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Lime‐Soda Sludge Recirculation Experiments at Vandenberg Air Force Base
Author(s) -
Lawrance Charles H.
Publication year - 1963
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.1002/j.1551-8833.1963.tb01011.x
Subject(s) - lime , alkalinity , environmental science , pulp and paper industry , environmental engineering , waste management , chemistry , metallurgy , materials science , engineering , organic chemistry
This article discusses a study that used jar test and plant scale experiments to determine the feasibility and the desirability of sludge recirculation in order to improve overall softening efficiency at the cold lime‐soda water treatment plant at California's Vandenberg Air Force Base. The jar tests indicated that sludge recirculation would further reduce hardness by 20 per cent, provided that suspended sludge was maintained at 0.6 per cent, and that even greater benefits would be realized for higher concentrations up to 5 or 6 per cent. The plant scale experiments could only achieve a suspended‐solids concentration averaging 0.486 per cent in the flocculator suspension because of equipment limitations, but this sufficed to reduce hardness 20.6 per cent below that experienced without sludge recirculation under otherwise identical conditions. Additional benefits experienced were lower phenolphthalein alkalinity and lower Langelier saturation index. Sludge recirculation showed a higher chemical efficiency in the utilization of lime and soda ash than did plant scale treatment without the recirculation.