drinking water

Water safety planning is a comprehensive assessment and risk management approach that includes all stages of a drinking water supply chain, from the catchment to the consumer. A Water Safety Plan (WSP) ensures the safety of drinking water through this approach. In this study, risk factors were first identified and evaluated. In this research, the level of risks threatening the water supply sources of Imam Ali rural complex of Mashhad city was determined. A descriptive survey method based on the guide of the water safety program and the FMEA method of information analysis was implemented in which the required information was collected using the interview method, past records, a summary of experts' opinions, questionnaires and field visits. By calculating the RPN risk priority number, it was shown that water pollution due to the inflow of agricultural land effluent with a weight of 48.74 was the highest risk and the inflow of pollutants due to the lack of improvement of the wells with a weight of 19.25 was the lowest risk.

Increasing urbanization and industrialization of cities has led to an increase in pollutants and the production of many toxic elements. One of these pollutants is arsenic, which is known as one of the most toxic and dangerous elements in drinking water. The aim of this study is to investigate the method of minimizing the amount of this toxic substance by coagulation and flocculation in drinking water. In order to determine the optimal conditions for arsenic removal by coagulation and flocculation methods, in the first stage, the optimal pH is determined by Jar test as 6. Then by selecting alum as coagulant, lime as coagulant and the optimal pH, the optimal amount of chemical material is obtained as 7.5 mg/lit. Determining the optimal places in the current situation can be the novelty of this paper. At the end, the residual concentration of arsenic is determined by atomic hydride absorption spectroscopy. According to the concentration of arsenic in the incoming water sample which is equal to 91 micrograms per liter, the Jar test is performed in two stages with alum coagulants. Based on the optimal pH obtained in different concentrations of coagulants and also a constant concentration of coagulants, the arsenic removal efficiency in the best case in alum coagulants reached 88.46%, which is equal to 10 micrograms per liter, which according to the WHO, is an acceptable result. The result of this study indicates that the coagulation and flocculation method with alum coagulant and a constant amount of lime as a coagulant has a high efficiency in arsenic removal.

Providing good quality drinking water is one of the most important concerns of today's societies. Using a proper system for the fair distribution of potable water is very necessary and evidently the type of the system will lead to different amounts of water use per capita. Today, the dispute over good quality water resources in arid regions has escalated, Governments are forced to use separate drinking and sanitation water systems. Understanding the consumption of people in the form of per capita is a prerequisite for the proper design of drinking water distribution networks, the data of which are collected and analyzed in different ways. Quality of groundwater resources in Bajestan region, has led to the plan of separate drinking and sanitation water, with the establishment of government water collection stations since 2014. The purpose of this article is to estimate the per capita drinking consumption by query method by considering 378 samples and random sampling at certain distances from each station. The amount of per capita obtained is estimated at about 3 liters, but its amount has a different distribution in different city districts ranging from 2.5 to 4.5 liters. The highest amount is obtained for the new districts with villa texture and the lowest for the zones with more apartments. The results of the survey of the plan and the problems and consequences of its implementation showed that about 69.03% of people are using the water of these stations for drinking and tea, which is the criterion for determining per capita; The biggest problems of withdrawal stations are the numerous breakdowns of the stations and difficulty harvesting them, which requires the revision of some network operations.

Chlorine has the high oxidation power of natural organic matter in water. Chlorine injection produces disinfection by-products as carcinogens and more dangerous (THMs). We used descriptive and hierarchical analysis to understand the characteristics and dangerous factors affecting human health in the face of DBPs in the drinking water of Tabriz City. This research was done in order to provide key and strategic information to perform managerial and practical measures to reduce the risk of cancer and non-cancer. Monitoring and analysis was done by collecting sufficient samples of this research in the dry and wet seasons of the year, focused on the relative factors of the population density of the region and the topography of the urban fabric for functional and management zoning of drinking water distribution network in Tabriz City; Also, by reading some physical and chemical parameters at the sampling site. Samples were transferred to the laboratory in the shortest possible time and samples were prepared and trihalomethane compounds were measured by gas chromatography and mass spectrometer detector. The results showed that the highest average concentration in the Urban network, belongs to the region where a higher percentage of surface water is supplied, which is chloroform 1.3049 ppb, bromoform 2.0961 ppb, bromodichloromethane 2.7713 ppb and dibromochloromethane 4.1891 ppb, which is still less than the guidelines stated by the National Standard of Iran and USEPA and WHO. The results were divided into several subgroups in terms of dry or wet season, different urban areas, surface water or underground water as a source to evaluate the risk of human health. In addition, we also estimated population health risks by gender and age. In the time division, the health risk from exposure to DBPs in drinking water in the wet season was 7.3% higher than the dry season. The total cancer risk for people living in the area all their life was 7.63E-06. Also, the non-carcinogenic hazard index (HI=3.43E-02<1). It shows that there is no health risk in the present situation. In the age and gender division, the health risk assessment of men exposed to DBPs compared to women was equalized as an adult group. But there were differences between different age subgroups. The risk of developing cancer in children was 52% higher than in adults.

