WATER AND WASTEWATER
Year:2020 | Volume:31 | Issue:7|Papers Count:14

Heavy metals are a major environmental problem and have become a global problem due to their high toxicity and their ability to accumulate in the body of living organisms. The aim of this study was to investigate the concentrations of heavy metals such as arsenic (As), cadmium (Cd), chromium (Gago-Ferrero et al. ), copper (Cu), silver (Hg), manganese (Mn), nickel (Ni) and zinc (Zn) in samples of water and fish from the Malayer Dam in Hamadan Province, Iran. Samples of water and fish were collected in five steps (in May, June, September, October, February) from 19 locations in Kalan dam route of Malayer, in Hamedan, Iran. Water and fish species including Vimba vimba and Cyprinus carpio species were transferred to the laboratory. Fish samples were digested by 4 ml HNO3 and 1 ml HClO4. The amounts of heavy metals in water and fish were determined using ICP-AES and Duncan's test (0. 05) was used for data analysis with SAS software. Results showed that the mean concentrations of the studied heavy metals were lower than the WHO, FAO, and USEPA guidelines for drinking water. The mean concentrations of Zn and Cr were significantly higher than other heavy metals in water samples. The results also showed that the highest concentrations of heavy metals (except Zn) were observed in spring than other seasons. The mean concentration of the heavy metals for Cyprinus carpio followed the sequence Cr≥ Zn>Ni>Cu>Cd>Hg>As>Mn in first sampling. There were significant correlations between all heavy metals’ accumulation in the Cyprinus carpio fish with heavy metals concentration in water samples. The results showed that the concentration of heavy metals in fish samples was correlated with the concentration of heavy metals in water samples and the accumulation of heavy metals in fish increased with increasing concentrations of heavy metals in water samples. The concentrations of heavy metals studied in fish are lower than those limits in the WHO and FAO guidelines and will not cause any harm in human consumption.

Freshwater limitation as one of the most important challenges of water resources management of the country has caused seawater desalting to be considered a suitable option for utilizing nonconventional water resources in some parts of the country. Due to the lack of a comprehensive understanding of the environmental impacts of desalination plants, this study was carried out to investigate the potential environmental impacts of the Kangan desalination plant. In this study, the Life Cycle Assessment (LCA) method was used. So, after preparing an inventory of materials and energy at all stages of freshwater production in the Kangan desalination plant, impact 2002+ version (2. 15) as impact assessment method and SimaPro9 software were used to investigate environmental impacts of all stages of seawater desalination process on impact categories, including: global warming, reduction of non-renewable energies, ozone layer depletion, aquatic and terrestrial ecotoxicity, etc. Based on the results, most of the environmental impact is related to climate change and reduction of primary resources. So that, 3. 224 Kg carbon dioxide equivalent has been released and reduced 55. 035 MJ in primary sources to produce 1 m3 of desalinated water. Also, electricity supply through desalination cycle stages had the most contribution on all impact categories except ozone layer depletion and eutrophication. Due to the maximum contribution of energy on environmental impacts of seawater desalination process, utilization of renewable energy sources can play an important role in reducing the environmental impacts of these plants.

With the rapid growth of the world's population, water demand is increasing, indicating that the water crisis will become more serious in the future. Therefore, water desalination plays an important role in resolving the water crisis. In this study, polysulfone hollow fiber membranes were fabricated using different concentrations of TiO2 nanoparticles via phase inversion method and then, a thin polyamide layer was formed on the outer surface of membranes. The structure and characteristics of membranes were studied and they were used for desalination in forward osmosis process. The results of forward osmosis process indicated that, the water flux of fabricated membrane without nanoparticles was 15. 5 L. m-2. h-1 that increased about 103% and reached to 31. 4 L. m-2. h-1 by addition of 0. 5 wt. % nanoparticles. By increasing the nanoparticles concentration to 1 wt. % the water flux decreased about 20% comparing the fabricated membrane using 0. 5 wt. % and reached 26. 1 L. m-2. h-1. The reverse solute flux of fabricated membrane without nanoparticles was 6. 3 g. m-2. h-1 that decreased to 3. 7 g. m-2. h-1 by addition of 0. 5 wt. % nanoparticles. By addition of 1 wt. % nanoparticles the reverse solute flux decreased to 3. 1 g. m-2. h-1. In general, it can be concluded that the hollow fiber mixed matrix membrane fabricated using 0. 5 wt. % TiO2 has a suitable structure and properties for use in forward osmosis process for desalination.

