Fog water harvesting: Quality of fog water collected for domestic and agricultural use

Each summer between June and September, the Dhofar region in the Sultanate of Oman is subjected to a high incidence of fog. Generally, fog occurs on 20 to 25% of days during the year. This study was to investigate the fog water potential of the area. Field measurements began in July and continued into mid-September 2005 when the fog, although less frequent, was still present. Experiments were conducted using three fog collectors with different local materials: AC filter, green shade filter, and aluminium filter. The results indicated that the total fog water collected during the experimental period of 76 days by AC filter, green shade mesh, and aluminium shade mesh was 995.04, 879.93, and 752.58 L/m², respectively. The ion concentrations at the Dhofar site were studied and found to meet World Health Organization drinking water standards. Water from the three fog collectors was found to be of good quality. Since fog water collection rates are dependent upon meteorological variables, the impact of the various meteorological parameters on collection rates was also investigated in this paper. The results indicated a significant linear association between the collected fog water and the wind speed and rainfall. It was found that fog water collection rates increased with increasing wind speed and rainfall, but this relationship was not seen with temperature, relative humidity, or pressure. More studies are needed to address and clarify the question of bacterial concentrations and heavy metals in the collected fog water.