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Factors affecting the spatial variations of water quality of the Mazandaran coastal ecosystem was determined in summer 2012. For this purpose, water quality parameters (nutrients, temperature, conductivity, salinity, dissolved oxygen, pH, chlorophyll α and turbidity) were evaluated along 4 transects (Amirabad, Babolsar, Noshahr and Ramsar) in the depths of 5, 10, 20 and 50m, using multivariate analysis methods.  Based on the cluster analysis of data, the sampling sites could be classified into 5 distinct groups, including 35-50m water layer of station 50m in all transects, 0-5m layer in station 5m in all transects, Ramsar transect and the majority of surface and bottom layers of 3 transects including Noshahr, Babolsar and Amirabad. Based on discriminant analysis, 86.40% of the sampling sites were correctly classified. Factor analysis explained 87.53% of the total variance, the five principal components of which (viz. temperature, turbidity, nitrate, silica and ammonium) were considered as the most effective parameters on the spatial variation of water quality. This study suggests that the number of sampling locations can be reduced to two transects. Thermocline, transport of nutrients (specially phosphorus and ammonium) from rivers, sea floor, cage culture and the ctenophore, M. leidyi, were the most effective sources on spatial variations of water quality. Moreover, the multivariate statistical methods were found to be useful tools to recognize the spatial variations pattern along the Mazandaran coasts in summer.

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The objective of this study was to classify the Shoosh Aquifer to several zones with different water quality in Khuzestan Province, Iran. In this regard, the performance of classification methods (Discriminant function and Cluster analysis) for the classification of groundwater based on the level of pollution with an emphasis on the problem of over-fitting in training data were considered. An over-fitted model will generally have poor predictiveperformance, as it can exaggerate minor fluctuations in the data. Cluster Analysis(CA) was adopted to spatially explain the similarity of sampling stations with respect to measured parameters. Three methods for variable selection were used including regularized discriminant analysis, principal component analysis and Wilks's lambda method. The best algorithm for variable selection was Wilks'lambda which resulted in reducing the generalization error of the test sample to 0.1 for leave-one-out and 4-fold cross-validation. The second best performed algorithm was regularized discriminant function with 0.167 and 0.133 misclassification error for the two above-mentioned methods, respectively. Principal component analysis did not proved to be a promising algorithm for variable selection in the classification methods.

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The effect of drought indices on hydrostatic variations and qualitative parameters of the Zahedan Plain's aquifer was investigated. For this purpose, 12-year statistics from observational and piezometry wells in the plain, the drought index of percentage normal )PN), standardized precipitation index )SPI(, and 30-year precipitation statistics of Zahedan station were used. Results revealed that the PN index had a greater variety than SPI. The aquifer hydrograph showed a rise of 1.37 m in water level from the year 2002-2003 to 2013-2014. Considering the drought conditions in the plain, this rise in the water level can be attributed to the reduced water extraction from the aquifer, because the water requirement of Zahedan city was supplied from other sources, viz. Chah-nimehs. Also, there was a significant correlation between the parameters of anion, TDS, and Na⁺ with SPI. However, PN index did not have any significant relationship with the quality parameters. There was a significant correlation between water level balance and SPI only at the level of 1%.

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Aims: This research aimed to evaluate the spatial patterns of water quality and its controlling factors in the Mazandaran coastal ecosystem during winter using the multivariate analysis methods.
Materials and methods: Water quality parameters such as nutrients, temperature, conductivity, salinity, DO, pH, chlorophyll-a and turbidity were measured monthly in 16 stations (44 layers) along 4 transects (Amirabad, Babolsar, Noushahr and Ramsar). To evaluate the data, several multivariate statistical methods were used including discriminant function analysis, cluster and factor analysis as well as correlation test.
Findings: Results of cluster analysis showed that the sampling sites (44 layers) were classified into 4 groups. Based on discriminant analysis, 93.20% of the sampling sites correctly classified. Factor analysis extracted 4 principal components that explained 74.05% of the total variance. Based on these analyses, organic phosphorus, organic nitrogen, turbidity, chlorophyll-a and temperature were the most effective parameters on the spatial variation of water quality.
Conclusion: This study suggested that the number of sampling locations could be reduced to 3 transects including Amirabad, Babolsar and west coasts (Noushahr and Ramsar) and 2 stations (one surface layer and one deep layer). Transport of nutrients from land, sea floor and fish cage culture were the most effective factors on spatial patterns of water quality in Mazandaran coasts. Based on the results, multivariate statistical methods are also introduced as one of the useful methods for identifying the spatial pattern of water quality.

