In the cases in which the Life Cycle Inventory (LCI) data available in the literature only include pretreatment information, there is a need to use a model for waste treatment to estimate the post-treatment data. In other cases, it is desirable to back calculate pretreatment information from final environmental emissions. This paper presents treatment modules for Wastewater Treatment Plant (WWTP), Solvent Incinerator, and Solvent Recovery. The modules were developed based on design equations and average Literature data. The methodology and basis for the models are presented and results are shown for the three modules. The modules developed present an easy and scientifically-based method to obtain post-treatment LCI data. The modules are expected to be particularly useful in the instances when process design techniques are employed for the estimation of LCI data, especially in chemical, biochemical and pharmaceutical industries.