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Lookup NU author(s): Professor Thomas CurtisORCiD
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The penetration of light into waste stabilization ponds was studied because of its importance in pathogen removal and algal productivity. The attenuation of light in ponds was dominated by light absorption by gilvin (also called dissolved yellow matter or humic substances) and algae, light scattering processes (turbidity) being of no importance. Gilvin exerts a strong influence over the spectral variation and longer wavelengths penetrate much better than short wavelengths. Estimates of attenuation coefficients in the u.v. suggest that these wavelengths are less penetrating than previously reported. Differences in algal concentrations cause the differences in light attenuation seen between ponds, though they also cause some spectral variation because short wavelengths are more affected by changes in algal biomass than long ones. In the absence of algae there appears to be a lower limit to the clarity of ponds dictated by gilvin and other substances. Secchi disks were found to be reliable instruments for measuring light penetration.
Author(s): Curtis TP, Mara DD, Dixo NGH, Silva SA
Publication type: Article
Publication status: Published
Journal: Water Research
ISSN (print): 0043-1354
ISSN (electronic): 1879-2448
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