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The effects of natural zeolite as a bed medium in increasing lettuce and red tilapia growth as well as improvement of water quality parameters in an aquaponic system were investigated. An experiment with a completely randomized design was run with two treatments in triplicates, 1) an aquaponic system without use of zeolite as a control group and 2) use of a small cotton bag, containing 10 g zeolite as a bed medium for planting a lettuce seedling. In each experimental unit, 42 seedlings of lettuce were introduced. The individual weight of fish and lettuce yield in treatment 2 was significantly higher (P< 0.05) than treatment 1 at the end of experiment. The initial mean individual weight of red tila-pia juveniles was 6.23 ± 0.06 g and increased to 32.50 ± 2.00 and 37.50 ± 2.20 in treat-ments 1 and 2, respectively by the end of experiment. The yield of lettuce was higher in treatment 2 (1507 ± 445.00 g/unit) compared to the control (275 ± 83 g/unit). The concen-tration of total ammonia-N in the water was significantly lower (P< 0.05) in treatment 2 compared to treatment 1 at the end of experiment. The concentration of phosphorous and potassium in the fish rearing tanks was significantly lower (P< 0.05) in treatment 2. These results indicated that the use of zeolite, as a bed medium to plant lettuce seedlings in a re-circulating aquaponic system could increase the growth of lettuce seedlings as well as im-proving water quality parameters.

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Aims: There is a relationship between environmental pollutants, particularly heavy metals, the risk of water pollution, and diseases in numerous areas. This study aimed to assess the water quality by measuring physio-chemical properties and heavy metals contents at two water stations in Basra city, Iraq.
Materials & Methods: The water samples were collected from two main water stations of Al-Baradi’yah and Al-Jubaila. The pH values, turbidity, and TDS of the water samples were measured, and the heavy metals analysis of Cd, Cr, and Cu was done by the direct extraction/air acetylene flame method using a flame atomic absorption spectrometer. The results of the parameters were compared with the safe limits of WHO.
Findings: The turbidity and total TDS for both stations showed a significant difference, whereas the pH values were not, referring to the raw and tap water at both stations being acidic (pH<7). A significant difference was observed between the level of Cr and Cd in the raw and tap water samples within the acceptable levels of WHO. A significant difference was observed in the Cu levels in Al-Bharatiya (p<0.05). Whereas, no significant difference was observed between the chromium level in the water samples of the Al-Jubaila station (p>0.05). The amount of the Pb was shown a slight increase from the acceptable levels in the tap water at Al-Baradi’yah station and the raw and tap water at the Al-Jubaila site. 
Conclusion: A part of the chemical parameters is within the WHO acceptable limits, except water turbidity and Pb levels.

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 Based on the chemical properties of herbicide and carrier water, water hardness might have different impacts on herbicide performance. A study was conducted in the greenhouse to determine the effect of chloride and bicarbonate forms of Mg⁺² and Na⁺ on the performance of clodinafop-propargyl and sulfosulfuron for littleseed canarygrass control. The concentrations of bicarbonate and chloride forms of Mg⁺² and Na⁺ had no significant effect on the ED₅₀ of clodinafop-propargyl. The relative potency of clodinafop-propargyl, in the presence of all mineral salts, was 1.0 or had no significant difference from 1.0. On the contrary, increasing the mineral salts reduced the ED₅₀ of sulfosulfuron significantly, especially in the presence of bicarbonate forms of Mg⁺² and Na⁺. In this regard, the relative potency of sulfosulfuron as affected by 100 to 800 ppm Mg(HCO₃)₂ was about 0.5 to 0.7 times higher than control. This value was increased from 0.5 to 2.2 at 100 to 800 ppm sodium bicarbonate. Hence, the ranking of the mineral salts on improving sulfosulfuron performance was NaHCO₃ > Mg(HCO₃)₂ > MgCl₂ > NaCl. It is suggested that because of the lipophilic nature of clodinafop-propargyl, the presence of mineral salts did not affect the performance of this herbicide. It is concluded that, in determining the effect of water hardness on herbicide performance, in addition to chemical properties of herbicide, type of mineral salt, and its concentration, it is also essential to know the changes in the pH of the carrier water due to the mineral salts.

