Polyhydroxyalkanoate levels as an indicator of bioreactor health
AssigneeE. I. Du Pont de Nemours and Company
InventorsDominic A. Dragotta, Vasantha Nagarajan, Stuart M. Thomas
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Abstract
A method has been developed to monitor the health of an activated sludge environment in a wastewater process comprising monitoring the levels of polyhydroxyalkanoates (PHA) produced and correlating those levels with various selected sample parameters. In general, levels of PHA in excess of about 15% to about 20% dry weight of the biomass is an indication that the biocatalytic efficiency of the wastewater treatment process is impaired.
Claims16
A method for monitoring and controlling the biocatalytic efficiency of a wastewater treatment process comprising:
- a) providing an activated sludge environment comprising:
- (i) a carbon influx;
- (ii) cultures of autotrophic, heterotrophic and facultative microorganisms;
- (iii) a feed nutrient;
- and
- (iv) an end electron acceptor
- b) sampling wastewater from anaerobic, anoxic and/or aerobic stages of the treatment process;
- c) measuring the concentration of an internal storage molecule present in the sample to determine the status of a selected sample characteristic;
- and
- d) adjusting the feed nutrient in the activated sludge environment depending on the status of the selected sample wherein the biocatalytic efficiency of a wastewater treatment process is controlled.
A method of maintaining a viable culture in an activated sludge environment in the absence of carbon influx comprising:
- a) providing an activated sludge environment comprising:
- (i) a carbon influx;
- (ii) cultures of autotrophic, heterotrophic and facultative microorganisms;
- (iii) a feed nutrient;
- and
- (iv) an end electron acceptor;
- b) removing the feed nutrient from the activated sludge environment while continuously monitoring the concentration of polyhydroxyalkanoates present in the activated sludge environment;
- c) removing the carbon influx from the activated sludge environment when the concentration of polyhydroxyalkanoates is greater than about 15 to about 20 dry weight percent of the biomass;
- d) adding a minimal concentration of nitrate to the activated sludge environment of step (c);
- wherein the cultures of autotrophic, heterotrophic and facultative microorganisms are maintained in a viable state in the absence of a carbon influx.
Dependencies are inferred from the claim text.