Se. Woodard et Rf. Wukasch, A HYDROLYSIS THICKENING FILTRATION PROCESS FOR THE TREATMENT OF WASTEACTIVATED-SLUDGE, Water science and technology, 30(3), 1994, pp. 29-38
Citations number
26
Categorie Soggetti
Water Resources","Environmental Sciences","Engineering, Civil
A process has been developed for reducing both the mass and volume of
waste activated sludge generated by the biological treatment of a phar
maceutical wastewater, As a result of the mixture rule the sludge is c
lassified as a hazardous waste. Thus, treatment and disposal have trad
itionally been very costly. This study focused on optimizing an engine
ered hydrolysis operation in terms of solids reduction, environmental
impact, practicality and cost. Dewaterability screening studies were a
lso conducted in an attempt to transform the residual solids into a re
adily filterable material. The resultant hydrolysis/thickening/filtrat
ion process begins with room temperature sludge acidification using su
lfuric acid. This results in 50 to 60 percent solubilization of suspen
ded solids, thus sharply reducing the mass of solids to be handled. Al
so, carbon dioxide is liberated during the reaction phase, enabling so
lids separation and thickening to occur via flotation. Subnatant hydro
lysate can then be recycled to enhance solids solubilization. Once pro
perly conditioned with acid and cationic polymer, the residual solids
are readily pressure filtered to cake dryness in excess of 50% solids.
Results of laboratory studies indicate that the overall process is ca
pable of substantially reducing sludge cake production.