 

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Aim: The purpose of this research is to formulate a program and design a suitable model for environmental monitoring of water quality in order to reduce the costs of water quality monitoring and evaluation in No.1 Zabol Chahnimeh.
Material & Methods: In this study eight sampling stations were selected in the bed of the reservoir No.1 in order to monitoring and measuring physical, chemical and microbial parameters. Sampling was conducted systematically on a month basis for one year. Then the data were analyzed with the help of multivariate statistical methods such as cluster analysis, Principal Component Analysis (PCA) and factor analysis.
Findings: Using multivariate statistical methods, No. 4, 5, 6 stations were selected as the main stations for sampling and factors of temperature, turbidity, DO, COD, magnesium, sodium, calcium, phosphate, chlorine, nitrite, sodium Absorption Ratio and pH was determined as the main water quality indicators. It was revealed that temperature, DO, nitrate and turbidity parameters should be sampled monthly, but the other parameters could be sampled periodically or even quarterly to model an optimal monitoring of water quality in reservoir No.1 during a year.
Conclusion: In general, the evaluation of the quality status of this valuable water resource by reducing the number of sampling stations, eliminating some unnecessary parameters and reducing the frequency of sampling completely and without defects and at a much lower cost is done for this reason, having the lowest costs and proper timing, management of the main reservoir will be possible considering all effective parameters.
 

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This study aimed to assess the effect of a time gap between adding adjuvant and herbicide to the tank on hard-water antagonism of trifloxysulfuron under greenhouse conditions. Treatments consisted of herbicide dose (0, 0.75, 1.5, 3, 6, and 12 g ha^-1), spray carrier (distilled water ± 600 mg MgCl₂, CaCl₂, and FeCl₃ L^–1), the order of adding adjuvant and herbicide to the spray carrier (herbicide alone, the addition of 20 g ammonium sulfate L^-1 or 300 mg citric acid L^-1 15 min before, at the same time, and 15 min after adding trifloxysulfuron to the spray carrier). The dry matter of velvetleaf was regressed over the doses of trifloxysulfuron to obtain herbicide doses in which 50 and 90% velvetleaf control occur (ED₅₀ and ED₉₀, respectively). The presence of Mg²⁺, Ca²⁺, and Fe³⁺ in the spray carrier increased the ED₅₀ from 2.41 to 5.07, 7.65, and 9.78 g a.i. ha^-1 and the ED₉₀ from 5.88 to 16.56, 28.48, and 28.19 g a.i. ha^-1, respectively, indicating a hard-water antagonism of trifloxysulfuron as Fe³⁺ = Ca²⁺ > Mg²⁺. Generally, the best order was adding adjuvants 15 min before adding trifloxysulfuron to the tank. It could completely overcome the hard-water antagonism of trifloxysulfuron. In contrast, the order of adding adjuvants 15 min after adding trifloxysulfuron to the tank had no significant effect on overcoming the hard-water antagonism of trifloxysulfuron, resulting in additional costs for farmers.

 

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Abstract:
Aims: The Meymeh River is fed by several tributaries, leading to a gradual decrease in its quality. Considering the construction of the Meymeh reservoir for agricultural use, it is necessary to monitor the spatial and temporal changes in water quality and to identify areas where river quality changes.
Methods: Our method was based on the analysis of 420 samples over 12 months (2016–2017) in three seasons (low, moderate, and high flow periods) from 35 measuring stations using Spearman's correlation, multivariate statistical analysis, agglomerative hierarchical clustering, and GIS.
Findings: The results showed that crossing the saline evaporite layers (especially the Gachsaran Formation) causes a gradual decrease in water quality from upstream to downstream. So, EC reaches from 400 to more than 3500 µm. cm^-1 at the confluence of Varazan and Kharvazan tributaries. Besides, the sulfur spring with an average EC of 21590 µm. cm^-1 increases EC 3.5 times. Siyoul tributary penetrates under the ground after passing through two saline zones and reappears at a distance of 150 to 200 m with an EC of 187800 µm. cm^-1. It was also found that about 50% of the salinity of the Meymeh River is caused by the influence of the Ghadah Sulfur Spring and the Siyoul tributary.
Conclusion: This study has highlighted some options for managing the level of salinity in the dam. In most cases, one option on its own may not have the desired effect, and a combination of techniques is likely to bring the best results.

