Table 4.

Examples of recent applications of analytical techniques for the waste treatment processes monitoring.

Application	Methodology	Main Outcome of the Work	Ref.
Monitoring of VOCs released during initial stages of waste treatment	GC-MS, calculation of OAV	The EBW proportion in waste is the dominate source of VOCs	[7]
Monitoring of VOCs released during composting of food, yard and paper wastes	GC-MS	Waste origin plays a crucial role on the chemical composition of VOCs	[72]
Monitoring of VOCs released during household composting of food wastes	GC-MS, physicochemical measurements, PCA	PCA applied to VOCs and physicochemical parameters is a sufficient tool for the monitoring of the composting process	[73]
Biofiltration efficiency assessment	Ammonia electrochemical sensor	Waste origin plays a crucial role on the biofiltration efficiency	[74]
Monitoring emissions of odorants released from waste biogas plants	Multi-gas detector (PID and H2S, NH3, CH3SH electrochemical sensors), calculation of OAV	Odorant concentrations and odor activity value can be useful tools for the control of technological processes	[75]
Monitoring of biogas generated from landfills	Internet of Things system equipped with gas sensors	Biogas content emitted from landfills may present dangers and sanitary risks	[76]