EVALUATION OF MARGINAL-QUALITY WATER TREATMENT AND USES BASED ON SOLAR ENERGY TECHNIQUES

Abstract

The present study introduces an application of solar energy in water treatment and desalination for small scale needs. A lab scale solar system is used for brackish and agricultural drainage water (ADW) treatment and desalination. ADW passes through sand filter to solar collector, and then the heated water enters to evaporating chamber maintained at low pressure. Once the hot water enters to this chamber it is evaporated and condensed to fresh water. The effect of the different factors such as solar radiation, vacuum pressure, cooling water flow rate and inlet water temperature on system productivity was studied. An economic analysis was conducted to estimate the cost of water production by the proposed system. The system was efficient to reduce Total Dissolved Solid (TDS) from (1500-2400 mg/lit to less than 15 mg/l) and to reduce the Chemical Oxygen Demand (COD) from (50- 90mg/lit to less than 5 mg/lit).The proposed system gives a reasonable production of fresh water up to 5 lit/m2/day with total cost 0.1 LE/lit. The system achieved gained output ratio (GOR) was about 1.2 and distillation efficiency was about 52%. Key words Marginal quality water - solar energy - flashing process - water desalination