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Microbial quality of potable water is of the most import guidelines of the World Health Organization (WHO). One of the main concerns of water supply and distribution network problems particularly in large cities is microbial growth in the pipelines that are significant non-compliers and repeatedly detect bacteria in finished drinking-water. In Iran, chlorine is mostly used as disinfection agent in conventional chemical treatment process in water treatment plants for supplying safe drinking water. This is done to maintain a residual concentration within a water distribution system for preventing the growth of pathogenic bacteria. Therefore, to meet water quality standards, it is necessary to maintain free chlorine residuals throughout the minimum and maximum levels for various reasons. This study was conducted to examine the relationship between residual chlorine concentration, turbidity and microbial quality of water used for drinking in water distribution system of city of Semnan. Heterotrophic Plate Count (HPC) bacteria was used as an indicator for microbial quality and residual chloride concentration and turbidity were selected as the main parameters for determining correlation. In this research, for the first time Water-Gems as a comprehensive and easy-to-use water distribution modeling application bacteriological software with GIS system was employed as a tool to evaluate the microbial water quality in the network of Semnan city which is known as drawn area with limited water resources. Water-Gems is a multi-platform hydraulic and water quality modeling solution for water distribution systems with advanced interoperability, geospatial model-building, optimization, and asset management tools. For the study, all required information from water supply system such as topographical references, type and diameter of pipelines, pressure head in the system and connections were imported in the software. Then sampling points were selected and 25200 samples were made for turbidity, residual chloride concentration and HPC bacteria. The results indicated that there is high correlation between free chloride residual, turbidity and HPC which means that lower chloride concentration caused the increase in turbidity and HPC number. This information can be used to formulate a bacterial growth control strategy.

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The physico-chemical parameters, nutrient status and heavy metal ions of Huluka and Alaltu Rivers of Ambo, Ethiopia were studied. Temperature, pH, electrical conductivity, CO2 content, total dissolved solids, hardness, dissolved oxygen, Ca2+, Mg2+, Cl-, nitrate, phosphate and sulphate have been determined along with selected heavy metals to assess the various water quality profiles along the rivers due to addition of various waste materials through anthropogenic activities. The majority of the parameters show an increasing trend progressing downstream and the declining quality of the rivers. The downstream samples have shown almost a three times increase in most of the measured physico-chemical parameters but fell within the recommended limits for drinking water except for dissolved oxygen and phosphate. Along the river course, most of the heavy metals fulfill the maximum permissible limit for drinking water according to the international standards except Cd and Mn.

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Quality of coastal water is of great importance in environment and other applications. Therefore, studying the quality of this water is quite vital. Traditional methods of water quality studies are time consuming processes that lead to pixel-based information and also impose a great deal of costs. Using stelllite images and remote sensing can play an important role in enhancing the outcome of these studies. In this research, by field sampling of secchi depth, simultaneous to the satellite pass; an experimental statistic-mathematical model was fitted for the acquired data in the field and the processed images of the IRS-LISS-III sensor. The results indicated good relations between the Secchi depth and the radiance received by the sensor. The fitted model can be used to map Secchi depth in coastal areas.