Considering the increasing rigor of environmental laws, the removal of carbon and nutrients from wastewater is a key aspect of research, and the simultaneous elimination of carbon and nutrients in a bioreactor has a significant impact on reducing reactor volume and energy consumption. The objective of this study was evaluating the performance of an aerobic sequencing batch reactor (SBR) with granulated sludge removing carbon and nutrient (N & P) from an industrial wastewater. Aerobic granules were obtained in a SBR and in the next step, the experiments were designed by a central composite design (CCD) with five levels of biomass concentration (2000-7000 mg/l) and aeration time (6-24 h). Eight dependent parameters as the process responses were measured and calculated. The results showed that the maximum value of total COD (TCOD) removal was obtained to be 69. 07% at mixed liquor volatile suspended solid (MLVSS) concentration of 5600 mg/L and the highest value of the aeration time (24 h). In addition, the low TN removal (47. 5%) directed the study to reduce the oxygen level from 7 to 3 mg/L. A reduction in dissolved oxygen (DO) in extended aeration mode led to an increase in TN removal and a decrease in TCOD, nbCOD, and BOD removal. Overall, granular sludge showed an acceptable performance in terms of carbon removal, however, intermittent aeration could improve nutrients removal from wastewaters.

Nitrate removal using biological heterotrophic denitrification is one of the most effective and economical processes to remove nitrate from drinking water. In recent studies, carbon sources such as acetic acid, methanol, ethanol, glucose, etc. have been used as a carbon source for heterotrophic bacteria. Inevitable residues of these carbon sources in effluent water and the cost of them are the key challenges for applying these carbon sources in drinking water, in the operational scales. To overcome these challenges, in this research, citric acid produced from sugar beet is used as a harmless, relatively economical and accessible carbon source. Also, to remove the remaining trace amounts of carbon source in denitrified water and disinfection of treated water, ozonation has been used as a dual-purpose process. Pilot studies of this process during the operation of about one year on natural water of one of the wells of North Khorasan province in Iran with the nitrate concentration of 104± 10 ppm ppm as NO 3-showed that in four column bioreactor packed with different media such as natural river gravel, polypropylene plastic (PP), polyethylene plastic (PE) and Pumice aggregates and by carbon to nitrogen ratio (C/N) of about stoichiometric amount and HRT of greater than 4 hours and without any other chemical addition, the nitrate removal rate of greater than 85% can be achieved. In the carbon concentrations, about 1. 5 times the stoichiometric value and the HRT of about 5 to 7 hours, the removal efficiency can be as high as 95%. Ozonation of treated water in 30 to 60 minutes also showed that the ozone has the capability of the complete removal of carbon residuals in effluent of the process from 15-30 ppm as COD to about zero.

This study presents a conceptual model with regard to the fundamental role of economic attitude towards water industry as one of the key aspects of the development of internal marketing in the water and wastewater industry. In this study, Interpretive Structural Analysis (ISM) method was used to collect data, interview, design conceptual model and gather data. The results show that according to the conceptual model presented in this study, the economic attitude towards the water industry with high penetration power is recognized as the most fundamental and influential aspect of the development of internal marketing. According to the linkage analysis method, especially the dimension of economic attitude to water industry, infiltration power-dependency is one of the most important aspects of development of internal marketing. In this respect, drafting of outsourcing regulation to improve the performance of water and wastewater industry is necessary.

Conjunctive use of surface and groundwater has received growing attention since the introduction of sustainable development of water resources. Cyclic storage system is an extension to conjunctive use of surface and groundwater in which the surface water bodies and groundwater aquifer(s) satisfy the prespecified demands in an interactive loop. Cyclical exchange of regulated water between groundwater aquifer and surface reservoir is the key element of a cyclic storage system that differentiates it from the conjunctive use of surface and groundwater systems as usually practiced. In the present study, reliability-based design of the cyclic and non-cyclic storage systems models is formulated as a multi-objective programming and intends to minimize the construction and operation costs and maximize the reliability of water allocation to the agricultural sector. Results show that the performance of cyclic storage system significantly improves by more efficient storing of surface water in a groundwater basin in wet seasons (years) and using it during dry periods. So, in order to fully meet the present demands in cyclic strategy, we had to pay just under 90. 4 billion rials, compared to the noncyclic strategy. It is also shown that, for any given cost, the reliability with cyclic strategy well exceeds that of non-cyclic strategy. In addition, the cyclic design of the system implicitly reduces the probability of flooding downstream significantly rather than the non-cyclic strategy.

