Nitrate removal from drinking water by ion exchange and reverse osmosis
Amir Hesam Hasani*
Mehrnoosh Samak Abedi*
*Faculty of Environment,
Science and Research Branch, Islamic
Key words: nitrate, drinking water, ion exchange, reverse osmosis
Nitrate is one of the major components which is known as a chemical pollutant indicator in water and can be removed by physico-chemical and biological methods.
In this study, ion exchange and reverse osmosis processes were studied for nitrate removal.
The reverse osmosis system used in this research contained a TFC membrane with the capacity of 300 l/day, a pressure tank, and micro filters measuring 1 and 5 micrometers.
Synthetic nitrate solutions with concentrations of 25, 50, 100, 200 mg/l were injected into the system at a fixed amount of TSD.
The ion exchange column was made of plexy glass with a volumetric rate of 15 BV/hr.
Nitrate with concentrations of 25, 50, 100 mg/l and different amounts of TDS (400, 700, 1000 milligrams per liter) were injected into the column.
The study lasted for 8 months and the following results were obtained:
-- An increase in nitrate concentration causes a decrease in efficiency from 93.5 to 82.5 percent for the reverse osmosis and from 99.7 to 95 percent for the ion exchange.
-- An increase in TDS has a negative effect on efficiency so that the removal efficiency changes from 99.7 to 83 percent in the ion exchange.
--An increase in the other anions like sulfate causes a decrease in efficiency in the ion exchange system.
--The regeneration solution has an effect on the operation of the ion exchange system. The best removal efficiency is about 99.7 percent, observed at a TDS of 400 when resin is regenerated by sodium hydroxide.
--The highest removal efficiency belongs to the nitrate concentration of 25 milligrams per liter and a TDS of 400 milligrams per liter in both methods: 99.8 percent for the ion exchange and 93.5 percent for the reverse osmosis systems.
Identification of parameters influencing hexavalent chromium mist measurement using Taguchi experimental design
Farideh Golbabaei *
Seyed Jamaleddin Shahtaheri*
* Department of Occupational Health,
of Epidemiology and Biostatistics, School of Public Health and
Key words: hexavalent chromium mist, mist, electroplating, Taguchi experimental design
Hexavalent chromium, Cr+6, has been classified as a human respiratory carcinogen. Many workers in different industrial fields, mainly chromium electroplating, are exposed to this chemical. So, there has been a considerable interest among industrial hygienists in assessing Cr+6 concentrations accurately. Since Cr+6 is relatively unstable and is likely to decrease during sampling and sample storage and analysis, it is necessary to determine the effective factors which influence Cr+6 mist sampling. Therefore, this study was carried out in order to determine the major parameters influencing Cr+6 mist sampling method, using Taguchi experimental design. A chromium electroplating bath was used to produce homogeneous mist and a total of 24 Cr+6 mist samples were collected using the U.S. National Institute for Occupational Safety and Health method 7600. The results revealed that Cr+6 concentration was higher: (1) for sampling by closed-face filter cassettes than for sampling by open-face filter cassettes (P <0.05); (2) for samples collected at 35 cm above the electroplating solution surface than for samples collected at 50 cm (P <0.001); (3) for sampling duration of 30 minutes than for sampling duration of 180 minutes (P <0.001); and, (4) for samples extracted immediately after sampling than for samples with delayed extraction (24 hours after sampling) (P <0.001).Taguchi test results showed that the optimal conditions for Cr+6 measurement were as follows: sampling at a height of 35 cm, sampling duration of 30 min, immediate sample extraction, and sampling with closed-face filter cassettes. Under these conditions, the highest Cr+6 concentrations would be collected and the highest degree of confidence could be obtained.
Calculation of external costs of road transportation on social environment (with an emphasis on road accidents)
Transportation Research Institute, Ministry of Roads and Transportation, IR_BEH@YAHOO.COM
Abdolreza Rezaee Arjroody
Transportation Research Institute, Ministry of Roads and Transportation, REZAEEAR@YAHOO.COM
Key words: road accident, external cost, DALY, V.S.L.
Accident costs are either internal
or external. The external costs include the value of human life and the negative
economic impacts of disabilities and mental injuries. In this paper, the external
costs of death and disability in
In order to quantify the accident
impacts on health, DALY (Disability Adjusted Life Year) indicator was employed.
This indicator is used to measure the state of population health (with regard
to cost-effectiveness) and is the only quantitative indicator for the
calculation of the external costs of death, disease, and disability, and
indicates the number of years lost as a result of premature mortality, relative
disability, and the like. Then, the monetary value of each DALY was determined.
Finally, the external costs of road accidents for
Detergent removal from car manufacturing
industrial wastewater and its standardization
Amir Hossein Javid*
Sayyed Ahmad Mirbagheri
Faculty of Civil Engineering, K.N.T.University
*Faculty of Energy and Environment, Science and Research Branch, Islamic
Key words: industrial wastewater, detergent, surfactant, car manufacturing industries.
