tailieunhanh - Aesthetic Groundwater Quality Impacts from a Continuous Pilot-Scale Release of an Ethanol Blend

Or consider what our great grandfathers thought about the mountains, which we now consider so scenic. 4 They were 'monstrous excrescences of nature'. 5 God originally made the world a smooth sphere happily habitable for the original humans; but, alas, humans sinned, and the earth was warped in punishment. Thomas Burnet is repelled by these 'ruines of a broken World', 'wild, vast and indigested heaps of Stones and Earth' that resulted when 'con- fusion came into Nature'. 6 John Donne called them 'warts, and pock-holes in the face of th'earth'. 7 Now we know better. After geology, we are more likely to approach mountains, as. | Ground. Water n n _1 _ Monitonng Remeaiation Aesthetic Groundwater Quality Impacts from a Continuous Pilot-Scale Release of an Ethanol Blend by Jie Ma Zongming Xiu Amy L. Monier Irina Mamonkina Yi Zhang Yongzhi He Brent P. Stafford William G. Rixey and Pedro . Alvarez Abstract A pilot-scale aquifer system 8 m3 continuous-flow tank packed with fine grain sand was used to evaluate groundwater quality impacts from a continuous release of 10 v v ethanol solution in water mixed with benzene and toluene 50 mg L each . The geochemical footprint methane CH4 volatile fatty acids VFAs pH oxidation reduction potential ORP dissolved oxygen DO and temperature was monitored more than 11 months. A rapid depletion of DO from to less than mg L and a decrease of ORP from 110 to -310 mV were observed within 25 d of the release. The high-biochemical oxygen demand exerted by ethanol resulted in strongly anaerobic conditions indicated by the accumulation of CH4 up to mg L and VFAs up to 226 mg L acetic acid and 280 mg L n-butyric acid . Measurements at the sand surface 40 cm from the water table using a portable combustible gas detector did not detect CH4. However accumulation of VFAs particularly n-butyric acid during the summer exceeded the secondary maximum contaminant level value for odor odor levels extrapolated from aqueous concentrations which represents a previously unreported aesthetic impact. Temperature variations to C significantly affected microbial activities and a strong correlation was observed between groundwater temperature and CH4 VFAs generation p less than . Overall these results suggest that seasonal variation of odor generation and CH4 concentration should be considered at sites contaminated with fuel ethanol blends. Introduction Ethanol is increasingly being used as a blending agent for gasoline which increases the likelihood of ethanol blend releases during transportation and from underground storage. Thus it is important to .