Accurate nitrogen and organic carbon measurement in sewage

Total organic carbon (TOC) measurement and total nitrogen bonded  (TNb) measurement has key importance to correct exploitation of sewage treatment stations. During the process of denitrification, ammonic nitrogen is first converted into nitrates and nitrites, then into unbonded nitrogen (N2). The conversion happens in an environment devoid of oxygen, through microorganisms with access to organic carbon to supply their metabolic processes.

The optimal ratio of carbon to nitrogen for these processes equals about 10:1. In typical communal sewage, it is instead equal to around 5:1, and the addition of industrial wastes and fluctuation of other process parameters can additionally affect it. Various methods are utilized to restore the optimal carbon to nitrogen proportion, as a last resort they can be restored through dosage of carbon compounds. For optimal control of this process, it’s key to measure the values of both carbon and nitrogen. The Tocadero One digital analyzer from Horiba Tocadero is the perfect device for such measurements.

The device allows for an effective measurement of organic carbon in the range of 0-1000mg/l and nitrogen in the range of 0-200mg/l. The device operates by subjecting samples to mineralization in a 1200°C furnace, as well as an electrochemical nitrogen sensor. The analysis is conducted from a 0,2ml sample each 5-10 minutes. The device only requires maintenance once every 6 months, and the cost of exploitation materials does not exceed 1000EUR. The state of elements that wear down over time is monitored by the device’s predictive functionalities.