Environmental Engineering Reference
In-Depth Information
CN matrices, and sterile soil systems ranged 16-18%. However, based on the CN
chemistry, the
-CN entrapped matrix is sensitive to cations, the application for site
remediation may not be practical because environmental media (soil, infiltrate, and
groundwater) normally contain several types of ions.
There has been no work on CTA entrapped cell applications for site remediation.
The CTA matrix should be suitable for practical use in site remediation because
it is very durable. However, the toxic chemicals used for the CTA entrapped cell
preparation may cause additional contamination to the environmental media.
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7.4 Conclusions and Future Perspectives
Entrapped cell bioaugmentation is a potential technology for contaminant removal.
It provides better cell retention and tolerance compared to traditional planktonic
cell bioaugmentation leading to higher contaminant removal efficiencies. In the
last decade, studies on the applications of entrapped cell bioaugmentation for
wastewater treatment have been mainly on xenobiotic treatment enhancement. The
drawbacks associated with entrapped cell bioaugmentation, such as effect of entrap-
ment procedure on cell viability, substrate diffusion limitation, and durability of
entrapped cells were discovered and solved. For site remediation, the entrapped cell
bioaugmentation investigations have been on remediating runoff, infiltrate, and soil
contaminated with urban, industrial, or agricultural residues. Previous work exam-
ined the contaminant degradation performance, and augmented cell retention and
tolerance under different environmental stresses.
Entrapped cell bioaugmentation is a technology that has been tested at bench
scales. The technology has been verified under controlled laboratory conditions
for its potential for both wastewater treatment and site remediation applications.
Recent laboratory research efforts have been on testing the technology under dif-
ferent environments such as contaminated soils and agricultural infiltration. In the
future, entrapped cell bioaugmentation will likely move on to pilot and field scales.
Additionally, more environmental applications of the technique may be studied. For
example, the technique can be used for in-situ treatment of landfill leachate and
degradation of organic solid waste (bioaugmented landfill bioreactors).
The uses of entrapped cells for contaminant removal regardless of the scheme
have been in a black-box manner. In-depth investigations on important aspects
of entrapped cells including growth, metabolism, morphology, and genetics com-
pared to those of free cells are needed. These understandings at the cellular and
molecular levels of entrapped cells would enable more accurate prediction of their
behaviors and effective bioaugmentation. Most of the work on entrapped cell
bioaugmentation has been limited to laboratory scales. A lack of low-cost and
industrial-scale production of entrapped cells is a major impediment for practi-
cal applications of the technology. If this issue could be resolved, entrapped cell
bioaugmentation, which is a technically capable process, would turn into a sustain-
able practice and consequently one of the commonly used contaminant removal
technologies.
