Determination of Kjeldahl nitrogen in sewage effluents, trade effluents and sewage sludges using a copper-titanium catalyst

Abstract

A method for the determination of Kjeldahl nitrogen has been developed that uses a block digester and a low-toxicity copper-titanium catalyst. A nicotinic acid solution (200.0 mg l^–1 of N) was determined with a standard deviation of 1.6 mg l^–1 of N and a nitrogen recovery of 95.6%. The limit of detection was 0.85 mg l^–1 of N. The development and testing of the method on sewage effluents, trade effluents and sewage sludges is presented. Results are compared with those obtained by the widely accepted mercury catalyst method.