Increasing urbanization and industrialization of cities have led to an increase in pollutants and the production of many toxic elements. One of these pollutants is arsenic, which is known as one of the most toxic and dangerous elements in drinking water. The aim of this study was to investigate the method of minimizing the amount of this toxic substance by coagulation and flocculation in drinking water. In order to determine the optimal conditions for arsenic removal by coagulation and flocculation methods, in the first stage, the optimal pH was determined by Jar experiment, then by selecting ferric chloride as a coagulant and lime as coagulant and also the optimal pH. The optimal amount of chemical is obtained, at the end, the residual concentration of arsenic is determined by atomic hydride absorption spectroscopy. According to the concentration of arsenic in the incoming water sample which is equal to 91 micrograms per liter The jar test was performed in two stages with chloroform coagulants, which according to the optimal pH obtained in different concentrations of coagulants and also a constant concentration of coagulants, the arsenic removal efficiency in the best case in chlorofricter coagulants. It reached 98.3%, which is equal to 1.5 micrograms per liter, which according to the standard of the WHO (2011), 10 micrograms per liter had an acceptable result. The result of this study indicates that the coagulation and flocculation method with chloride-chloride coagulant and a constant amount of lime as a coagulant has high efficiency in arsenic removal.

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 NO3- 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.

The purpose of this study was survey on 2,4-D concentration in Ahvaz drinking water in 2018-2019. A descriptive cross-sectional study was based on 10- month sampling program (from December 2018 to September 2019) in six points of distribution networks were conducted. All measured concentrations were less than the maximum allowable concentrations recommended by the National Standards Organization of Iran (1053) and WHO guidelines. In this study, the total THMs determined in autumn, winter and spring ranged from <0.004-2.98μg/L, 0.02-2.41μg/L and 0.01-0.04μg/L, and in summer less than the LOD, respectively. Different studies have shown that pesticides residue concentration in water samples have a relationship with the amount of pesticides used in an area, physical and chemical refractory properties of pesticides and environmental conditions. Thus, using resistant pollutants such as pesticides will be a serious threat to health of water consumers if they are not properly controlled.

Drinking water of city of Garmsar runs into large pools before being filtered. Recently, due to the ‎growth of algae and their blooms in water surface, following the mortality of many algae, the water ‎became unsavory with bad smell. Deterioration of algae causes the accumulation of a wide variety of ‎organic material which provides a suitable condition for the growth of bacteria, insects, and fungi. To ‎study the algal flora of the pools water samples were collected randomly from different parts and ‎depths of the Garmsar water plan pools, in order to suggest solution for blooming problem. The algae ‎were purified after growing on Cu10 culture media. After two weeks, the species were identified ‎according to‏ ‏valid key of Komárek et al., 2014. Morphologic variation of samples investigated to ‎determine their taxonomic condition in Cu10 culture media. Moreover, morphometric and genetic ‎‎(16S rRNA) data were used to characterize the cyanobacteria strains in liquid suspension cultures and ‎solid media under photoautotrophic conditions. Results demonstrated that the studied strains belong to ‎three divisions of cyanophyta, chlorophyta, and bacillariophyta which includes Anabaena, ‎Synechococcus genera belong to cyanophytae, Ulothrix genus from chlorophyta, and Diatoma from ‎bacillariophyta. ‎Given the presence of microalgae in Garmsar drinking water and‏ ‏their associated risk, the molecular ‎methods are suggested as a reliable and accurate method in addition to morphological analysis in ‎order to identify the types of algae that form into harmful algal bloom.‎

With increasing population, reducing the per capita amount of water resources and increasing the physical, chemical and microbial contamination of water, water crisis is one of the major global problems. The purpose of this study is to examine the use of dual system for rural communities in Ferdows city. The study options include the installation of desalination water with a separate network, the establishment of fixed tanks in the villages and water supply by mobile tankers, alley-to-alley traffic, and the use of mobile tankers or routine methods, the transfer of drinking water through the creation of a dual network in the village And the construction of water harvesting platforms, supply of drinking water by the construction of an industrial sweetener plant and the connection to the village distribution network and Use Freshwater Cards Sales Economically and risky, the study was prioritized. According to the results, the cost of supplying drinking water by Use Freshwater Cards Sales per cubic meter is 8000 Rial, but with a mean risk of 20.33, it has the highest risk among the options. The transfer of drinking water through the creation of a dual network in the village economically, at a cost of 15000 Rial, is the second economic priority, with a mean risk of 6.5% with the lowest risk which can be considered as a priority for integrated water supply, given its economic status.  Due to regional climate change and frequent droughts, creating a dual network is the most effective way to deal with problems.

