EFFECTS OF C$sup 14$ AND Sr$sup 90$ ON ANAEROBIC DIGESTION

Investigations on the effects of C/sup 14/ and Sr/sup 90/ and their distribution during anaerobic digestion are reported. The rate of gas production from similarly prepared, seeded mixtures with and without C/sup 14/ was not significantly affected up to 1000 mu C/l. Ultimate production of gas, lag-phase period, volatile acids concentration, and reduction of volatile matter were not deleteriously affected by concentration of C/sup 14/ up to 1000 mu C/l. Although statistically significant lower CO/sub 2/ concentrations were found in most of the digesters containing stable or radioactive acetate, the average concentrations differed by no more than 1 to 3%. In the Sr/sup 90/studies, it was concluded that no deleterious effects were observed on gas production in the presence of Sr/sup 90/ concentrations from 10 to 500 mu C/l. Ultimate gas production values, lag-phase periods, volatile acids concentrations, and reduction of volatile matter were not significantly affected by concentrations of Sr/sup 90/ up to 500 mu C/l. Sr/sup 90/ in concentrations from 10 to 500 mu C/ l exerted no significant effect on sludge gas quality as determined by daily gas chromatographic analyses. From a study of decontamination factors (A/sub o//A/ sub t/) to establish the distribution of Sr/sup 90/more » in sludge, it was found that the concentration of radioactivity in the sludge solids is greater at the end of the digestion period than at the beginning. (Public Health Eng. Abstr., 43: No. 8)« less