Nowadays, due to augmentation of population and expansion of cities and the limitation of fresh water sources in the world, existing water resources cannot meet the human needs. Desalination or reduction of salinity of water through biological methods involves the use of plant species, microorganisms, algae or a combination of them, which can be effective in reducing water salinity. The objective of this study was to investigate the desalination of saline waters by using Dunaliella salina algae. For this purpose, the experiments were carried out as factorial based on completely randomized design. The expected tests were conducted in a laboratory controlled condition for humidity, light and temperature (90 days). During this research, the Electrical Conductivity (EC) was measured daily. The results showed that salt absorption in Dunaliella salina algae was significantly different. High salt absorption was observed in Dunaliella salina at a concentration of 130mS.cm-1. Due to the constant humidity, light and temperature, salt removal from saline water was observed in laboratory conditions. The results of this study indicate that significant reduction of chlorine, sodium and bicarbonate levels were observed using Dunaliella salina algae. According to the results of this study, it seems that reducing salt absorption in algae is due to the use of salt in the metabolism and the growth and proliferation of algae. The absorption process in this study showed that the catch of Dunaliella salina has a good ability to remove salt and can be used as an appropriate suggestion for salt removal from saline water.

AbstractSurface water, especially rivers, is the most important sources of water supplies for drinking, agricultural and industry use and livelihoods. Controlling the pollution of BalikhlouChai River as one of the most important sources of water supply in Ardabil province in Iran is very significance and vital. In this research, the pollution zoning by using the Spatial Multi-Criteria Evaluation (SMCE) model in BalikhlouChai River was carried out to evaluate the trend of changes in water index and other important parameters by considering the physicochemical, biological, socio-economic and cultural constraints. First of all six stations were selected in the study zone and the sampling was performed over a 12 months period, and then the average of obtained parameters was compared with the standard values of Department of Environment in Iran. The results showed that fecal coliform in most stations and BOD5 in stations 4 and 5, and Nitrate in the stations 4, 5, and 6 were more than standard. Next, the related factors and criteria with the changes in pollution trend in river was identified, weighted and prioritized by the Analytical Network Process (ANP) model. Then the basic maps were prepared and the information layers were incorporated into the SMCE model. Finally, the zoning map of BalikhlouChai River specified in terms of pollution and river health in two contaminated and safe areas in the study basin. According to the results of this study, 3 zones for the safe and 3 zones for the contaminated areas in the study region of river basin were determined which respectively the numerical values of 1, 0.85 and 0.75 for the safe zones and 0.2 and 0.1 and about zero values for the contaminated zones were calculated. The results of quality and quantity zoning indicate that the northeast regions of the study area, including Ardabil City outlet and the Qarasu River basin have gained almost zero value.

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The aim of this study is to develop forage maize yield-water functions by applying different levels of irrigation and treated municipal wastewater. This research was conducted during May-August (2019 and 2020) in the field of the Marvdasht municipal wastewater treatment plant in a completely randomized