Factors affecting the volatilization of volatile organic compounds from wastewater
Charun Bunyakan, Seansuk Seaoung, Junya Intamanee, and Juntima Chungsiriporn
pp. 1083 - 1093
Abstract
This study aimed to understand the influence of the wind speed (U10cm), water depth (h) and suspended solids (SS) on mass transfer coefficient (KOLa) of volatile organic compounds (VOCs) volatilized from wastewater. The novelty of this work is not the method used to determine KOLa but rather the use of actual wastewater instead of pure water as previously reported. The influence of U10cm, h, and SS on KOLa was performed using a volatilization tank with the volume of 100-350 L. Methyl Ethyl Ketone (MEK) was selected as a representative of VOCs investigated here in.
The results revealed that the relationship between KOLa and the wind speeds falls into two regimes with a break at the wind speed of 2.4 m/s. At U10cm ≤ 2.4 m/s, KOLa was slightly increased linearly with increasing U10cm. For U10cm >2.4 m/s, KOLa increased more rapidly. The relationship between KOLa and U10cm
was also linear but has a distinctly higher slope. For the KOLa dependency on water depth, the KOLa decreased significantly with increasing water depth up to a certain water depth after that the increase in water depth had small effect on KOLa. The suspended solids in wastewater also played an important role on KOLa. Increased
SS resulted in a significant reduction of KOLa over the investigated range of SS. Finally, the comparison between KOLa obtained from wastewater and that of pure water revealed that KOLa from wastewater were much lower than that of pure water which was pronounced at high wind speed and at small water depth.
This was due the presence of organic mass in wastewater which provided a barrier to mass transfer and reduced the degree of turbulence in the water body resulting in low volatilization rate and thus KOLa. From these results, the mass transfer model for predicting VOCs emission from wastewater should be developed
based on the volatilization of VOCs from wastewater rather than that from pure water.