Current study seeks to present a narrative of the residents of the suburbs of Sanandaj on the provision of services and urban facilities. This was in contrast to the narratives of the Water and Wastewater Company's experts and statistics, documentation and information were posted on the company's website. The underlying assumption of this study revolves around the fact that suburbs lack adequate facilities and services and have been neglected. To this end, we have used sustainable urban development approaches, urban regeneration and quality of life to explain and change this. With regard to the subject and purpose of the study, we used the institutional ethnographic method by which the researcher seeks to expose the status quo and then provide strategies for changing the status quo. Therefore, data were gathered through theoretical, purposeful sampling with maximum diversity and semi-structured interviews until theoretical saturation with 20 subscribers and 7 experts of Kurdistan Water and Wastewater Company, as well as statistics and relevant documents were collected. The information collected was discussed in terms of concepts, primary and secondary categories. Primary categories were conflicting secondary services, quality of technical management, poor technical management, lack of coordination of events, lack of inter-organizational collaboration, inappropriate network infrastructure, and lack of customer-centricity, uncertainties, and overheads. They were drawn and extracted from these categories; the nuclear category of structural and institutional exclusion and the lack of coordination in the implementation and ambiguities of the bill. The results indicate a lack of sustainable urban development in the marginal areas and consequently a decline in the quality of life. This is reflected in the structural and institutional challenges faced by the suburbs in terms of their utilization of urban facilities. The lack of coordination in the implementation and ambiguities of the water and wastewater company has aggravated the process and caused underdevelopment issues. Therefore, what is needed on the outskirts of Sanandaj is the re-creation of a city that is making changes to the development of water and wastewater network infrastructure, maintaining and protecting the network, and transparency in customer billing and promotion, which is the quantity and quality of service provided in these areas.

Sewage collection, transmission and treatment systems are among the basic infrastructures of any city that should be designed to have the least vulnerability during crises caused by intentional or unintentional disruptions. Therefore, observing the principles of passive defense and safety in the sewage sector to protect and reduce vulnerability with the aim of continuing the necessary services, protection of sewage facilities and equipment, meeting the needs of the people, protecting people's lives (preventing the spread of microbial and chemical contamination), continuing to manage, and managing the people (preventing discontent and creating chaos) and, consequently, stabilizing the country's top management are essential and inevitable. Methods: This paper identifies the risks to the critical infrastructure of the municipal sewer system with a passive defense approach as the first step in assessing the sustainability of urban sewer systems and the overlooked points in the design and construction of collection, transmission and transmission network systems and provides wastewater treatment. The present research method is a descriptive survey and is a type of applied research and distinguishes between risk or actual risk (Danger) and threat or potential hazard (Hazard); it also examines the status of asset parameters, threat and vulnerability in design, and has developed urban sewage systems. Results: The results of the research indicate that the regulations and methods of designing urban sewage systems in Iran are not sufficient to protect and increase the sustainability and resilience of the aforementioned systems and therefore, the solutions of defense knowledge. Passive can be considered a good complement to existing methods of designing and constructing urban sewer systems. The research results also show that these systems have been designed or built in the cities of our country, with the least attention to the principles of passive defense. Conclusion: Based on the findings of this study and the nature of urban sewage systems, 48 types of threats and weaknesses and serious vulnerabilities of urban sewage systems were enumerated.

Dye pollutants from numerous industries, due to the highly toxic and non-biodegradability, pose a great threat to the human health and environment. In this research, a magnetic nanocomposite modified with polyethyleneimin (PEI/MGO) was synthesized and used as an adsorbent for rapid, efficient and economic removal of reactive dye. Performance of PEI/MGO for the adsorption of reactive dye from aqueous solution was studied by adsorption method in a batch system. Surface properties of PEI/MGO adsorbent were identified by an FE-SEM technique. Adsorption of dye onto adsorbent was confirmed on the basis FTIR analysis. The adsorption experimental data were fitted by pseudo-first-order kinetic and pseudo-second-order kinetic models by linear regression analysis. Langmuir and Freundlich models were used to describe the adsorption equilibrium isotherms. The adsorption capacity was inversely correlated with the initial pH solution while it was directly correlated with the contact time, temperature, and initial concentration of dye. The percentage removal of dye using synthesized nanocomposite was more than 90± 3% at pH=3, contact time of 45 min, and temperature of 328 ° C. The adsorption process followed pseudo-second-order kinetic and the Freundlich isotherm models. The maximum adsorption capacity of PEI/MGO was 208. 333 mg/g at 298 ° C. Based on the results of the experiments, the synthesized adsorbent represents a significant potential for removal of reactive dye from aqueous solution.

