فهرست مطالب ehsan aghayani

 The development of the automobile industry has caused various pollutants to enter the environment, one of which is fluoride. Therefore, this study aims to improve the fluoride removal from wastewater pre-paint units of the automotive industry to achieve discharge standards to surface waters.

 The study is descriptive and on an applied scale, which has been carried out to compare the efficiency of the chemical coagulation process using lime and alum, as well as the electrocoagulation process using aluminum anodes in the presence of lime to remove fluoride.

 The results of real wastewater characteristics showed that the pH of wastewater is in the range of 6.1 to 6.3, and its fluoride concentration is in the range of 45 to 55 mg/L. The results of the experiments show that in the most optimal possible state in the chemical coagulation process, it is possible to achieve fluoride removal efficiency in the range of 76 to 81 percent. However, the removal efficiency in the electrocoagulation process using an aluminum anode at a concentration of 5 mol/L of calcium ions, and current density of 20 A/m2 after reaction time of min 20 to 99% can also be achieved.

 Considering the high fluoride removal rate (more than 99%) in the electrocoagulation process in the presence of calcium ions, this process can be introduced as an efficient technology for fluoride removal.

Heavy metals in water can pose risks to human health. Therefore, it is necessary to monitor and measure metals to ensure the health of consumers.

This study aimed to measure heavy metals such as arsenic, lead, cadmium, chromium, zinc, and mercury in water resources and urban water distribution networks in spring and summer of 2021 in Maragheh city. Accordingly, 25 samples were taken to investigate the presence of heavy metals. The presence of these metals in water sources was investigated using qualitative maps and finally, by evaluating the health risk caused by the presence of these metals, their effect on the health of consumers has been studied.

Examining the concentration of metals in water resources upstream of the dam shows a relatively high concentration of metals, especially arsenic (13.2 µg/L). Despite this, the amount of arsenic after the water treatment plant and in the distribution network is reduced to an insignificant level. On the other hand, the results show that the amount of zinc metal in the network is higher than in the reservoir of the dam, and its concentration in the dam is equal to zero and in the network, it reaches the highest value of 578 µg/L. Finally, the health risk assessment shows that the calculated THI values for all samples vary between 0.01 and 0.99.

Based on the calculated health risk, there is no threat to the health of consumers regarding heavy metals in Maragheh drinking water. Also, these results double the necessity of additional studies regarding the leakage of zinc metal from the pipes and accessories of the city's drinking water distribution network in the future.

Although anaerobic system has been successfully used for treating the strong industrial wastewater, its efficiency for low-strength wastewater as municipal wastewater is not satisfying. This study aimed to enhance the capability of an anaerobic baffled reactor (ABR) for treating municipal wastewater. A 7-L ABR with 5 compartments was operated for a 287-day period fed with primary effluent from a wastewater treatment plant at 17 to 19°C. The study was conducted in 2 phases. In the first phase, the performance of ABR and in the second phase, the performance of ESABR (ABR integrated with an electrochemical system) were investigated. The results of ABR operation indicated that at hydraulic retention time (HRT) =24 hours, the average removal efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total Kjeldahl nitrogen (TKN), total phosphorous (TP), and log reduction value (LRV) of coliforms were obtained to be 71%, 75%, 79%, 23%, 30.3%, and 5.8 Log, respectively. In this phase, when the HRT was decreased from 24 to 18 hours and from 18 to 14 hours, the removal efficiency of all parameters by the ABR was decreased. After the shift of ABR operation to ESABR, at HRT=24 hours and current density of 0.78 mA/cm2, the performance of the reactor was enhanced, so that the removal efficiency of BOD, COD, TSS, TKN, TP, and LRV of coliforms were achieved 16.8%, 15%, 4%, 10.7%, 49%, and 1 Log, which was greater than those obtained by ABR. According to the results, this technology (SEABR) is suitable for treating the low-strength municipal wastewater.