The main objective of this paper is to determine the cost structure of the companies in charge of water production and distribution and to estimate the marginal cost of production of drinking water in Tehran. For this purpose, the Translog cost function is used to estimate the cost of production, transmission and distribution of water in Tehran Water and Wastewater Company. Analysis framework is based on a seemingly unrelated regression system. Time series data for the period of 1997-2012 has been used in this study. The results indicated that the labor, raw materials and other services inputs are substitute sand labor and capital inputs are complements. Results also showed that product cost elasticity is greater than unit and a diminishing returns to scale exists in Tehran Water and Wastewater Company. Finally, by using the calculated parameters and objective of minimizing the total cost of production, transmission and distribution of drinking water, the optimal production capacity in drinking water is calculated for Tehran. The results showed that, the optimal production capacity in Tehran drinking water is 376.15 MCM per year.

The maintenance of health and quality of drinking water is one of the major priorities in water supply systems. Formation of biofilm in water pipelines, tanks and domestic water purifiers is one of the important concerns in this regard. Viruses, bacteria and protozoa could easily transport with water flow among which, some certain bacteria have the ability to attach to the surfaces and form biofilms. Formation and growth of the biofilm could negatively affect the water flow, quality and health. Biofilm forming bacteria eject compounds which protect them against the damaging factors and through this process biofilm become resistant to degradation. Some of the biofilm creating bacteria also have pathogenic capabilities even in humans, which is crucially important in maintenance of the health of drinking water. Due to the importance of knowing the biofilm forming communities in urban drinking water supply, the present paper investigated the biofilm and its major bacterial agents and removal methods.

The physical, chemical and microbial properties of water are crucial criteria for its drinking suitablity. Unfavorable changes in these parameters may threat consumers’ health. The aim of this study was to give a clear view of physical, chemical and microbial quality of drinking water distribution network in Ahvaz compared to the national and WHO standards. This study was a cross-sectional survey conducted based on 48-week sampling program in Ahwaz water treatment plants No. 1, 2, 3, 4 and 5 as well as in six points in water distribution networks. Water analyses were implemented according to the standard methods. Nine tube of fermentation method was used to determine fecal and total coliform bacteria. The mean values of measured parameters were as follows: electrical conductivity 2282.5 μs/cm, turbidity 2.3 NTU, pH 7.8, alkalinity 144.8, hardness 535.5 mg/L as CaCO3, calcium 137.2, magnesium 46.3, chloride 473.2, sodium 311.2, residual chlorine 1, TDS 1382.7, fluoride 0.53, nitrate 6.7, sulphate 370.2 mg/L, total coliform (0) MPN/100 ml, and fecal coliform (0) MPN/100 ml. Accordingly, the quality of drinking water in Ahvaz was not problematical from the health point of view and except the EC, hardness, sodium, and sulphate, all cited results met the national and WHO standards.

Referring the World health Organization definition, a safe drinking water should not threat the consumer health over the lifetime of consumption. The objective of the present study is to investigate the present guidelines in order to improve the Iran drinking water guidelines. To obtain this, the present drinking water guidelines in Iran (named 1053 and 1011 standards) and some well-known guideline (WHO,US EPA and the European Communities) were studied. The Iran guidelines were compared to the other ones and the different points and values were presented as Tables. It was understood that the present drinking water guidelines of Iran do not cover areas such as the water quality indicators based on their resources and lack some suggestions about in-network monitoring plans. It is recommended that Iran guidelines should be revised in two categories: 1. The primary standard including the pollutants threatening the consumers health and the Secondary standards which should be prepared by the local water authorities.

