5. ODOR EMISSIONS
To date, a problem that limits the implementation of these new sludge drying technologies is related to odor emissions. These systems, in fact, could cause significant odor emissions related to the handling, treatment and storage of sludge which would add up to those normally present in the plant.
The treatment and abatement of odor emissions cannot ignore the knowledge of the processes and specific processing stages from which these emissions are generated. The knowledge of these elements allows to identify the most appropriate ways of controlling, inhibiting and / or mitigating the emission and which consist of:
1. Palliative methods (for example the use of substances with a pleasant smell or coverings of the sources);
2. Preventive methods (preventive reduction of emissions at source by eliminating foul-smelling substances or limiting the conditions that favor their formation and release into the atmosphere);
3. Curative methods (capture and subsequent treatment for purification of emissions).
The first two methods require some planning and management measures which may, at times, be either economically too expensive or not sufficient for the solution of the problem.
The third method, on the other hand, involves the use of appropriate treatment technologies which, by removing the pollutant from the captured air, operate when the emission has already formed. The main technologies for the treatment of odor emissions known to date can be classified in consideration of the principle of action: physical (adsorption), chemical (absorption, thermal oxidation, catalytic oxidation, nebulization, ionization, photo-oxidation and incineration) and biological ( scrubber, biotrickling, biofiltration).
It is therefore of fundamental importance to install a system for the control of odor emissions by means of a perimeter detection probe and to equip the system with a diffusion model that, using software, allows the representation on a map of the actual diffusion “plume”.
The TOM (Total Odor Management) software is a suite for managing and monitoring the odor emissions of a plant. It receives the meteoclimatic data from the control unit and from the analyzers installed on the system and calculates the olfactory impact represented by the odor dispersion plume expressed in olfactory-metric units per cubic meter, using the mathematical model of odor fallout called “AERMOD ”, Typically updated every 5 minutes.
The TOM program resides on the cloud and does not require a dedicated computer; all the calculations are available in real time by accessing the dedicated website with your credentials. The representation of the odor plume, viewable on PC, tablet and smartphone; depict the current olfactory impact or any previous situation.
The olfactory impact is calculated in reverse modeling mode: the software calculates the odor flow value of the sources based on the odor concentration detected by the analyzer positioned downwind, after which it assigns the odor flow value calculated to the sources and calculates it the plume of odor emitted.