Textile industry is one of the largest consumers of water in the world. The wastewater from the textile industry is known to have strong colour, chemical oxygen demand (COD), highly fluctuating pH and high temperature. The release of coloured wastewater represents a serious environmental and public health concern. Among the various physicochemical and biological methods of textile wastewater treatment, coagulationflocculation is considered as an attractive and favourable technique because of its low cost, easy operation and high efficiency.
The study was conducted in the laboratory scale using Jar test. Dye removal from real wastewater was investigated by the use of three mineral coagulants including poly aluminum chloride, ferric sulfate and ferric chloride. In order to optimize the process, parameters including pH, coagulant dose, time and speed of coagulation were considered. Treated samples were analysed to determine the residual color and COD.
According to the results of our experiments, under optimum conditions of process (pH 9, doses of 250 mg/lcoagulant and coagulation speed of 175 rpm with a duration of 5 minutes), the highest removal efficiencies (COD 44.4% and color 95%) were obtained by the use of poly aluminum chloride. The results showed that poly aluminum chloride enhanced the biodegradability of wastewater from 0.07 to 0.21 at optimized process conditions.
Although the coagulation process reduced a large percentage of pollution load in the wastewater, another process has to be followed to meet the wastewater discharge standards in receiving sources.

The vacuum UV (VUV) system is a novel chemical-less advanced oxidation processes (AOP) used to decompose different class of organic contaminants. The present study aimed at investigating the efficiency of VUV process to degrade toluene as a model of aromatic hydrocarbons from the gas stream in a bench-scale photo-reactor.
The effect of various parameters including radiation flux, relative humidity, toluene concentration, and ozone dosage were investigated on toluene degradation in the VUV process.
The results showed that increasing the relative humidity up to 45% could considerably accelerate the oxidation of toluene as compared with the dry air stream in the process. Complete destruction of toluene was reached at radiation fluxes of 0.366 and 0.732 mJ/cm2 for 5 and 15 ppm of toluene, respectively. Dosing ozone into the VUV photo-reactor at the dosages of 20, 40 and 60 μg/s led to improve the toluene degradation from 65.6% to 100%. The removal of toluene in the VUV process under the selected optimum conditions followed a pseudo-first order reaction model with the degradation rate values of 5.99 mg/L.min.
It was found that VUV process might be a novel and emerging AOP, which can efficiently perform for decomposition of aromatic hydrocarbons in contaminated air stream.

Carbon footprint is a set of greenhouse gas emissions from a service or product throughout their lifespan, and a scale for measure the impact of human activities on the environment. In this study, the carbon footprint of Abyek cement plant was measured. the carbon footprint measurements in Abyek cement plant (by Testo 350 XL) and finally reduction strategies were developed. Sampling methods based on US EPA and environmental protection agency in Iran methods. Results Based on the results of this study, the temperature and velocity outlet gas is effective on the carbon footprint of the plant. As the outlet gas temperature increases, speed increases too, thus, increase the amount of carbon footprint. Based on equations IPCC, emission rate from plant is about 412674 tons as carbon dioxide per year. The amount per hour is 47109 kg as carbon footprint approximately. This study showed that the detection process can be created short route for codify contrast policies to deal with greenhouse gases. Because carbon dioxide is not a pollutant gas, thus, national and international standards is not defined for its.

