Oil derivatives separating efficiency in treatment of water contaminated with diesel oil with bio-components

摘要

Laboratory tests simulating the process of polluting stormwater with fuels and subsequent treating in a separator of oil derivative substances were conducted. Diesel oil (pure diesel oil abbreviated as DERV - diesel-engine road vehicle), diesel oil with bio-components, and pure biofuel - BIO100 were the subject of the tests. Depending on the kind of fuel, the differences in the concentration of oil derivatives in the treated samples were observed. The total reduction in contaminants after 2 min of separation amounted to 91% for BIO100, about 94% for DERV with bio-components, and almost 99% for DERV, however, after 10 s of separation, reduction of DERV was about 90%, whereas, reduction of BIO100 was only 2%. The basic parameters influencing the flotation process were also measured, being the interfacial tension and zeta potential. Depending on the type of fuel, the differences in zeta potential amounted to approximately 26% and differences in interfacial tension reached almost 40%. Such differences may indicate the different susceptibility of oily wastewater to gravity separation. It indicates the necessity for examination of whether the assumptions used for separator design will also be correct in the case of treating stormwater polluted with commercial fuels, including biofuels, available on the market.