Nawaphorn Khumsiri. Removal of humic and fulvic acids from soil by using fenton and microbiological techniques. Master's Degree(Environmental Engineering). Mahidol University. Mahidol University Library and Knowledge Center. : Mahidol University, 2009.
Removal of humic and fulvic acids from soil by using fenton and microbiological techniques
Abstract:
In this study, the degradation of humic acid (HA) and fulvic acid (FA) in
soil samples was carried out by Fenton and microbiological techniques. For the Fenton
Technique, the ratio of HA to H2O2 at 1:560 and of the H2O2 to Fe2+ at 5:1 showed the
maximum removal of extracted HA solution at pH 3. Thus, the optimal ratio of
HA:H2O2:Fe2+ for extracted HA solution removal appeared to be 1:560:112
(0.000714:0.4:0.08 mM). However, the highest HA and FA removal per one gram soil
were 30% and 20%, respectively when humic acid to reagents (H2O2 and Fe2+) ratio
was 1:11200:2240 (25μg:0.8mM:0.16mM) at 3 h contact time. For the microbiological
technique, the two microorganisms; Pseudomonas fluorescens (P. fluorescens) and
Lactococcus lactis (L. lactis) were investigated for degradation of HA and FA from
soil. The efficiency of microbiological technique was evaluated in terms of single pure
cultures, and the mixed culture of two microorganisms at the ratio of 1:1. The batch
experiments were carried out to compare the treatment efficiency for autoclaved and
non-autoclaved soil samples for 50 days incubation period. The highest HA removal
was observed when L. lactis was used as a single culture, with 28% removal for
autoclaved and 21% removal for non-autoclaved soil samples within 20 days.
Similarly, the highest FA removal was also observed when L. lactis was used as a
single culture, with 17% removal for autoclaved and 33% removal for non-autoclaved
soil samples within the same period