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Groundwater is of important drinking water resources. The quality of those water resources which are not affected by human activities, is characterized by local geological conditions. The present research was conducted in order to investigate the quality of water resources located in the south of Birjand plain, South Khorasan Province, using mass balance techniques. This research dealt with the quality assessment and the distribution pattern of physico-chemical parameters (anions and cations, pH, EC, TSS, TDS, and TH) in the groundwater resources in the region resulting in indentifying the contamination resources. Also, the origins of anions and cations in the groundwater resources as well as their connection with the geological characteristics of the region were evaluated by employing the mass balance techniques. The water sampling was performed systematically based on the distribution wells over the plain, with regard to the distances, and perpendicular to the topographical lines from the heights toward the lower plains down to the main river, 3 kilometers apart across the plain. In average, one third of whole wells in the study area were selected for sampling. The samples were taken during the end of dry season (October 2010) from 27 wells, 2 Qanats, and 1 spring. The cations (Na +, Ca+2, Mg+2, and K+), anions (HCO- 3 , SO 4 2-     , CO 3 2-     , and Cl-), TSS, TDS, pH, and the total hardness of the water samples were measured in the Water, Soil, and Plant   Laboratory, Kavosh Ab Shargh Khorasan Jonobi Engineering Services Co.   To assess the quality of the water resources in the region, in this research the physicchemical   properties of water samples were compared with ISIRI 1053 to identify the contaminated wells. The hardness of the samples was measured and the water resources types were identified using Piper Diagram. Also, through calculating the correlation factors and mass balance, hydrogeochemistry of water resources and probable origin of cations and anions were assessed. The results showed that 50%, 30%, and 10% of the groundwater resources are contaminated with magnesium, sodium, and chloride respectively. The petrological studies verified the presence of ophiolite sequence. A set of ultramafic rocks and basic magma (spilites) with wide developments in southern heights of Birjand plain which had the most effects on the water quality of the region. The water resources contaminations in the region may be due to the presence of listonites from the alteration of ultramafic rocks existed in highlands, upstream of the groundwater resources. 96% of groundwater resources are classified as very hard water. The types of groundwater vary from carbonated calcic in highlands to chloride sodic in downstream and east of the region due to high solubility of Na + and Cl- existing in the soil. %36.6 of water resources were chloric-sodic and the rest were classified as chloric-magnesic, bicarbonatesodic, and bicarbonate-magnesic. The correlation analysis of the parameters indicated that sodium has a very high correlation with chloride, potassium, and sulfate. The positive correlation of Mg 2+ with Ca2+ (+0.614) is an indication of the same origin for both ions. Also, EC with TH (+0.710) and Ca 2+ (+0.710) and TH with TSS (+0.641) show positive correlation. In general, these positive correlations indicate the common geogenic origin of cations and anions in water resources of the region. WATEVAL software was employed for calculating the mass balance using the concentration of anions and cations to find the effective parameters and origin of ions in the water resources. These calculations verify and emphasize on the influence of geological conditions of the region on hydrogeochemical properties of water resources of the plain. Mass balance analysis denotes that the origin of sodium and potassium could be the ion exchange process originated from weathering of mafic rocks (spilites) while the calcium may be released due to weathering of plagioclases of sub-volcanic mass, ferromagnesian minerals, carbonated listonite, and dissolution of limestone in the region.  

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Water quality assessment provides a scientific basis for water resources development and management. This case study proposes a Factor analysis- Hopfield neural network model (FHNN) based on factor analysis method and Hopfield neural network method. The results showed that the factor analysis (FA) technique was introduced to identify important water quality parameters. Results revealed that biochemical oxygen demand, permanganate index, ammonia nitrogen, nitrogen, Cu, Zn and Pb were the most important parameters in assessing water quality variations of the study area. Considering these parameters, water samples of the sampling sites were classified as follows: six into Class III, eight into Class IV, and six into Class V. Afterwards, a water quality map was based on the results of water quality assessment by Factor analysis-Hopfield neural network model. It showed that the southwestern part of the study area had a generally optimum water quality, while in the northeastern part, the quality was seriously degraded. Factor Analysis-Hopfield Neural Network was much better than the Hopfield Neural Network in effectively reducing the degree of Hopfield neural network over-fitting caused by the inputs, thereby achieving more reasonable results. The comparisons with BPANN, fuzzy assessment method, and the Nemerow index method indicated that the FHNN model provided more reliable judgment and valuable information than the three other water quality classification methods.

