The objectives of this study on the impacts of sludge volume and age on the formation of disinfection byproducts were to:
determine whether settled sludge contributes to disinfection byproduct (DBP)
formation;
determine how water quality affects DBP levels; and,
suggest DBP control strategy for Blacksburg/Christiansburg/VPI (BCVPI) Water
Authority. Experimental approach included sampling sedimentation basins for:
TTHM and HAA5 in sludge
water and overlying water, in
µg/L;
total organic carbon (TOC),
in mg/L;
total chlorine, in mg/L;
water temperature, in ºC;
UV254, cm-1; and,
pH.
Sludge volume calculation included:
sludge depth recorded at
nine points along length of
basin;
plotted in Excel and area
under curve was calculated; and,
area x width of basin. Conclusions included:
when operating under normal conditions, and not
applying ClO2, the "overall" TTHM and HAA5 models
may be used to predict DBP levels formed in the
sedimentation basins;
sludge was not found to contribute to DBP formation and therefore,
basin cleaning is not mandatory;
when treating with ClO2 in summer months, predictive
models suggested that sludge is influential in DBP
formation; and,
sedimentation basins should be cleaned frequently. Includes tables, figures.