PRODUCTION AND HANDLING OF DEHALOCOCCOIDES BIOAUGMENTATION CULTURES - Bioaugmentation for Groundwater Remediation - page 112

are to be mixed directly into electron donor solutions, the compatibility of the compounds and
cultures should be evaluated.
3.8 SUMMARY
Large-scale production of Dhc -containing cultures for in situ bioaugmentation of chlori-
nated ethene contaminated aquifers can be performed economically and result in reproducible
high specific activity and high cell density cultures. Successful large-scale inoculum production
depends on the electron donor (i.e., lactate) and acceptor (PCE) feed rates, and the addition of
YE greatly improves cell yield.
The initial stages of inoculum preparation are characterized by rapid growth of non- Dhc
organisms in the culture, while the growth of Dhc exhibits a short lag period and then is
relatively constant to final Dhc concentrations of > 10 11 /L. The inoculum preparation protocol
presented here is scalable to 550-L and 3,200-L batches, and produces comparable results with
consortia enriched from three different sites. The cultures produced by this protocol still can
completely dehalogenate PCE to ethene, suggesting that the protocol retains organisms capable
of degrading all of the chlorinated PCE daughter products including VC.
The results summarized in this chapter also demonstrate that Dhc -containing cultures
designed for bioaugmentation can be concentrated by cross-flow filtration to reduce shipping
volumes, and that the concentrated cultures can be stored under refrigeration for > 40 days to
allow for injection schedule flexibility. The use of inexpensive soda kegs provides a simple
method for delivering and injecting the concentrated cultures.
With the increased use of bioaugmentation to treat challenging chlorinated ethene con-
taminated sites, the ability to produce large volumes of high density cultures is becoming
increasingly important. This chapter provides information needed to produce Dhc cultures for
bioaugmentation, including at scales suitable for treating large contaminant plumes. However,
additional culture-specific process optimization may be required for reproducible and reliable
large-scale production of other bioaugmentation cultures.
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