جستجوی مقالات مرتبط با کلیدواژه « treatment » در نشریات گروه « مهندسی آب »

Wastewater/runoff reuse is one of the strategies for sustainable water resource management which, based on the consumption type, requires supplementary treatment and standardization due to a wide range of environmental contaminations. Wastewater recycling not only reduces the pressure on fresh water resources but also is so frugal in comparison to the huge costs and the environmental and socioeconomic impacts of water transfer projects, especially between the basins. Nowadays, the application of bio-methods such as constructed wetlands has increased significantly due to the high cost of conventional wastewater treatment approaches. Constructed wetland systems have different design methods depending on the desired outlook (wastewater or runoff treatment). With regards to the flow patern, the system classifies into free water surface flow, and horizontal and vertical subsurface flow. Design configurations of the constructed wetlands depend on the kinematic description of biological reaction as well as the designer’s knowledge of the flow pattern. In this paper, the related literature is reviewed and the required supplementary treatment of secondary effluent of the treatment plant is presented. Then the performance of different types of constructed wetlands in removal of pollutants is investigated. Finally the principles of constructed wetlands design with the aim of harvesting and treating runoff and wastewater have been thoroughly described. The design criteria are presented based on the observed obstacles for such evolution in the field of water recycling. The feasibility of constructed wetlands is then investigated, especially in arid and semi-arid regions. By presenting the justified plan for the system application, the required measures for site selection of such constructed wetland systems are expressed.

Today the Phytoremediation is used as an effective and in expensive method for filtering water from contaminated areas. In this study, to absorb nickel two types of plants, Egyptian lotus and Cyprus alternifoliusare used. For this, ponds with Egyptian lotus and Cyprus alternifolius are used which nickel-ion concentrations are 2, 5, 10 and 15 mg/L and pHs are 5.5, 6.5, 7.5 and 8.5. The test temperature is constant at 25oC. The best absorption after 20 days was determined for Egyptian lotus plants at a concentration of 2 ppm and pH=5.5 and for the Cyperus alternifolius plant at a concentration of 2 ppm and pH=6.5. Adsorption isotherm studies with Langmuir and Freundlich models shows that nickel-ion adsorption behavior for Cyprus alternifolius and Egyptian lotusis followed by Freundlich and Langmuir isotherms respectively. Roots, leaves and stems analysis after nickel absorption with atomic absorption spectroscopy shows that for both plants roots have the most share as for Cyprus alternifolius and Egyptian lotus is 79.9 and 86.39 percent respectively.

The limited and vulnerable water resources in the world have a special economic value with social, economic and environmental impacts. Water resources constraints and the need for optimal use of these resources show the necessity and importance of using refined wastewater. In this research, the economic evaluation of the use of treated wastewater in Zahedan Green irrigation with economic and financial justification and focus on the environmental benefits of the wastewater treatment process are considered. Two scenarios are considered in this research: In the first case, according to the sales price of water equal to 3000 and 45000 Rials, an estimate has been made and in the second scenario, the environmental benefits and benefits of the project are estimated by estimating the shadow price of pollutants and pollutants from wastewater treatment. The data used in this study was based on spending patterns Water and Wastewater Company has been gathered Sistan and Baluchestan Province Zahedan is the location of the project. The findings of the study conducted in the first scenario show that the project is not justified in this scenario, the net value of the project over a period of 20 years and a 25 percent rate of return equal to -182.2065617 Rials as well as the benefit to cost ratio in this scenario is 0.68 times. In the second scenario examines reduce the environmental impact of wastewater treatment processes for the manufacture of shadow prices of undesirable and pollution control has been dealt with distance function. The average price shadow for adverse outcomes, including total biochemical oxygen demand, total chemical oxygen demand (BOD and COD) wastewater treatment ranged between 94-92 years, respectively -100.1, -319.75, -500.6 respectively. Shadow price to be interpreted that if we want the wastewater treatment plant and produce undesirable emissions (BOD and COD) reduce This will produce less than the desired output (treated water) or increased use of inputs in remediation and disposal of the product is desirable.

About 95 billion m3 of water is used all over the country every year, 1.8% of which is consumed in industrial sector. Sugar factories are among consumers with high water demands. In Iranian sugar factories, between 22 and 27 m3 of water is used per ton of sugarcane which is much higher than the world’s average which is about 11 m3 per sugarcane ton. Besides, the organic load in the wastewater of these factories is high. Therefore wastewater treatment and water reuse are essential for such factories. Water reuse is an effective solution to reduce the consumption of freshwater entry and prevent the environmental consequences. This study introduced a process of sugar production from sugarcane and analyzed the water consumption and feasibility of water reuse in different sections of the production process. Four main methods for reducing water consumption and wastewater production are: rainwater harvesting, using the humidity of sugarcane, water recycle and wastewater treatment and water reuse which are studied and important parameter in each case are introduced. In case of wastewater treatment, application of new methods of treatment such as aerobic granulation will be most efficient.

Application software and mathematical models in wastewater treatment processes combined with technical know-how precious time is to be.treatmen wastwater, in order to stabilize the organic matter in large and small communities done intermediate good water and sanitation can be considered the value is added and the resulting solid material reuse it to produce effluent standard and to strengthen the underground aquifers done, as part of this research using the analytic hierarchy process (AHP) and the work developed by the Expert Choice software relying on the experts compared the different processes were, of the five selected processes with weights WETLAND (0.399) and weight POND (0.351) BIOLAC with (0.108) and weight SBR process (0.085) and CAS weight (0.057) WETLAND option or Wetland with subsurface due weight should mention (0.399) has been chosen. in another part of the city of Shoushtar research using case study and review laboratory results,Confirmed that to design and build a wastewater treatment plant wastewater is important both quantitative and qualitative parameters and the financial comparison and evaluation processes of the study verified a first method (AHP) as a result, natural and semi-natural method because the process of being cheap and relatively quick return on investment with good efficiency Been selected.

Nickel is one of the heavy metals in the surface water that its Harmful effects can include bone and lung cancers, cyanosis, chronic headaches, dizziness, and chest pain and body weakness. This study has been performed to determine the efficiency of reducing nickel from aqueous environments by using carbon nanotubes. Experiments were performed in batch reactor and changing effective factors such as pH, time and concentration of carbon nanotubes. Removal efficiency was investigated using a Friedman statistical test, software SPSS-16.The highest removal efficiency was 82.5% at a concentration of 100 mg/L of carbon nanotubes, pH = 10, retention time of 10 min and nickel concentrations of 40 mg/L. The results showed that carbon nanotubes have a high ability to absorb high concentrations of nickel in the aquatic environment.

Organic and mineral compounds generated as products of waste mineralization within biological processes and accompanying physical and chemical processes are washed out by percolating rainwater through the deposit of wastes in landfill and form leachate that has created many health and environmental concerns.This study intended to determine the efficiency of reducing COD, BOD5, TS and color of Hamadan landfill leachate by using carbon nanotubes. Experiments were performed in batch reactor and changing effective factors such as pH, time and concentration of iron nanoparticles. The efficiency of carbon nanotubes were investigated using a statistical test, One-Way ANOVA software SPSS-12. Highest removal efficiency was at concentrations of 2500 mg/ L NZVI, pH = 2.5 and 10 minutes reaction time, 58.23%, 12.5%, 66.87%, 80% for COD, BOD, TS and color, respectively. The project results showed high potential for carbon nanotubes into absorbing organic use for treatment or pretreatment of Hamadan landfill leachate.