The main aim of the present study was evaluating the performance of a biological hybrid system comprising anoxic bioreactor and aerobic membrane bioreactor (MBR) with immersed micro-filter membrane for the nitrate removal from drinking water during 34 days of operation. Operational conditions were constant hydraulic retention time equal to 17 h and 36 h for anoxic bioreactor and MBR, respectively, influent nitrate-N concentration of 33.9 mg NO3-N/L, and C/N ratio equal to 2. The results demonstrated that nitrate removal efficiency in anoxic bioreactor was in the range of 73-97%. The effluent nitrite-N concentration from the hybrid system was in the range of 0.01-0.02 mg NO2-N/L. Both nitrate and nitrite concentrations in the effluent of system were always below the the World Health Organization (WHO) limit. The effluent chemical oxygen demand (COD) of the hybrid system was always less than 15 mg/L and COD removal efficiency of the system was 92.8±0.1 %. The effluent turbidity was also less than 2 NTU that represented membrane efficacy in preventing microbial mixture washout. The results of this research show that hybrid biological system of anoxic bioreactor-MBR has a very good potential for removing nitrate from drinking water.

Enforcement of policies related to water consumption management necessitates the evaluation of a variety of strategies leading to increased water productivity. One of these strategies is the separation of drinking water distribution from other uses. In this regard, the per capita of drinking water consumption plays a major role in the design of systems for drinking water supply and distribution. However, it seems that few studies have been conducted on the estimation of this amount in Iran. Therefore, the numbers and statistics cited in the references and technical reports are either dependent on standards (IRI MPORG Publication No. 3-117) or extracted from other studies in similar countries in terms of climate and culture. The present study aimed to estimate the per capita consumption of drinking water in Ardakan, Yazd Province, through field studies and a survey of subscribers who collect their required drinking water from public water distributors. For this purpose, the research background at the international level was reviewed and then a statistical methodology was developed and implemented for the survey and field studies. Finally, the data were statistically analyzed and the per capita consumption of drinking water in this area was determined.

A growing interest has been recently shown to the application of modern technologies, especially nanotechnologies, as a management approach to alleviating the adverse effects of environmental pollutants. One area that may most benefit from these new technologies is the water resources management. The present study was designed to evaluate the effectiveness of nanocoagulants in reducing the microbial load of drinking water. For the purposes of this study, the drinking water supply of the City of Ilam was chosen for a case study and its parameters of biological oxygen demand (BOD), total hardness (TH), and fecal coliforms were determined. It was found that application of nanocoagulants at temperatures as high as 40 oC, over a detention time of more than one hour, and at pH = 6 yielded the highest efficiency in removing the microbial load and BOD5, but it had no effect on TH removal. Based on the results obtained, it may be claimed that nanocoagulants may serve as a good alternative to common coagulants and disinfectants in treating drinking water while they can also improve and optimize water treatment processes.

Given the importance of the microbial quality of drinking water and the fact that no comprehensive, analytical study of the microbial quality of drinking water in the Takab rural areas has been reported, this descriptive case study was conducted in the summer and fall 2012 to investigate the microbial quality of drinking water in the study area. The microbial parameters studied included total coliform (TC) and E. coli using the 9-tube fermentation technique and HPC. It was found that the drinking water sampled from 50% of the rural areas not served by the water supply network exhibited coliform and E.coli coliform contaminations while 11.9% of the samples collected from areas served by the water supply network showed coliform contamination and 9.5% exhibited E.coli contamination. The rural populations with access to clean, coliform-free water in areas both served and not served by the public water supply network were 88.4% and 27.5%, respectively, and 85% of the population in all the villages investigated had access to such clean water. Those having access to drinking water free from E.coli were 96.4%, 27.5%, and 91%, respectively, in the three groups mentioned above. Based on HPC test results from these areas, revealed that HPC≥500 in all cases was zero. The latest WHO guidelines recognized 90% E.coli-free drinking water as excellent for communities with populations less than 5,000 provided sufficient samples are taken. Based on the results obtained from this study, the microbial quality of the drinking water in rural areas in TAKAB is desirable but lower than the Iranian standard.

Condensation Irrigation (CI) is a combination of simultaneous desalination and irrigation/drinking water production. As saline water evaporates in a solar distiller and the hot and humid air is transferred into an underground pipeline, fresh water will condense on the inner pipe surface due to cooling of air by the ground. The water thus condensed infiltrates into the soil through pores in the perforated drainage pipes laid in the ground to transfer the humidified air. In this study, the CI system was developed using common buried pipes to determine the amount of water produced. In this setup, condensed water is collected at the end of the pipe to be used for drinking. Observations and calculations indicated a mean water production capacity of 4 liters every 8 hours along a pipe 25m long. Less water was produced on the first day because some of the water was lost to the wetting of the internal pipe walls. Finally, examination of temperature effects revealed that water production along the pipe reduces as we move farther away from the inlet part of the pipe.