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Factors Influencing Ultraviolet Disinfection Performance Part I: Light Penetration to Wastewater Particles
Author(s) -
Loge Frank J.,
Emerick Robert W.,
Thompson Donald E.,
Nelson Douglas C.,
Darby Jeannie L.
Publication year - 1999
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143097x122176
Subject(s) - absorbance , ultraviolet , ultraviolet light , wastewater , light scattering , materials science , wavelength , particle size , particle (ecology) , penetration (warfare) , suspended solids , porosity , chemistry , analytical chemistry (journal) , scattering , optics , chromatography , optoelectronics , environmental engineering , composite material , environmental science , physics , engineering , oceanography , operations research , geology
A technique is described for measuring UV absorbance and internal scattering characteristics of wastewater solids. Wastewater solids developed as part of trickling filter and activated‐sludge processes were observed to be strictly absorbing, with light attenuation following the Beer–Lambert law. Absorbance of solids ranged from 3300 to 569 000 cm −1 Although absorbance was found to vary with treatment process type, even the lowest measured value is sufficient to block transmission of UV light to solid material. It is unlikely that wastewater treatment processes can be tailored to allow light transmission to solid material. Extremely high absorbance observed indicates that UV light can only penetrate particles because of high particle porosity, not by transmission through solid material. Also, regions exist within some particles that completely block applied UV light. Longer wavelength UV light was not observed to penetrate particles better than lower wavelength UV light.