advanced separation and anaerobic digestion technologies for value-added bioproducts and biofuel from pulp and paper mill wastes
abstract
in the first research project, the extraction of hemicellulose from the process water and synthetic
hydrolyzate using liquid-liquid extraction (lle) was examined. specifically, the effects of the main
experimental variables (the type of solvent, hydrolyzate to solvent volume ratio, and ph) on extraction
performance were explored. the tested solvents showed varying affinity and selectivity to recover
hemicellulose. it was found that the hemicellulose extraction efficiency of n-hexane (71.03%) and tributyl
phosphate (tbp) (72.34%) was higher than that of 1-butanol (62.36%), and toluene (67.03%) at a solvent:
hydrolyzate volume ratio of 1:3. a ph value of 4.3, a phase ratio of 1:3 ml/ml, and an extraction time of
30 min were considered optimal conditions for hemicellulose extraction.
in the second study, the thermophilic submerged anaerobic membrane bioreactor (thsanmbr) technology
was used for pulp and paper primary sludge treatment, and both biological and membrane performance
were evaluated. the biological performance was studied in terms of biogas production, solids reduction,
chemical and structural changes of the digestate, and permeate quality under various operating conditions.
while the effect of primary sludge on the membrane performance and fouling was systematically
investigated. several experimental parameters were investigated including solids retention time (srt) (32-
55 days), hydraulic retention time (hrt) (3-8 days), organic loading rates (olrs) (2.5-6.8 kg-cod/m3d),
temperature (50±1°c), membrane fouling and cleaning frequency. membrane performance was evaluated
by monitoring its flux and corresponding transmembrane pressure as well as changes in its chemical and
physical properties resulting from operating conditions using fourier transform infrared (ftir), scanning
electron microscopy (sem), energy-dispersive x-ray analyzer (edx), contact angle, and pore size
measurement. [...]