Abstract:
The experiments were carried out by using the combined system between
chemical and biological processes for treating the wastewater from alcohol factories
(molasses wastewater) .Two types of molasses wastewater were used in this study, were
stillage and molasses wastewater from anaerobic pond of wastewater treatment plant
(APW). The molasses wastewater samples were collected from Sangsom alcohol distillery
factory, Sampran, Nakhonpatom and Thai Alcohol, Bang-len, Nakhonpatom.
The results showed that when the stillage of Sangsom Alcohol distillery factory
were treated with FeC~, Alum and CaO , the color removal efficiencies were 90.0%,
89.0% and 93.0% respectively. On the other hand ,when the APW were treated with
FeC~ ,Alum and CaO, the color removal efficiencies were 98.7%, 97.5% and 93.6%
respectively. From all the results aboved , we could conclude that CaO and FeC~ were
suitable for removing color substances from stillage and APW, respectively.
For improving of color removal efficiency, the wastewater was aerated and
added with sludge before chemical treatment process, the results showed that when the
wastewater was aerated with sludge, the color intensity of the waste water was decreased.
For example, the color intensity and COD in stillage and APW were reduced about 45.2%
and 73.6% ,9.8% and 94.2% , respectively.
By the Gel Filtration Chromatography, the stillage after aerated with sludge for
96 hrs , some large molecular weight of color substances were adsorbed by sludge. But in
the case ofAPW, the small molecular weight of color substances were adsorbed by sludge.
It might be the nutrients and physical condition in the APW was not suitable for sludge to
remove the color substances. However, the COD of both wastewater could be adsorbed by
sludge.
The stillage and APW samples after aerated with the sludge for 96 hrs were
treated with CaO and FeCI3 respectively, the color removal efficiency were 97.3% and
96.6%, respectively. It might be the effects of sludge for improving the color removal
efficiencies in the chemical treatment step such as changing of structure or size of
molecule of color substance in molasses wastewater.