltage of 9V and pH=13 and the operation time of 90 minutes in which the average percentage removal of cyanide was about 88 with SD=2.43. The results statistically confirmed the significant relationship between cyanide removal efficiency and optimal conditions in both methods (p< 0.05). But comparison of the two methods showed that the cyanide removal efficiency in the electrochemical method was as much as the chemical precipitation method. Due to the high cyanide removal efficiency and achieving the standards for effluent disposal to the environment, it seems that ferrous Sulfate precipitation method is more useful.

crude oil is a very complex composition that contains thousands of hydrocarbons with different structure. Many compounds in crude oil if entering in drinking water can harmful to on human health. Use of bioassay method for assessment effect of purification process has considered for useful results. The effect of ozonation and powdered activated carbon separately and combination for reducing the toxicity of crude oil from water has been investigated. for toxicity test, different concentrations of water soluble fraction of crude oil added in water and larvaes of rain bow trout were used. Before and after ozonatiopn and adding powder activated carbon, TOC and bioassay test were performed. Probit test was used for analysis the result and determination of LC50. it was found Ozonation and activated carbone were effective on decreasing the toxicity and TOC.The result also shawed that the use of activated carbon for reducing the toxicity and TOC were more effective than ozonatiuon. The result showed that ozonation with 1 and 10mg/L would increase LC50 98h from 60 to 113.3 and 205.5 mg/L. At the some sample TOC concentration changed from 54.98 to 42.8 and 205.5 mg/L. LC50 96 h in the samples after add of different concentration of PAC was, 94.8, 106.6, 117.8, 138.3 and 181.5 mg/L. Ozonation of sample perior the luse of activated carbon, increasing the adsorbtion rate and resulted in more decreasing in the TOC and toxicity.

Phenolic compounds have become a cause for of worldwide concern due to their persistence, toxicity and health risks. Hence, removal of these pollutants from aqueous effluents is an important practical problem. Ultrasonic technology may be used for water and wastewater treatment as an advanced oxidation process. Application of this technology, leads to the decomposition of many organic compounds during cavitation process. The degradation of 4-chlorophenol in aqueous solution under sonolysis at 45 kHz coupled with fFenton process was is investigated. The oxidation rate was influenced by many factors, such as the pH value, the amount of hydrogen peroxide, catalyst (FeSO4) and initial p-chlorophenol concentration. The experimental results showed that the decomposition of p-chlorophenol was affected by the various reaction conditions. The optimum conditions obtained for the best degradation rate were pH=3, H2O2 concentration of 0.05 mol/L and 0.025 mmol/L for catalyst, respectively. Also it was observed that the degradation of p-chlorophenol depended on its initial concentration.

 This study was conducted for degradation of 4-chlorophenol by microwave (MW) radiations alone and in combination with hydrogen peroxide from aqueous solution. 

 A modified domestic microwave oven was used alone and in combination with hydrogen peroxide for removing 4-chlorophenol. Furthermore, the influences of pH value, irradiation time, the power of MW radiations, and the initial concentration of 4-chlorophenol were studied. 

 It was shown that 4-chlorophenol removal efficiency extremely depend on the concentration of hydrogen peroxide, pH value, MW irradiation power and initial 4-chlorophenol concentration. The optimum conditions obtained for the best degradation rate were pH = 10.5, H 2 O 2 concentration of about 0.1 mol/l, and MW irradiation power of about 600 W. Other result shows that the best degradation rate of 4-chlorophenol was obtained when initial 4-chlorophenol concentration was 50 mg/l. Also the amount of the specific energy consumption in this method was 17460 kwh/kg of the removed organic compound. 

 This result shows that MW irradiation in the presence of hydrogen peroxide can greatly enhance the degradation of 4-chlorophenol. However, the high consumption of energy for this method must be taken into consideration.

Partial nitrification was reported to be technically feasible and economically favorable, especially for wastewater with high ammonium concentration or low C/N ratio. In this study, the effect of dissolved oxygen (DO) and influent ratio of chemical oxygen demand to nitrogen (COD/N) ratio on biological nitrogen removal from synthetic wastewater was investigated. Experiments were conducted in moving bed biofilm reactors (MBBRs) on partial nitrification process in pilot-plant configuration for 300 days. DO levels were changed from 0.04 to 0.12 and 0.42 to 3.4 mg/l in the anoxic (R1) and aerobic (R2) reactors, respectively. The optimum DO for partial nitrification was between 1-1.5 mg/l in the aerobic reactor (R2). Influent COD/N ratios between 20 and 2 g COD/g-N were tested by changing the nitrogen loading rate (NLR) supplied to the pilot plant. During operational conditions when the DO concentration in aerobic reactor was above 1 mg/l, near complete organic carbon removal occurred in the total MBBRs system. The effluent total nitrogen concentration in the operational conditions (1.7-2.1 mg O2/l and NH+4-N=35.7 mg N/l) was obtained in the range of 0.85-2 mg/l. The highest nitrite accumulation (50%-52%) took place at the DO concentration of 1-1.5 mg/l and increased with decreasing COD/N ratio in aerobic reactor (R2). This study showed that the average nitrification rate at various COD/N ratios is about 0.96 gN/m2 per day while the maximum nitrification rate is about 2 gN/m2 per day at COD/N ratios lower than 6. The experimental COD/N ratio for denitrification was close to complete sum of NO2- and NO3- (NOx) removal efficiency (about 99%) at COD/N ratio equal 14 in the operational conditions in the anoxic reactor (R1).