Car manufacturing industries are considered as one of the most important environmental pollutants and this is mainly due to the high concentration of detergents in their wastewater. Because of their components, detergents have different effects on the environment such as causing Eutrophication, being harmful to the aquatics, reducing mobility among fishes, and inhibiting enzyme reactions. Therefore, the removal of these compounds from the car manufacturing wastewater is very important. It is to be mentioned that all these industries try to have a more efficient industrial wastewater treatment plant at lower costs.
This study aimed at finding the best method for detergent removal by determining the effect of such processes as flocculation and coagulation, detergent oxidation using Fenton method, and reverse osmosis.
The above-mentioned methods were used for the wastewater of an Iranian car manufacturing company (Iran-Khodro) and the results of pilot experiments and laboratory analyses show that the reverse osmosis, as a physical method, can remove detergents with 95% efficiency. The results also show that the removal efficiency of Poly Aluminum Chloride (PAC) in coagulation and flocculation process was 84% in pH=6 and 45 mg/l dosage.
The capability of Anodonta cygnea (Unionidae)
in the biological treatment of urban wastewater
(an open system approach)
Faculty of Natural Resources,
Faculty of Energy and
and Research Branch, Islamic
Key words: wastewater treatment, filtration rate, Anodonta cygnea, phosphate and nitrate, Chlorella sp., Scenedesmus sp. Algae
Agricultural and industrial sewages affect the quality of water everywhere and the dissolved phosphate and nitrate in such wastewaters create many environmental problems.
This study aims at reducing the dissolved components of wastewater using biological methods instead of the chemical ones. The swan mussel (Anodonta cygnea) is one of the most famous fresh water suspension feeders and seems to be an active agent for the removal of suspended particles and bacteria from water resources.
To see whether A. cygnea is capable of reducing the nitrate and phosphate dissolved in urban wastewater, a number of them were placed in an open system at 19 - 20º C. Their filtration rate (ml. min-1. g -1 (Ash Free Dry Weight (AFDW)) and the retention rate of the dissolved phosphate and nitrate salts were measured. The volume of the water passed through the gills was calculated with the help of dixenic culture of Chlorella sp. and Scenedesmus sp. The algae developed in Guillard and Rhyter media and were used when their concentration reached about 400. 103 cells. ml-1.
The results show that when fresh algae increase in number to meet their vital needs, they are capable of removing a considerable amount of the dissolved materials. The dissolved nitrate tended to decrease from 204.17 mg.L-1 to 140.42 mg.L-1, and the filtration rate was about 10.01 ml.min-1.g-1 Ash Free Dry Weight (AFDW) during 20 minutes in the open system.
Moreover, it turned out that there was a positive correlation between the weight and the specific filtration rates of mussels. While weight increased from 2.02 gr to 2.14 gr (AFDW), specific processed water also increased from 5.87 ml.min-1.g-1 AFDW to 10.01 ml.min-1.g-1 AFDW (p< 0.003). Furthermore, the results showed that an increase in the pollutants’ concentration resulted in an increase in the specific filtration rate by mussels. When nitrate increased artificially (by adding nitrate salts) from 84.53 mg.L-1 to 204.17 mg.L-1 in the inputs of the two experiments, the specific filtration rate increased from 5.87 ml.min-1.g-1 AFDW to 10.01 ml.min-1.g-1 AFDW and the nitrate concentration observed in the outputs from 66.97 mg.l-1 to 140.42 mg.l-1 (p<0.001). In the case of phosphate salts, their concentration decreased from 60.49 mg.L-1 to 40.35 mg.L-1 and the filtration rate was 10.83 ml.min-1.g-1 AFDW during 20 minutes. Meanwhile, the specific filtration rate increased from 3.84 ml.min-1.g-1 AFDW to 10.83 ml.min-1.g-1 AFDW (p<0.037) when body weight increased from 2.02 to 2.14 gr. The results also showed that when dissolved phosphate increased artificially (by adding Phosphate salts) from 20.74 mg.L-1 to 60.49 mg.L-1 in the inputs of the two experiments, specific filtration rates increased from 3.84 ml.min-1.g-1 AFDW to 10.83 ml.min-1.g-1 AFDW and the phosphate concentration observed in the outputs were 17.81 mg.l-1 and 40.35 mg.l-1 (p<0.014). Based on the obtained results, Anodonta cygnea can be considered as a natural purifying agent in the treatment of urban wastewaters. The results of this study can practically be used in other experiments.
The concentration and sources of heavy metals
the sediments of
Marjaneh Kharrat Sadeghi
Qaemshahr branch, Islamic Azad University
Key words : pollution, heavy
metals, chemical partitioning,
This study aims at determining
the anthropogenic and lithogenic sources of heavy metal pollution in
Determination of recreational value of Anzali wetland
using the travel cost method
Faculty of Energy and
and Research Branch, Islamic
Key words: Anzali wetland, evaluation, travel cost method
Anzali wetland with an area of about 200 km is
situated in the southern margin of the Caspian Sea and bordered by the cities
This study is to determine the recreational value of Anzali wetland using the regional travel cost method so that the results can be used as an effective tool for the planning and management of development projects.