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Preservation and optimal usage of water resources are that main aspects of sustainable development in each country. Knowing qualitative and quantitative problems in water resources monitoring systems is one of the most important steps in water resources system management and pollution reduction plan. Recent studies in the field of water quality monitoring network has showen the needs for more researches, despite the abilities and investments in this field. One of the most important problems is the difference between required data and provided data in monitoring networks. So, monitoring systems should be revised and modified in several cases. High monitoring expenses necessitates optimizing monitoring systems to prevent cost loss. Being aware of network properties is an essential step in evaluating existing quality monitoring network. Locations of sampling stations, time frequencies, qualitative variables specifications and sampling duration should be considered in these evaluations. Reduce the cost of monitoring networks and maximize the obtained information, is the common objectives of the monitoring networks planning. From a monitoring perspective, identification of the reservoir eutrophication situation is of particular importance. Eutrophication phenomenon affects water quality strongly and causes serious limitations on the water utilization ability. Autotrophic organisms and algae overgrowth increased turbidity, toxic substances, increased sedimentation rate, oxygen concentration in the middle of the day and reduced severely by decreasing sunlight from sunset until next day morning, which causes anaerobic regions creation in deeper areas of the reservoir as the result. In this study, locations of Karkheh dam reservoir that there was maximum variations in quality indices values using CE-QUAL-W2 model, was identified. PO_4, NO_3, chlorophyll A and dissolved oxygen was studied to eutrophication control in reservoir. Because of limited available data from the time frequencies and sampling location point of view, dam reservoir was modeled by CE-QUAL-W2, 2D qualitative model for a period of one year. Using time series developed in previous step in model cells, time variance of studied parameters in the entire model cells was calculated and was used as a measure of its value change during time. Critical path from monitoring point of view was obtained after fitting best curve to cells with maximum time variance for studied qualitative indices. Placement of monitoring stations on this route will get the maximum information about the quality of the monitoring operation. The results showed that the proposed methodology is efficient in determination of critical paths for quality indices from monitoring perspective, in the dam reservoirs. ...Being aware of network properties is an essential step in evaluating existing quality monitoring network. Locations of sampling stations, time frequencies, qualitative variables specifications and sampling duration should be considered in these evaluations. Reduce the cost of monitoring networks and maximize the obtained information, is the common objectives of the monitoring networks planning. From a monitoring perspective, identification of the reservoir eutrophication situation is of particular importance. Eutrophication phenomenon affects water

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Present study examines whether there is any beneficial effect of magnetized water application on seedling emergence of maize seeds. Water from various sources like tap water, saline water (1,500 ppm), canal water, and sewerage water was treated magnetically by passing it through 235 mT magnetic fields at 3 lpm flow rate. Seeds were soaked in water for 24 hours and planted in sand culture. Number of seedling emerged were counted on daily basis while growth data was measured 15 days after planting. Emergence indicators like Emergence Index (EI), Emergence Rate Index (ERI) and Mean Emergence Time (MET) were used to evaluate the germination of maize seed. Results of the present study revealed that application of magnetized water promoted the germination of maize seeds. Emergence index and emergence rate index values increased from 5.50 to 8.92 and 10.06 to 12.84 and the mean emergence time was reduced 17.90% for magnetized sewerage water in contrast to non-magnetized. Magnetized water treatment showed faster and heavier growth in all water types. Overall, the maximum increase in length and weight of emerged seedlings was noted with magnetized sewerage water. Since the results are based on limited laboratory scale study, further testing of magnetized water application in irrigated environment is suggested before making any concrete recommendations.

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Foam fractionation or foam floatation technology has been introduced to remove fine particles in the Recirculation Aquaculture System (RAS). The main objective of this study was to assess the effect of a dissolved air flotation reactor on foam floatation efficiency in a conventional RAS. In this study, two different types of air bubble producers were tested for 30 days: dissolved air flotation reactor was compared to a commercialized air bubble producer in a skimming column. Nitrogen concentrations and particles removal rates were measured every other day during the study. The results showed that average rates of ammonia and nitrite concentration were lower in the system equipped with air flotation skimmer compared to those in the air bubble system (0.39 and 0.35 versus 3.45 and 0.65 mg L^-1, respectively; P< 0.05). However, nitrate concentration was not influenced by the foam floatation systems (P> 0.05). Nitrogen concentrations were almost similar in the two treatments up to day 15 of the study and then showed higher values for the air bubble system.Total particle collection was significantly higher in the systems containing air flotation skimmer (296.1 versus 276.4; P< 0.05), though daily collected particle was almost similar in both systems at the end of the study. In conclusion, dissolved air flotation skimmer was able to remove a larger portion of particles rendering improvement of water quality in RAS.