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Showing 6 results for Urban Waste
Antibiotic Resistance of Isolated Bacteria from Urban and Hospital Wastewaters in Hamadan City
M Hadi, R Shokoohi, A.m Ebrahimzadeh Namvar, M Karimi, M Solaimany Aminabad,
Volume 4, Issue 1 (5-2011)
Abstract

Background and Objectives: widely use of antibiotics as therapy and uncontrolled discharge of them to receiving waters increased the percentages of antibiotic resistant bacteria in various environments which may cause problems in therapy. The aim of this study was to investigate the antibiotic resistance of E. coli, K. pneumoniae and P. aeruginosa bacteria isolated from urban and hospital wastewaters. Nine antibiotics namely Chloramphenicol, Ciprofloxacin, Trimethoprim Sulfamethoxazol, Gentamycin, Ceftizoxime, Nalidixic Acid, Ceftazidime, Ceftriaxon and Cefalexin were investigated in this study.
Materials and Methods: through a cross-sectional descriptive study the isolation of bacteria from hospital and urban wastewater samples was performed by microbiological identification techniques. The resistance to nine antibiotics was tested by application of the standard disc diffusion technique and zone-size interpretation chart of Kirby-Baeur. Non-parametric Mann-Whitney test was used to assessing two environments differences.
Results: The resistance percentage of E. coli to studied antibiotics was significantly less (ranged from 1.81 to 51.02%) than the resistance percentage of P. aeroginosa (ranged from 3.57 to 61.76) and K. pneumoniae (ranged from 6.45 to 91.83%). the highest resistance to antibiotics studied was for K. pneumonia in comparison with others. E. coli, K. pneumonia and P. aeroginosa bacteria showed the highest resistance to CAZ, SXT and CN, respectively. The study showed the resistance rate in hospital wastewater is more than urban wastewater.
Conclusion: Easy access and uncontrolled usage of antibiotics cause discharge of antibiotics to wastewaters and consequently diminish the drugs' effectiveness. High concentration of antibiotic and diversity in wastewater of hospital in comparison with urban wastewater causes to transfer resistant agents between bacteria and increased the multiple resistances.


Comparison of the Environmental Impacts of Different Municipal Solid Waste Treatments using Life Cycle Assessment (LCA) (Case Study: Tehran)
S Nasrollahi-Sarvaghaji, R Alimardani, M Sharifi, Mr Taghizadeh Yazdi,
Volume 9, Issue 2 (9-2016)
Abstract

Background and Objectives: The continuous increase in solid waste generation worldwide due to population growth and industrialization, calls for management strategies that integrate concerns for environmental sustainability. By quantifying environmental impacts of systems, Life Cycle Assessment (LCA) is a tool which can contribute to answering that call. The aim of this study was to evaluate environmental pollutants resulting from various treatment options including anaerobic digestion, incineration, and landfill of Municipal Solid Waste (MSW) generated daily in Tehran.

Materials and Methods: First, the physical properties of the waste and consumption of inputs in the study area were determined from September to October, 2014- 2015. Then the different steps of LCA in relation to each of the subsystems were followed (with SimaPro software). Finally, the results based on the CML Baseline 2000 were presented and analyzed.

Results: It was found that when the higher rate of separation and processing in any subsystems increases, the emission of environmental pollutants decreases, so that the global warming potential, acidification, eutrophication, and abiotic depletion as the most important impact categories in the subsystems of anaerobic digestion were obtained as -125935 kg CO2/day, -449 kg SO2/day, -1690 kg PO43-/day and -0.43 kg Sb/day, respectively and in incineration were obtained as -264872 kg CO2/day, -974 kg SO2/day, -3471 kg PO43-/day and -0.76 kg Sb/day, respectively, while in the landfill subsystem, they were estimated to be 74478 kg CO2/day, 362 kg SO2/day, 118 kg PO43-/day, and 0.13 kg Sb/day, respectively.

