Odor control in evaporation ponds treating olive mill wastewater through the use of Ca(OH)2.

Different amounts of Ca(OH)2 were added in 2 L beakers containing 1 L of olive mill wastewater (OMW). The mixture was stirred for 45 min and left to settle. Wastewater analysis was used in order to determine the effect of the different amounts of calcium hydroxide in the treating process, three days after the application. The Odor Detection Threshold was used for determining the effect of the treatment in the odors produced in the beakers, three and 30 days after. Both sets of measurements indicated an important reduction in wastewater pollutants and odor emission when 10 g/L of Ca(OH)2 were added. In order to evaluate these results in more realistic conditions. 10 L plastic containers were filled with 6 L of OMW, relevant amounts of Ca(OH)2 were added, the mixture was stirred manually and left to settle in the open. Again, 10 g/L of calcium hydroxide produced the best results in odor reduction and wastewater treatment.

Plant species in a two-year-old free water surface constructed wetland treating domestic wastewater in the island of Crete.

A free water surface wetland treating domestic wastewater for the village of Pompia in Southern Crete was constructed in early 1999 and became operational on September 1st of the same year. The total surface area of the wetland was 5700m2, designed for 1200 people equivalent. Arundo donax (giant reed) was used for the vegetation of the bed. Approximately 4-6 plants were introduced per square meter. Two years later the wetland was well covered with plants. The Arundo donax was developed as the dominant specie covering more than 95% of the wetland's surface, reaching its maximum developing potential in both density (70-90 plants per m2) and size (5-7 m). More than 30 other plants were identified most of them in the banks of the wetland.