The issue of toxic substances occurring in wastewater or sewerage (H2S, CH4, CO2, CO, VOC, various micropolutants such as pesticides, pharmaceuticals, drugs and others) comes to the fore not only for technologists and environmental chemists. In addition to the toxicity and potential risk of explosion that these substances exhibit,

they are able to accelerate corrosive happening in the sewerage network. Also, certain types of micropolutants or pathogens represent a significant risk factor for the purification process, in which, in particular, they are not completely removed or cumuliated and enter surface, sublimation or soil sludge.

An essential part of the solution to this problem is, on the one hand, the rapid detection and monitoring of these substances, on the basis of which procedures suitable for their necessary elimination can also be selected.

Therefore, in the present project, we focus on the development of intelligent sensory technologies that will be able o record the online presence of selected substances and the data obtained will also be accessible for operation through an online application network to ensure their safety at work. The devices will be able to monitor several sewerage monitoring points simultaneously, which can create an interactive map and thus capture illegal discharges of wastewater, or capture the increased incidence of specific micropolutants. The results obtained from the monitoring can then be used for the design of technologies in combination with SMART sensors, for the rapidremoval of selected toxic substances, with particular attention to the use of iron cations (Fe2+, Fe3+ and Fe6+).

The effect of Fe2+ and Fe3+ cations on the precipitation of sulphur compounds and the coagulation of organicsubstances is quite high, but it is necessary to optimise their dosing in real time in the sewer system, which will bedirectly dependent on online detection, but also on the properties and composition of wastewater.