Background and Municipal wastewater treatment plant effluents are amongst the main available water sources. Reuse of these effluents requires further standards beyond secondary standards. Therefore, removal of organic pollutants and some compounds such as nitrate and phosphate from effluents should be done at a greater extent. In this study, removal of these compounds from secondary effluent was examined using an absorbent of iron oxide nanoparticles (MNPs Fe3O4).
The research was carried out using actual effluent of urban wastewater treatment plant in laboratory scale. The iron oxide nanoparticles (MNPs Fe3O4) was used for removal of target pollutants by investigating different parameters such as pH, initial concentration, contact time, and adsorbent dosage using optimization of one factor at a time. Afterwards, the optimum condition was determined by adsorption and kinetic isotherms.
The average BOD5, COD, nitrogen, and phosphorus in wastewater treatment plant effluent were found to be 25, 43, 63 and 8.6 mg /L, respectively. The optimum conditions for adsorption of these pollutants by Fe3O4MNPs were obtained at pH 3, 15 min contact time and absorbent dosage of 1 g/l. Removal of PO43-, NO-3, BOD5 and COD in the optimum condition was obtained to be 54, 11.5, 56, and 75%, respectively, and the maximum adsorption capacities for target pollutants were 4.7, 1.6, 14, and 32 mg/g. The results showed the adsorption by Fe3O4 followed the Freundlich model and pseudo first-order kinetic for COD and PO43- and pseudo second-order kinetic for BOD5 and NO-3 removal.
Iron oxide nanoparticles (MNPs Fe3O4) is suitable for removal of some pollutants (COD, BOD5 and PO43-) from the secondary effluent, but this absorbent is not effective for nitrate removal.

The use of various additives containing lead compounds in the production of thermoplastic tubes and the growing use of these materials in plumbing and water distribution systems, it has increased concern release metals like lead in drinking water. Lead is a neurotoxic metal. The aim of this study was evaluation of the probability of water pollution due to lead leaching of thermoplastic pipes in drinking water distribution networks. In this study two un-plasticized polyvinyl chloride pipes (entitled UPVC 1, 2) and a polyethylene(PE) pipe were Investigated using locally manufactured pipes and with a length of 50 cm. the effects of pH, alkalinity, chloride /sulfate mass ratio, total dissolved solids and water temperature were studied on thermoplastic tubes. This study showed that the effect of the parameters on UPVC1 tubes were measured less than the standards. The release of lead in The PE pipe from the effect of pH and dissolved solids were measured over the standard (EPA). The release of lead in The UPVC2 pipes from of different concentrations of pH, chloride/sulfate mass ratio, temperature were measured over the standard (EPA) and guidelines (WHO) and national standards. Statistical analysis of the results showed that lead release of tubes are significant and have reliability in probability of 95% (p ≤ 0.05). By attention to effect of chemical parameters on the release of lead and importance role of the thermoplastic pipes in distribution of water system, to protect the health of society, authorities’ surveillance is necessary on the thermoplastic pipe plants.

Natural organic matter is the cause of many problems associated with water treatment such as the presence of disinfection by-products (DBPs) and membrane fouling during water filtration. In this study, the performance of the peroxi-electrocoagulation process (PEP) was investigated for the removal of humic acids (HAs) from aqueous solutions. PEP was carried out for the removal of HA using a plexiglas reactor with a volume of 2 L and fitted with iron electrodes and a direct current supply (DC). Samples were taken at various amounts of pH (2-4), current density (1 and 2A/cm2), hydrogen peroxide (50-150 mg/L) and reaction time (5-20 minutes) and then filtered to remove sludge formed during reaction. Finally, the HA concentration was measured by UV absorbance at 254 nm (UV254). Results indicated that increasing the concentration of H2O2 from 50 to 150 mg/L increased HA removal efficiency from 83% to 94.5%. The highest removal efficiency was observed at pH 3.0; by increasing the pH to the alkaline range, the efficiency of the process was reduced. It was found that HA removal efficiency was high in current density 1A/cm2. Increasing current density up to 1 A cm-2 caused a decrease in removal efficiency. Results of this study showed that under the optimum operating range for the process ([current density] = 1A/cm2, [hydrogen peroxide concentration] = 150 mg/L, [reaction time]= 20 minutes and [pH]= 3.0), HA removal efficiency reached 98%. It can be concluded that PEP has the potential to be utilized for cost-effective removal of HA from aqueous solutions.

