Degree Granting Department
Civil and Environmental Engineering
Robert P. Carnahan, Ph.D.
Marilyn Barger, Ph.D.
Daniel H. Yeh, Ph.D.
lime softening, membrane water treatment, carbonated soft drinks, alkalinity reduction, immersed membrane
Lime softening, chlorination, clarification and filtration have been long recognized
treatment processes for beverage water specifically the carbonated soft drink (CSD) because
it provides consistent water quality required for bottling plants, however these processes are
becoming uneconomical and causes more problems than the benefits they offer. These
processes require very large foot print, occupy large plant volume, and generate large
volume of sludge which causes disposal problems. Chlorination produces trihalomethanes
(THMs) and other by-products which are detrimental to health and imparts tastes to the final
products. Using the newly developed submerged spiral wound ultrafiltration membranes in
conjunction with lime softening may replace the conventional lime softening, clarification
and filtration processes.
This research was conducted to demonstrate the feasibility of integrating immersed
ultrafiltration (UF) membrane with lime softening. The objectives of this research was to
achieve the water quality required by the CSD bottlers; determine the relationships of
operating parameters such as pH and membrane flux with trans-membrane pressure (TMP),
and membrane permeability; determine the optimum dosage of lime; evaluate the operating
parameters as basis for the design and construction of the full scale plant; and predict the
membrane cleaning intervals.
A pilot unit consisting of lime reactor and UF system was designed and built for this
research. The pilot unit was operated at various pH ranging from 7.3 to 11.2 and at
membrane flux rates of 15, 30 and 45 gfd. The pilot unit was also operated at the CSD
bottler’s operating conditions which is pH 9.8 at flux of 30 gfd. The pilot unit operated for a
total of 1800 hours. The raw water source was from city water supply.
The filtrate from the pilot unit achieved alkalinity reduction to 20 to 30 mg/L
preferred by CSD bottlers, with lime dosage close to the calculated value. The filtrate
turbidity during the test was consistently within 0.4 to 0.5 NTU. The TMP values obtained
during the test ranges from 0.1 to 2.5 psi, while the permeability values ranges from 18.19 to
29.6 gfd/psi. The increase in flux results to corresponding increase in TMP, and increase in
operating pH, increases the rate of TMP. Permeability decreases with increasing operating
pH. The TOC reduction ranges from 2.6 % to 15.8% with increasing operating pH. No
scaling of the UF membranes was observed during the test. Thirty days UF membrane
cleaning interval was predicted. The results from this research can use as the basis of
designing and operating a full scale Lime Softening UF Treatment Plant.
Scholar Commons Citation
Aguinaldo, Jorge T., "Precipitative Softening and Ultrafiltration Treatment of Beverage Water" (2006). Graduate Theses and Dissertations.