This method is based on estimating the relationship between the number of visitors to a resort and its distance from their dwelling places and the average of their travel costs.
To this end, assuming the wetland as the center, 6 semicircles with a fixed distance of 300 km from each other were drawn so that they would cover all over the country. Then, using a map and the existing statistics, the area and the population of any of these regions were calculated. In the next step, the socio-economic data extracted from the questionnaires completed by the visitors were analyzed. Then, considering the available data, the diagram showing the relationship between the travel cost and the number of visitors to this resort was drawn. After that, the different entrance fees were added to the total access costs, the new ratio of the visitors was obtained, and the curve of demand for Anzali wetland was drawn. Finally, by estimating the area under the demand curve, the daily recreational value of Anzali wetland was calculated to be 124,504,000 Rls., which shows the high recreational value of this wetland. The data show that most of the visitors of Anzali Wetland are 30-39 years old and the majority of them are high-school graduates and university students. Moreover, as visitors’ income increases, they decrease in number.
The effect of road and railway transportation on wildlife
Borhan Riazi *
Neamatollah Khorasani **
Mahmood Karami **
Banafsheh Houshyardel *
*Faculty of Energy and Environment, Science and Research Branch, Islamic Azad University
**Faculty of Natural Resources,
Key words: road, railway, wild life, impact
Abstract Biological environment, especially the wildlife, has seriously been affected by road and railway construction projects. The studies done on natural ecosystems in recent decades introduce roads and railways as factors that threaten the wildlife through the destruction and fragmentation of their habitats and preparing the grounds for overhunting and pollution.
For the animals whose habitats are in roadsides, noise pollution causes disorders in their hearing so that they cannot do their biological activities well. Meanwhile, they suffer from air pollution which leads to respiratory problems and other biological disorders. If the mitigation measures suggested in this article are employed, these difficulties can be decreased. Generally, roads have more negative effects on the wildlife than the railways. The main problems of roads are: the salt that is used for deicing the road surfaces, increasing access to the natural ecosystems, and as a result, destruction of the environment and hunting of the animals, use of warm surfaces of the roads -- specially by reptiles -- and attraction of animals to the road by car lights at night.
Convention on Environmental Impact Assessment in a Transboundary Context (
*Faculty of Energy and
Environment, Science and Research Branch, Islamic
Key words: environmental problems with a
tranboundary nature, environmental impact assessment,
If environmental considerations are taken into account in the development plans performed by the bordering countries, the adverse impacts on this ecosystem will be prevented.
present, the only legal framework for environmental cooperation among these
countries is the Convention for the Protection of the Marine Environment of the
Caspian Sea or Tehran Convention signed by all Caspian littoral states in
International efforts to reduce adverse transboundary environmental impacts, the importance of adopting prospective policies, and the necessity for improving international cooperation all resulted in the development of a Convention on Environmental Impact Assessment in a Transboundary Context (ESPOO). It is noteworthy that with the implementation of ESPOO Convention, some regional programs could reach agreement on reducing transboundary environmental impacts.
The economic and technical evaluation of
the electrical wind turbines in Boroojerd
Faculty of Management and accountancy, Branch, Islamic
Bureau of planning and economic studies, Iranian Atomic Energy Organization
Key words: electricity, energy, wind turbine, potential measurement, Boroojerd
Over the past few years, the average annual growth rate of electrical energy has been 8.29% and considering the high growth rate of electricity consumption in the current year, we should expect electricity shortages in the future.
One of the solutions to this problem is the use of small wind turbines for residential and commercial units, especially the ones far away from the electricity network.
In this study, economic and technical evaluation of a 5.5- KW wind turbine was carried out using the most advanced software for simulation and potential measurement.
In the end, the total obtainable energy and the benefits of the wind turbines were estimated.
Identification of environmental factors
determining the site of new cities in
Sayyed Masood Monavari*
of Envrironment, Science and Research Branch, Islamic
Key words: Mc Harg, site selection, criteria, ecological model, environmental
New cities established in every period of time anywhere have their own specifications, and most of their settlement impacts have produced many environmental problems.
In fact, new cities are built to meet certain requirements such as absorption of excess population, provision of dwelling, and many other needs, but no attention is paid to their origin in the process of sustainable development as far as environmental planning and design are concerned.
of many of the new cities in
this study, the location of Hashtgerd is assessed based on Mc Harg criteria and
on the ecological model of development for urban, rural, and industrial land
use. The results show that some environmental parameters such as slope, bed
rock, depth, structure of soil, and planting are considered appropriately in
selecting the site of the
results of the study also show that certain criteria such as air pollution,
water resources, soil, wildlife, and some infrastructures should be considered
as the main environmental criteria in the selection of the site for any