Parachlorophenol has an extended usage in refineries, petrochemical industries, insecticide, and herbicide manufacturing industries. Tire a solid waste, which is disposed in large amounts each year, a large number of them in landfills can cause irreparable environmental impacts. Consequently lots of efforts were done to produce activated carbon from used tires. Activated carbon was made in laboratory conditions by using pyrolysis furnace. Scanning electron microscopy was used for determining structural characteristics of the activated carbon produced from recycled used tires and Brunauer, Emmett, and Teller isotherm was used to find out its special surface. The structure of produced activated carbon in this study has a special surface of 111.702 m2/g. The internal diameter of holes was 1.54 nm, and the total volume of them was 0.124 ml/g. The removal efficiency was reduced from 88.59% to 69.25% by changing the pH from 3 to 9. In addition, the efficiency was reduced from 88.59% to 75.95% when the primary concentration of parachlorophenol increased from 10 to 60 mg/L. On the other hand, changing the temperature from 10° C to 30° C increased it from 65.86% to 74.53%. Moreover, contact time had direct impacts on the removal efficiency. The results conform Freundlich isotherm (R2 = 0.9958). The efficiency of parachlorophenol removal would be decreased by increasing pH and concentration of the pollutant, and would be increased by adding temperature and contact time. As a conclusion, since the recycled tires are cheap, the produced activated carbon from them can be used as an effective and low-cost method for parachlorophenol removal from aqueous solutions.

A wide range of coagulants، oxidants، and disinfectants are used for water and wastewater treatment. Ferrate ion as a strong oxidant has the highest oxidation potential among all oxidants and disinfectants in water and wastewater treatment. Ferrate (VI) ions are reduced to Fe (III) ions or hydroxide ferric in water، which can simultaneously serve as a coagulant and oxidant or a disinfectant in a versatile process. The aim of this study was to determine the effectiveness of potassium ferrate use for advanced treatment of sewage. This quasi-experimental study was conducted in laboratory scale. An advanced wastewater treatment was studied by potassium ferrate on the effluent wastewater through determining the effect of pH and concentration on the removal of turbidity، the chemical oxygen demand (COD) and phosphorus. In order to determine the efficiency of disinfection of the ferrate، the effect of three varables، contact times، ferrate concentrations، and pH on disinfection processes was determined by the most probably number index (MPN). The results showed that the best condition for COD removal efficiency and the removal of turbidity was %65 and %90 using potassium ferrate with pH=5 and optimum concentration of 10 mg/l. pH and concentration of potassium ferrate for optimum performance of phosphorus removal was 5 and 12 mg/L، which caused phosphorus removal %72. The optimum condition for potassium ferrate applied as disinfectant was in 4/mg/l concentration، contact time of 25 minute، and pH=6. Potassium ferrate can be used as an effective oxidant، disinfectant and coagulant chemical for treating a variety of municipal and industrial wastewaters. It will allow access to multiple targets in a process.

The olive oil mill wastewater is one of the contaminating food industrial wastewaters. Olive oil extraction process imports wastewater with high phenolic chemicals into the environment. In this study the toxicity of raw olive oil mill wastewater and the effluent of electro-coagulation have been investigated. Germination test was used for evaluating the toxicity of wastewater and effluent process. Electro-coagulation-flotation examinations performed in a plexiglas electrochemical reactor with 1750 ml practical volume. 4 blades of aluminum and titanium as anode and cathode electrodes with a gap of 2 cm were connected to DC power supply in monopolar parallel mode. Based on the information from this study, the pollution load of phenolic compounds in olive oil mill wastewater is 1000 times more than municipal wastewater. Also, the evaluation toxicity of effluent obtained from the process in natural pH of wastewater (pH=5.2), 117 mA/m2 current density and 30 minutes time process, suggests that the effluent causes plant species growth, even without dilution. The results obtained from this research can warn us to the risks of releasing these wastewaters without treatment and toxic effects on the different species of plants. Results demonstrated although using of electro-coagulation-flotation process removes high percent of pollutants of olive oil mill wastewater, but, it can’t attain the discharge limitations, then it should be more treated with some other methods.