Hydromantis Toxchem 4.3.5 Hydromantis Toxchem is mainly used for estimating VOC air emissions from wastewater collection, preliminary/primary/secondary treatment and disposal facilities. The site specific wastewater characteristics, contaminant properties and the process design and operating information are used to estimate VOC emission rates. In addition to air emission estimates, Toxchem can also be used to estimate the concentrations/loads of contaminants in the water effluent, or oil and residual solids streams. Toxchem is based on fundamental mass transfer equations and mass balances including the removal mechanism of stripping and volatilization, biodegradation and sorption. Thus, it can also be used to determine the fate of any synthetic chemical compounds for which the physical, chemical and biodegrading properties are known.