Experimental validation of a single-OUR method for wastewater RBCOD characterisation

Wastewater characterisation is of primary importance for the correct design and management of a treatment plant. The aim of this work was the evaluati on of a new rapid and easy to use respirometric. technique for the characte risation of readily biodegradable COD (RBCOD). When the necessary calibrati on curve is obtained, the RBCOD assessment procedure needs less than 30 min utes. On the contrary, conventional techniques require some hours. The firs t step consists in calculating a calibration curve in order to point out th e correlation between oxygen consumed and known amount of added Sodium Acet ate. To a well aerated biomass (in order to remove residual readily biodegr adable substrate) a known amount of Sodium Acetate is added and the related OUR is measured. The oxygen consumed (Delta DO) is related to the added CO D (as Sodium Acetate). Therefore, the RBCOD concentration in wastewater sam ples can be obtained according to the following steps: (1) measure Delta DO ; (2) multiply Delta DO by the Volume of aerated mixed liquor used in the t est; (3) from the calibration curve, calculate the readily biodegradable CO D equivalent to Acetate; (4) estimate RBCOD concentration multiplying the w astewater sample volume tested in the reactor. Some advantages of this tech nique are described in the paper.