A document discusses the adaptation of a patented biomass-digesting process, denoted sequential batch anaerobic composting (SEBAC), to recycling of wastes aboard a spacecraft. In SEBAC, high-solids-content biomass wastes are converted into methane, carbon dioxide, and compost

Chynoweth, David P.

Haley, Patrick J.

Owens, John M.

Teixeira, Arthur A.

NASA Technical Reports Server

NASA Tech Briefs, April 2009 21
Books & Reports
Parallel Hybrid Vehicle 
Optimal Storage System
A paper reports the results of a Hybrid
Diesel Vehicle Project focused on a par-
allel hybrid configuration suitable for
diesel-powered, medium-sized, commer-
cial vehicles commonly used for parcel
delivery and shuttle buses, as the mis-
sions of these types of vehicles require
frequent stops. During these stops, elec-
tric hybridization can effectively recover
the vehicle’s kinetic energy during the
deceleration, store it onboard, and then
use that energy to assist in the subse-
quent acceleration.
This innovation is particularly useful
with energy storage devices where the
state of charge is readily determined by
an easily measurable attribute. The ul-
tracapacitor and pressurized hydraulic
storage cylinder are good examples of
this type. The state of charge, or energy
level, is proportional to the voltage of
the ultracapacitor and pressure of the
hydraulic cylinder. The method is well
suited to hybrid vehicle applications
where the hybrid power is primarily
used during acceleration and decelera-
tion. This method can be executed with
limited vehicle state information. Pri-
marily, the only feedback required is the
state of charge of the energy storage de-
vice, vehicle speed, and operator throt-
tle request.
The Hybrid Booster Drive (HBD) con-
trol system has the potential to have sim-
ilar benefits with modern diesel and
non-diesel engines, and when applied to
optimized drive trains. It has the poten-
tial to deliver equal or better perform-
ance than other systems, and may be
produced at reduced cost and complex-
ity. Test data are available that show the
implementation of the invention during
operation of two prototype hybrid elec-
tric vehicles. 
This work was done by Aaron P. Bloomfield
of Bowling Green State University, Electric Ve-
hicle Institute, for Glenn Research Center.
Further information is contained in a TSP
(see page 1).
Inquiries concerning rights for the commer-
cial use of this invention should be addressed
to NASA Glenn Research Center, Innovative
Partnerships Office, Attn: Steve Fedor, Mail
Stop 4–8, 21000 Brookpark Road, Cleve-
land, Ohio 44135. Refer to LEW-18289-1.
Anaerobic Digestion in a
Flooded Densified Leachbed
A document discusses the adaptation of
a patented biomass-digesting process, de-
noted sequential batch anaerobic com-
posting (SEBAC), to recycling of wastes
aboard a spacecraft. In SEBAC, high-
solids-content biomass wastes are con-
verted into methane, carbon dioxide, and
compost. 
SEBAC includes three stages: For
stage 1, biomass is placed in a vessel,
wherein it is fermented and serves as a
leachbed. Stage 1 is started by recycling,
from stage 3, of leachate, which wets the
bed and inoculates it with microorgan-
isms. After stage 1 has been started, it be-
comes Stage 2, during which leachate is
recycled to keep the bed moist. Stage 2
becomes stage 3 when its leachate is
used to start a new stage 1. Leachate is
conveyed through the leachbeds by grav-
ity and is conveyed between stages by
pumping or gravity, and the beds are not
flooded. The spacecraft version of
SEBAC incorporates modifications to re-
duce the sizes of reactors and enable op-
eration in microgravity. The modifica-
tions include flooding of the leachbeds,
pumping to eliminate reliance on grav-
ity, the use of external liquid/gas separa-
tors, and densification of biomass in the
leachbeds.
This work was done by David P.
Chynoweth, Arthur A. Teixeira, John M.
Owens, and Patrick J. Haley of the University
of Florida for Johnson Space Center. For fur-
ther information, contact the JSC Innovation
Partnerships Office at (281) 483-3809. 
In accordance with Public Law 96-517,
the contractor has elected to retain title to this
invention. Inquiries concerning rights for its
commercial use should be addressed to:
University of Florida 
Environmental Systems 
Commercial Space Technology Center
AP Black Hall
P.O. Box 116450
Gainesville FL 32611-6450
Phone No.: (352) 392-7814
Fax No.: (352) 392-3673
Refer to MSC-23815-1, volume and num-
ber of this NASA Tech Briefs issue, and the
page number.
https://ntrs.nasa.gov/search.jsp?R=20090016106 2019-08-30T06:48:33+00:00Z


Anaerobic Digestion in a Flooded Densified Leachbed

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