2006 Volume 35 Issue 3 Pages 208-215
A sensitive and simplified analytical method for the concentration of insoluble nitrogen in activated sludge has been developed. Nitrogen concentration in activated sludge was measured by ultra-violet absorption spectrochemical analysis. The sensitivity of the nitrogen concentration was improved by H2O2 addition or O3 injection. The H2O2 and O3 content in 1mg activated sludge were 0.125ml to 1.0ml (30% H2O2), and 1.0ml (O3), respectively. So far, the sensitivity difference between these methods and Kjeldal's method, which is the established quantitative method, was within 5%. The live slopes between these methods and Kjeldahl's method were about 1, and the correlation coefficients were 0.992 (H2O2 addition) and 0.964 (O3 injection) . These methods were 33% faster than Kjeldahl' s method. These results indicate that the proposed simplified method using UV absorption spectrochemical analysis can be applied to nitrogen concentration measurements in activated sludge with high sensitivity.