Wastewaters and agricultural effluents are among the main sources of antibiotics and antibiotic resistant microorganisms. Rivers as the sink for the effluents may distribute this kind of contamination in the environment. This study aimed to investigate the variation of antibiotic resistant bacteria density in Gowharrood River. The water and sediment samples were taken at three points along the river (focused on river course in Rasht city), in autumn 2016 and in winter, spring and summer 2017. The number of heterotrophic and coliform bacteria were counted in the Nutrient agar and Eosine-Methylene Blue agar media containing 100 μ g/mL of cephalexin, gentamicin, doxycyclin, ciprofloxacin, and trimetoprim antibiotics, respectively. pH and EC were also measured in water samples. Data for bacteria number were analyzed by repeated measures of factorial arrangement in a completely randomized design by SAS software package. As the river passes through the city, pH and EC of water increase. The average EC value of river water in spring and summer seasons was more than 2. 5 times its value in autumn and winter seasons. The number of heterotrophic and coliform bacteria in both water body and sediment increased as the river passed throutgh the city. The average density of antibiotic resistant heterotrophic and coliform bacteria in the river water was 3. 74 and 2. 79 (Log CFU/mL) respectively, and the average density of antibiotic resistant heterotrophic and and coliform bacteria in sediment samples was 5. 74 and 5. 37 (Log CFU/g) respectively. Resistance pattern of both heterotrophic and coliform bacteria to antibiotics in both sediment and water samples was as follows: cephalexin> gentamicin> ciprofloxacin> doxycyclin> trimetoprim. Seasonal variation patterns for river water and sediment coliforms and sediment heterotrophic bacteria were as follows: winter>autumn>summer>spring. According to the results of this study, Gowharrood river is contaminated with antibiotic resistant, especially cephalexin resistant, bacteria and if the water of this river is used in aquaculture and irrigation of downstream agriculture fields, the antibiotic resistant bacteria and their antibiotic resistance genes may be spread in the other ecosystems and finally may enter the human food chain.

Urban treated wastewater is a useful resource for allocation to various non-potable reuses because its quantity and quality can be controlled and managed by humans, but it has its limitations. Improper use of these resources without treatment can lead to environmental and health risks and, as a result, can cause social dissatisfaction and sometimes economic problems. This paper examines the risks of limitations associated with the use of treated wastewater. Qualitative information of 26 wastewater treatment plants in the country was collected to create a proper database for risk assessment of using treated wastewater for agricultural and industrial application by taking into account the major factors such as environmental, socio-cultural, economic, and technical. For risks calculation, multiple risks associated with the use of treated wastewater were identified by reviewing various available publications and categorizing them according to the above four risk factors. Hierarchical networks were prepared to calculate the main and the overall risk. Bayesian networks were used to model risk-based structures. Bayesian relationships are causal and helpful in expressing the links of the nodes in a probabilistic way. Research results show that the risk of using treated urban wastewater in agricultural sector is generally higher than its application in industrial use, and hence it will make it more suitable and more acceptable for industrial use under current treatment. Bayesian risk-based agricultural and industrial structures were suitably modeled according to R2, RMSE, and MAPE indicators. The average values of the above indicators for the calibration of Bayesian model using treated wastewater in agricultural and industrial risked-based structure were 0. 993, 0. 202 and 0. 637; 0. 988, 0. 980 and 2. 731, respectively. From this study it can be concluded that Bayesian networks have a modeling capability in assessing the risk associated with the use of treated wastewater in agricultural and industrial sectors. The method presented in this paper can be used by the wastewater treatment plant managers and end users when assessing the potential risk of using treated effluent for agricultural and industrial applications.

Water resources in the armed conflict are facing extensive destruction and pollution. Today, protection of water and water resources has become increasingly important during armed conflict. Water resources can be used as a means of warfare, and are also an important source of sustaining civilian life and survival. The key question is, what are the rules in humanitarian law to protect waters during armed conflict? In short, although there are few rules for protecting waters in armed conflict, there are some rules and documents in international humanitarian law. The most important of these rules are: prohibition of water pollution, prohibition of attack on water facilities, guarantee of drinking water rights of prisoners, prohibition of using water as a destructive weapon, and finally the prohibition of attacks on those water resources, which is necessary for the survival of the civilian population. The main purpose of this paper is that for the first time in Persian literature review and analysis of the rules of international humanitarian law concerning the protection of waters and, for the main audience of governments and international lawyers to develop and provide these rules.

Methylene blue as a cationic dye is ubiquitously found in aquatic systems and its presence in water resources can be hazardous. Therefore, this study aimed to investigate extensively the efficiency of activated carbon prepared from grapevine for removing Methylene Blue from aqueous solutions because of its outstanding properties such as cost-effectiveness, simple synthesis, availability, and applicational. For this purpose, the effect of the main operational parameters such as Methylene Blue initial concentration (500-100 mg/l), adsorbent dosage (0. 25-12. 25 g/l), pH (3-11), and contact time (10-90 min) was optimized through surface response method. The obtained results showed that more than 97. 8% of MB has been removed. The experimental data were fitted to the Freundlich model (R2=0. 99) and the maximum adsorption capacity was 2. 23 mg/g. Also, the adsorption kinetics are well explained by the pseudo-second-order (R2=0. 91). This study shows grape waste can be used as a potential alternative candidate for adsorption of Methylene Blue from aquatic environments.