Conclusion: According to the constituent processes of each of the subsystems and the results of the evaluation of exhaust emissions subsystems, it can be concluded that in an integrated system of waste management, the energy-generating systems such as anaerobic digestion and incineration should be as the first priority and the traditional subsystems such as landfill should be as the last priority.


Algal treatment of a mixture of urban wastewater and Vinasse using Spirulina platensis microalgae
M Gholizadeh, M Nosrati,
Volume 12, Issue 3 (12-2019)
Abstract
Background and Objective: Algal wastewater treatment is a new and economic technology to remove and recycle nutrients from wastewater. In order to investigate the effect of vinasse on microalgae growth and also the effect of its growth on nitrogen and phosphate removal in a mixture of urban wastewater and vinasse, the growth of Spirulina platensis was studied.
Materials and Methods: Growth ability of spirulina in the urban wastewater and the effect of vinasse on growth rate was investigated by the calculation of biomass. The effect of concentration of vinasse, intensity of light and light-dark cycle on growth rate were studied by DESIGN EXPERT and CCD method. By selecting the optimized conditions, rates of nitrogen, phosphate and COD removal was investigated at the end of the growth period.
Results: The results showed that adding vinasse to wastewater increased the growth rate and the highest amount of biomass of 3.19 mg/mL was obtained in the sedimentary stream containing 0.25% vinasse. By evaluating the effect of vinasse concentration, intensity of light and light-dark cycle on growth rate, optimal conditions at vinasse concentration 0.4% (v/v), light intensity of 5000 lux and light period of 10 hours, 480 (mg/L) of biomass was obtained. The percentage of removal of nitrogen, phosphate and COD was 63%, 97% and 73% respectively.
Conclusion: The results of this study indicated the capability of urban wastewater and vinasse in order to replace Zarouk's culture medium for growth of Spirulina microalgae. These microalgae were able to remove high percentage of nutrients in the wastewater.
 

Selecting the best options of management of municipal solid waste using life cycle assessment methodology (Case study: Noor city)
Ma Zazouli, Z Karimi, R Rafiee,
Volume 12, Issue 4 (2-2020)
Abstract
Background and Objective:  one of the major challenges in urban management in human societies is related to the collection, recycling and disposal of solid waste and sewage. Poor waste management causes pollution of water, soil and air. It will have a major impact on public health. The aim of present study was to investigate the current status and select the best options of management of municipal solid waste in Noor city (Mazandaran, Iran) using life cycle assessment (LCA) methodology.
Materials and Methods: This research considered with five scenarios: 1) Recycling, composting and unsanitary landfilling; 2) Recycling, composting and sanitary landfilling; 3) Recycling, incineration and sanitary landfilling; 4) Recycling, composting and anaerobic digestion, incineration, sanitary landfilling; 5) Recycling and unsanitary landfilling. The required data for life cycle assessment inventory were collected through reviewing resources, preparing of questionnaires, completing the questionnaire by staff, and field inspections.The life cycle inventory was approved by the IWM model.
Results: The scenario 5, which is the current situation in the region, had the highest environmental impact in terms of toxic emissions and ecological indicators among all the scenarios. Energy consumption in the scenarios 1 and 5 was higher than the unsanitary landfilling in comparison to the other scenarios. Accordingly, the scenarios 5 and 4 had the most and the least impact on methane gas production.
Conclusion: According to the ecological index, the fourth scenario including recycling, composting and anaerobic digestion, and sanitary landfilling was the best scenario.  Fifth scenario with the highest pollution load was the worst scenario evaluated.

