Microbiological fixed-bed process was developed in which supplementary oxygen required by microbial species is supplied by electrochemical device. Rate of addition of oxygen to waste treatment process is controlled to maintain aerobic metabolism and prevent anaerobic metabolisms which produce odorous or toxic products

Hooper, T. J.

Silverman, H. P.

Weliky, N.

English

NASA Technical Reports Server

September 1972
	 B72-10557 
NASA TECH BRIEF 
Ames Research Center
	 -4r 
NASA Tech Briefs announce now technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
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be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Metered Oxygen Supply Aids Treatment

of Domestic Sewage 
Microbiological waste-treatment processes are 
widely used for converting domestic wastes into sub-
stances such as carbon dioxide, nitrates, phosphates, 
amino acids, etc. However, disposal of sewage which 
is heavily loaded with solids is difficult because more 
oxygen is required than can be supplied by the 
amount that is normally present in the sewage, and 
ordinary waste treatment facilities seldom are de-
signed to cope with heavily loaded sewage. 
A microbiological fixed-bed process has been de-
veloped in which the supplementary oxygen required 
by microbial species is supplied by an electrochemical 
device; the rate of addition of oxygen is controlled to 
maintain aerobic metabolism and prevent anaerobic 
metabolisms which produce odorous or toxic products. 
The experimental electrochemical device is shown 
schematically in the diagram; it consists of a hollow 
cell or chamber (separated into two parts by a mem-
brane permeable to salts), two electrodes, and two 
elastomeric gaskets. The two electrodes can be made 
of platinum or other inert, conducting material and 
are located on opposite sides of the permeable mem-
brane. Holes are located in the anode compartment 
for introduction and removal of the waste mixture, 
and in the cathode compartment for flow of electro-
lyte and removal of hydrogen. 
In experiments with this model, the cell was tilted 
at an angle of 15° with the anode facing up. Waste 
mixture was allowed to drop on the anode until it was 
covered with a bed of microbial growth which also 
filled the gap between the anode and membrane so 
that a conductive bridge was present between the
anode and cathode electrolytes. Sewage could be 
dripped over the microbial bed at such a rate that 
dissolved oxygen in the effluent was maintained con-
stant at selected concentrations. Under these condi- 
Reference 
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tions, oxygen was supplied at the rate at which it was 
consumed; an excess was maintained to avoid anaero-
bic conditions in the system. 
By measurement of oxygen concentration and ad-
justment of the rate of generation of oxygen (so that 
the concentration remains constant with time), sewage 
utilization rates may be determined, or constant con-
centrations of reactants or products may be main-
tained, depending on requirements. 
The form, shape, and size of the devices may be 
modified. Cells may be combined in series or parallel 
to accommodate the requirements placed on their use. 
Notes: 
1. The following documentation may be obtained 
from:
(continued overleaf) 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that Such use Government nor any person acting on behalf of the United States
	 will be free from privately owned rights. 
https://ntrs.nasa.gov/search.jsp?R=19720000556 2020-03-17T03:34:35+00:00Z
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $6.00 
(or microfiche $0.95) 
Reference: 
NASA CR-73033 (N66-39889), Applications 
of Immobilized Biological Agents to Waste 
Treatment. 
No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: B72-10557
Patent status: 
NASA has decided not to apply for a patent. 
Source: Norman Weliky, Thomas J
.
 Hooper, and
Herbert P. Silverman of
TRW, Inc. Systems Group 
under contract to
Ames Research Center
(ARC-10024) 
B72-10557	 Category 05


Metered oxygen supply aids treatment of domestic sewage

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