Biodegradation Of Phenol And 4-Chlorophenol Mixture And Bioregeneration Of Binary Loaded Granular Activated Carbon By Different Types Of Acclimated Biomass
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Date
2017-08
Authors
Voon, Sui Yien
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Industrial effluents mostly consist of mixture of multiple substrates and the
complex interactions between these substrates could affect the performance of
microbial community in both biodegradation and bioregeneration. Acclimating
microorganism to the substrates could reduce the toxicity effect. However, acclimation
to multiple substrates is a time-consuming process. Therefore, the objectives of this
study were (i) to investigate the feasibility of different types of acclimated biomass in
the biodegradation of binary phenol and 4-chlorophenol (4-CP) solution and the
bioregeneration of binary loaded granular activated carbon (GAC), and (ii) to verify
the possibility of replacing binary-acclimated biomass with different types of biomass
which was acclimated to single substrate in biodegradation and bioregeneration. The
biodegradation study revealed that phenol-acclimated biomass (PhAB) was able to
biodegrade both phenol and 4-CP completely but did not fully mineralizing the
phenolic compounds. On the other hand, the binary-acclimated biomass (BAB), 4-CPacclimated
biomass (4CPAB) and the mixture of phenol- and 4-CP-acclimated
biomass (MAB) proceeded to complete utilization and mineralization of both
pollutants with BAB performing better than the other types of biomass. The increase
in initial concentration of phenol to 4-CP (mg/L) from 100:100 to 300:300 decreased
the phenol removal efficiencies and increased the time taken for complete removal of
the phenolic compounds. The increase in biomass concentration from 300 to 500 mg/L
increased the phenol removal efficiencies and shorten the complete substrates removal
time. The time courses of the respective phenol and 4-CP residual concentrations at
their various initial concentrations and 300 mg/L of biomass were obtained. It was
observed that the efficiency of removing the substrates from the bulk solution
decreased with the increase of initial substrates concentration. At higher concentration
ratio of phenol and 4-CP (400:400) all biomass attained 100 % removal efficiency for
either phenol or 4-CP. Despite achieving the highest total removal efficiency and
shortest complete substrates removal time, the bioregeneration efficiency for BAB at
any given concentration were the lowest ranging only from 42 ± 6 to 63 ± 6 %. The
bioregeneration efficiencies of 4CPAB and the MAB were comparable to each other
which were in the range of 52 ± 5 to 70 ± 2 %. The low bioregeneration efficiency of
BAB was due to the higher fraction of irreversibly adsorbed 4-CP caused by longer
contact time between 4-CP and GAC surface. In addition, the formation of biofilm on
the surface of GAC obstructed the GAC pores and reduced the adsorption capacity of
the regenerated GAC. Overall, MAB could be an alternative for BAB when the
concentrations of the substrates were below its acclimation concentration in
biodegradation and bioregeneration of phenol and 4-CP mixture.
Description
Keywords
Feasibility of different types of acclimated biomass in , the biodegradation of binary phenol and 4-chlorophenol