Chlorella vulgaris is a source of protein, vitamins, minerals, essential fatty acids, natural colorants and carbohydrates. This microalga is used as food, health food and food supplement. This study was performed to investigate the possibility of cultivation of chlorella using saline waters in the novel 80 L photobioreactor, designed and constructed by ourselves. This photobioractor has the ability for simultaneous production of biomass and fresh water. At the first step 5 different strains of chlorella was cultivated under 0.5, 6 and 12 g.L^-1 NaCL and the most salt tolerant strain was selected. Afterwards the selected strain was cultivated at above mentioned salt concentrations in a 2 L fermento rtype photohioreactor under 25 °C, pH 6.7, agitation rate of 300 rpm, aeration rate of 4 vvm for 9 days. The light intensity at the first two days was 130 µmoLs^-1.m^-2 and then 230 µmoLs^-1.m^-2. By increasing the salt concentration from 0.5 to 6 and 12 g. L^-1, biomass production was decreased from 2.35 to 2.12 and 1.34 g. L^-1, respectively. Protein content of the biomass however increased from 22.5% to 27.5% and 34.2%, respectively. Total protein production considering the biomass concentration was 0.53, 0.58, and 0.45 g. L^-1. Therefore, the optimum salt concentration for protein production was considered 6 g. L^-1. By increasing the salt concentration chlorophyll content of the biomass was decreased from 18.11 to 15.14 and 7.23 µg.mg^-1, respectively. Ash content of the biomass was also 1.85%, 0.89% and 0.65%. respectively. Fatty acid analysis by GC showed that the salt concentration had no significant effect on fatty acid profile of the biomass. The main fatty acids of the microalga was oleic acid, linoleic acid palmitic acid, and linolenic acid  forming 86% of the total fatty acids. It was concluded that for production of biomass, protein, chlorophyll, ω₃, ω₆, and ω₉ fatty acids by the selected strain, low value salty waters containing up to 6 g. L^.-1 NaCl could be used.                         .
On the basis of these results the strain was cultivated in the the novel 80 L photobioreactorwith a medium containing 3 g. L^-1 NaCI under 25 °C, pH 6.7, aeration rate of 50 L.min^-1, light intensity of 300 µmol.s^-1.m^-2 for 9 days. Comparison of the biomass production in the novel photobioreactor with the 2 L fermentor-type photohioreactor showed a 25% decrease. This decrease, as a result of scale-up, is usual in general for bioreactor and specifically for photobioreactors. The amount of fresh water produced under above mentioned conditions was 1 L.m^-2.d^-1. It can be concluded that the novel photobioreactor could be successfully used for simultaneous production of chlorella and fresh water.