Identification and analysis of factors facilitating the green entrepreneurship process in the field of municipal waste
Sahar Rostami, Farhad Darvishi Se Talani,
Volume 13, Issue 3 (11-2020)
Abstract
Background and Objective: Nowadays, the development of green entrepreneurship plays an important role in sustainable employment, reducing environmental issues, economic development, and moving towards sustainable development. Thus, the present study has been carried out aiming to identify and analyze the factors facilitating the green entrepreneurship process in the field of urban waste using a mixed (quantitative-qualitative) method.
Materials and Methods: The present study was carried out with a mixed approach (exploration projects). For this purpose, using theoretical sampling logic, 14 experts were selected by snowball technique and the required data were collected through semi-structured in-depth interviews to achieve theoretical saturation. In the quantitative section, data were collected through interaction questionnaires handed out to 26 experts who were selected through purposive sampling, and the integrated DEMATEL-ISM technique was employed to build a regular hierarchical structure.
Results: Layer-by-layer model was displayed in 4 levels using DEMATEL-ISM technique. The first layer consists of improving laws and regulations and designing a suitable landscape as the most infrastructural, the second layer includes improving infrastructure issues, expanding supportive issues, culturalization and increasing public awareness, the third layer includes exploiting the potentials of the region and attracting private sector participation, and the fourth layer comprises of entrepreneurial management.
Conclusion: The results show that the first step in creating a facilitator environment for green entrepreneurship process in the field of urban waste is to improve the macro structures that should be facilitated mainly by the central government, the second step is related to the proper infrastructure and preparation of public space governing the society. In the third step, it was found that the development and utilization of the region’s potential increases its operational effectiveness. Finally, with entrepreneurial management, all activities that occurred at previous levels can be used effectively.

Effect of irrigation with treated wastewater on lead and cadmium accumulations in soil and sweet pepper plant
Maliha Afkhami, Fazel Amiri, Tayebeh Tabatabaie,
Volume 14, Issue 1 (5-2021)
Abstract
Background and Objective: Limited water resources in arid and semi-arid regions are one of the major limiting factors in agricultural production. Thus, unconventional water resources, such as urban treated wastewater, may be used for irrigation. Application of wastewater to the soil may cause accumulation of heavy metals (HMs). Soil pollution causes uptake of these metals by plants and their entrance to the food chain. In the present greenhouse research, concentration variations of HMs (lead (Pb) and cadmium (Cd)( in soil and sweet pepper (Capsicum annuum) plant were investigated.
Materials and Methods: The experiment was conducted as a completely randomized design with three replications and irrigation with different wastewater treated (well water, wastewater treatment and diluted wastewater). To evaluate the effects of different irrigation treatments on soil, parameters of acidity (pH), electrical conductivity (EC), the concentration of heavy metals Pb and Cd in soil were studied.  Additionally, for the effects of irrigation treatments on sweet pepper plant, parameters of biomass weight, fresh and dry weight and Pb and Cd concentrations (in branches, fruits and roots) were measured. The amount of Pb and Cd in the pepper were measured by ICP-OES. The obtained average concentrations were compared using one-way analysis of variance (ANOVA), and the Duncan test was used to determine the differences between groups (p <0.05). The independent t-test was also used to investigate the difference in concentrations of Pb and Cd in soil and water (p <0.05).
Results: The results of chemical analysis of soil and pepper showed that irrigation with wastewater did not cause a significant increase in the concentration of Pb and Cd in the soil and in the branches, fruits and roots of the pepper. The concentration of Pb and Cd in the soil and in the branches, fruits and roots of the pepper was within the allowable and standard concentration range. The difference in lead and cadmium concentrations in the soil before planting was not significant; however, at the end of the study period, the Pb concentration in pepper was higher than the Cd concentration. The use of wastewater increased the fresh and dry weight of branches, fruits and roots of the pepper.
Conclusion: The results showed that Pb and Cd concentration in roots and aerial parts of pepper plant was not increased significantly as a result of wastewater irrigation (p <0.05). The results of this study are limited to one growing season and by the continued use of municipal wastewater, the concentration of Pb and Cd in the soil and then in the plant may exceed the standard. Especially in the case of Pb, which seems to have shown a slight tendency to increase relative to the primary soil and the pepper. Therefore, the continuation of this study is recommended to evaluate the long-term effects of Bushehr municipal treated wastewater on the concentration of heavy elements in soil and plants, and soil properties. Overall, it should be acknowledged that based on technical recommendations, the use of treated wastewater are not recommended.

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